UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Effect of gamma irradiation on turkey meat protein and its emulsifying capacity. Lin, Ting-shen 1970

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1970_A6_7 L55_2.pdf [ 4.49MB ]
Metadata
JSON: 831-1.0093360.json
JSON-LD: 831-1.0093360-ld.json
RDF/XML (Pretty): 831-1.0093360-rdf.xml
RDF/JSON: 831-1.0093360-rdf.json
Turtle: 831-1.0093360-turtle.txt
N-Triples: 831-1.0093360-rdf-ntriples.txt
Original Record: 831-1.0093360-source.json
Full Text
831-1.0093360-fulltext.txt
Citation
831-1.0093360.ris

Full Text

EFFECT OF GAMMA IRRADIATION ON TURKEY MEAT PROTEIN AND ITS EMULSIFYING CAPACITY by TING-SHEN LIN S., Taiwan P r o v i n c i a l Chung-Hsing University, A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of Food Science We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA September, 1970 In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study . I f u r t h e r agree t h a t permiss ion fo r e x t e n s i v e copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r e p r e s e n t a t i v e s . I t i s understood that copying o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l ga in s h a l l not be a l lowed without my w r i t t e n p e r m i s s i o n . Department of The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada ABSTRACT The effect of gamma i r r a d i a t i o n on the emulsifying capacity of turkey l i g h t meat was studied i n a model system. A change of emulsifying capacity due to the changes of functional c a p a b i l i t i e s of sa l t - s o l u b l e proteins were studied on the i r r a d i a t e d s a l t - s o l u b l e - p r o t e i n extract by disc electrophoresis, viscometry, fluorescence spectroscopy and measurement of pH. The formed emulsions were taken f o r examination of the p a r t i c l e size under the microscope, measurement of the v i s c o s i t y with a Haake Rotovisco Viscometer, and f o r the determination of the s t a b i l i t y by a method of centrifugation and cooking. I r r a d i a t i o n of turkey meat at doses of 1 or 3 Mrad increased the emulsifying capacity of the tissue but doses of 2 or ^ Mrad decreased capacity r e l a t i v e to an unirradiated control. I r r a d i a t i o n had no effect on the e x t r a c t a b i l i t y of salt-soluble proteins. The emulsifying capacity of i r r a d i a t e d salt-soluble-protein extract increased s i g n i f i c a n t l y ( p < : 0 . 0 5 ) and v i s c o s i t y decreased s i g n i f i c a n t l y ( p < 0 . 0 5 ) with increasing dose of i r r a d i a t i o n from 0 to 2 Mrad. Doses of 3 or ^ Mrad f a i l e d to produce further s i g n i f i c a n t change i n either variable. I r r a d i a t i o n of the salt-soluble-protein extract also resulted i n a decrease i n p a r t i c l e size of the emulsion; an increase i n v i s c o s i t y of the emulsion; an increase of hydrophobic effect i n the sal t - s o l u b l e - p r o t e i n molecule; an increase i n the electrophoretic mobility of the two main protein fractions on polyacrylamide g e l ; an increase i n pH; and an increase i n the s t a b i l i t y of emulsions judged on the basis of volume of o i l i n the supernatant a f t e r c e n t r i -fugation and cooking. i i i TABLE OP CONTENTS Page INTRODUCTION 1 LITERATURE REVIEW 3 Meat E m u l s i o n 3 S t a b i l i t y of E m u l s i o n 8 E f f e c t o f I r r a d i a t i o n on F r e s h Meat 9 E f f e c t o f I r r a d i a t i o n on Amino A c i d s and P r o t e i n s 11 EXPERIMENTAL METHODS 16 Source and Treatment of Samples ' 16 S a l t - S o l u b l e P r o t e i n s 16 I r r a d i a t i o n , 18 Measurement o f t h e V i s c o s i t y o f S a l t - S o l u b l e P r o t e i n s 19 pH Measurement 20 D i s c E l e c t r o p h o r e s i s , 20 F l u o r e s c e n t Study o f t h e Hy d r o p h o b i c E f f e c t of S-S-P 21 E m u l s i f y i n g C a p a c i t y 22 S l i d e P r e p a r a t i o n 23 Measurement o f t h e V i s c o s i t y of E m u l s i o n 2^ S t a b i l i t y of E m u l s i o n 25 RESULTS AND DISCUSSION 26 E x t r a c t a b l l i t y 26 V i s c o s i t y of S a l t - S o l u b l e - P r o t e i n E x t r a c t 27 pH . • 31 TABLE OF CONTENTS - C o n t i n u e d Page D i s c E l e c t r o p h o r e t i c A n a l y s i s 32 F l u o r e s c e n t Study o f t h e H y d r o p h o b i c E f f e c t of S-S-P 38 E m u l s i f y i n g C a p a c i t y 4o M i c r o s c o p i c E x a m i n a t i o n of t h e E m u l s i o n — • 44 V i s c o s i t y of E m u l s i o n 46 S t a b i l i t y o f ' E m u l s i o n • 49 SUMMARY 50 BIBLIOGRAPHY 52 V LIST OF FIGURES F i g u r e Page 1 Flow diagram of e x p e r i m e n t a l p r o c e d u r e 17 2 Arrangement of a p p a r a t u s f o r d e t e r m i n a t i o n of e m u l s i f y i n g c a p a c i t y 22 3 E l e c t r o p h o r e t i c p a t t e r n o f t h e s a l t - s o l u b l e p r o t e i n s i r r a d i a t e d a t 0 Mrad ( C o n t r o l ) 33 4 E l e c t r o p h o r e t i c p a t t e r n of t h e s a l t - s o l u b l e p r o t e i n s i r r a d i a t e d a t 1 Mrad 3^ 5 E l e c t r o p h o r e t i c p a t t e r n o f t h e s a l t - s o l u b l e p r o t e i n s i r r a d i a t e d a t 2 Mrad 35 6 E l e c t r o p h o r e t i c p a t t e r n o f t h e s a l t - s o l u b l e p r o t e i n s i r r a d i a t e d a t 3 Mrad r 36 7 E l e c t r o p h o r e t i c p a t t e r n o f t h e s a l t - s o l u b l e p r o t e i n s i r r a d i a t e d a t 4 Mrad 37 8 P h o t o m i c r o g r a p h s o f e m u l s i o n s formed from 30 ml of c o n t r o l o r i r r a d i a t e d s-s-p e x t r a c t s mixed w i t h 65 ml o f o i l 45 9 Apparent v i s c o s i t y - s h e a r r a t e r e l a t i o n s f o r e mulsions 48 \ v i LIST OF TABLES T a b l e Page 1 E f f e c t o f i r r a d i a t i o n o f t u r k e y l i g h t meat on t h e e x t r a c t a b l l i t y o f meat p r o t e i n 2 6 2 E f f e c t of i r r a d i a t i o n o f s a l t - s o l u b l e -p r o t e i n e x t r a c t (7«8 mg/ml) on v i s c o s i t y 28 3 A n a l y s i s of v a r i a n c e f o r d a t a of T a b l e 2 showing t h e i s o l a t i o n o f t h e l i n e a r , q u a d r a t i c , c u b i c and q u a r t ! c components of t h e t r e a t m e n t sum of square 28 ^ E f f e c t o f i r r a d i a t i o n of t u r k e y l i g h t meat and o f s a l t - s o l u b l e - p r o t e i n e x t r a c t (7.8 mg/ml) on pH 31 5 E f f e c t o f i r r a d i a t i o n of s a l t - s o l u b l e p r o t e i n on t h e b i n d i n g of ANS 39 6 E f f e c t o f i r r a d i a t i o n on t h e e m u l s i f y i n g c a p a c i t y o f t u r k e y l i g h t meat k-1 7 E f f e c t o f i r r a d i a t i o n o f s a l t - s o l u b l e -p r o t e i n e x t r a c t (7.8 mg/ml) on e m u l s i f y i n g c a p a c i t y 8 P J i e o l o g i c a l parameters f o r emul s i o n s formed from c o n t r o l and i r r a d i a t e d s-s-p e x t r a c t s and r e s u l t s o f t h e s t a t i s t i c a l a n a l y s i s o f t h e l e a s t -s q uares f i t o f t h e d a t a t o t h e Power Law e q u a t i o n h~ 9 E f f e c t o f i r r a d i a t i o n o f s a l t - s o l u b l e -p r o t e i n e x t r a c t on t h e s t a b i l i t y o f for c i e d e m u l s i o n s ^9 v i i ACKNOWLEDGEMENT The writer wishes to express his appreciation for assistance i n t h i s study by : Dr. J.F. Richards, who directed t h i s research, provided encouragement and advice, Professor E.L. Watson, for counsel on the aspects of viscometry of samples, Dr. S. Nakai, f o r counsel on the aspects of fluorescent study, Dr. M.A. Tung, fo r suggestion and assistance i n the use of the I.B.M. 3^0 computer and provision of computer programmes, Dr. W.D. Powrie and Dr. P.M. Townsley, f o r serving on the research committee and reviewing t h i s paper, Mrs. B.C. Morrison, f o r assistance i n setting up the beginning experimental work, Mr. R. Whiting, f o r assistance i n the microscopic photography, The Atomic Energy Committee, f o r providing the Gamma-Cell. INTRODUCTION The a r t o f making sausage ( r e f e r r e d t o as a meat e m u l s i o n ), a l t h o u g h known and p r a c t i c e d f o r c e n t u r i e s t h r o u g h o u t t h e w o r l d , s t i l l remains one of t h e youngest major a r e a s i n f o o d s c i e n c e . Most of t h e r e s e a r c h d a t a on meat emul s i o n s has been p u b l i s h e d subsequent t o t h e f i r s t model system d e v e l o p e d by S w i f t et a l i n I 9 6 I . Sausage may be d e f i n e d as a f o o d p r e p a r e d from chopped and seasoned meat and formed i n t o an e m u l s i o n t y p e i n which, t h e muscle p r o t e i n a c t s as t h e p r i m a r y e m u l s i f y i n g a g e n t . The formed e m u l s i o n has c h a r a c t e r i s t i c s s i m i l a r t o an o i l - i n - w a t e r e m u l s i o n . Osipow (1962) s t a t e d t h a t t h e p a r t i c l e s i z e i n an e m u l s i o n may v a r y from 0.1 m i c r o n t o 50 m i c r o n s . However, a c t u a l commercial meat emulsions p o s s e s s a f a t p a r t i c l e s i z e much l a r g e r t h a n 50 m i c r o n s . Thus, on t h e b a s i s o f p a r t i c l e s i z e meat e m u l s i o n s can not be c o n s i d e r e d t o be t r u e e m u l s i o n s . However, meat e m u l s i o n systems r e a c t l a r g e l y a c c o r d i n g t o e m u l s i o n t h e o r y ( S a f f l e , 1968 ). F a c t o r s such as pH, t y p e s o f p r o t e i n and f a t , s h e ar f o r c e , t e m p e r a t u r e , s a l t , f i l l e r s o r b i n d e r s , f a t p a r t i c l e s i z e , p r e r i g o r , f r e s h and f r o z e n meat, i o n s , m i c r o o r g a n i s m s , e t c . , which a f f e c t t h e f o r m a t i o n o f a meat e m u l s i o n have been s t u d i e d by s e v e r a l w o r k e r s . I n t h e f i e l d of i r r a d i a t i o n , t h e e f f e c t of i r r a d i a t i n g commercial 2 emulsion products on extending storage l i f e has been reported by Coleby et a l (1962). It has also been reported that gamma i r r a d i a t i o n of raw meat may produce severe adverse changes i n meat qu a l i t y ( Hannan et a l , 1 9 5 9 ; Coleby et a l , I 9 6 I ). However, no research has been done on the effect of i r r a d i a t i o n on the value of ti s s u e used f o r meat emulsions. Although the pet i t i o n s of food regulatory agencies for clearance of i r r a d i a t e d foods including poultry meat fo r human consumption have not yet been approved because of the p o s s i b i l i t y of induced t o x i c i t y , many believe that t h i s hazard i s very low and that approval w i l l eventually be granted ( Goldblith, 1970 ; Tape, I 9 6 8 ) . The objective of t h i s i n v e s t i g a t i o n was to evaluate i n a model system the value of i r r a d i a t e d poultry meat for use i n meat emulsion products and to study the effect of i r r a d i a t i o n on the changes of functional c a p a b i l i -t i e s of meat proteins, e s p e c i a l l y the sa l t - s o l u b l e proteins, as r e f l e c t e d by t h e i r emulsifying capacity. LITERATURE REVIEW Heat Emulsion A meat emulsion may be defined as a two-phase system, consisting of a f a i r l y coarse dispersion of s o l i d (fat) i n a l i q u i d (water) (Sa f f l e , 1968). Osipow (1962) stated that the p a r t i c l e size i n a true emulsion may vary from 0.1 micron to 50 microns. From photomicro-graphs ( Hansen, i960 ; Helmer and S a f f l e , 1963 ) of actual commercial meat emulsions, the fat p a r t i c l e s wer found to be larger than 50 microns ; thus on the basis of p a r t i c l e size alone, the meat emulsions can not be considered to be true emulsion, ( S a f f l e , I968 ). In an emulsion, the emulsifying agent i s required to act as a s t a b i l i z e r at the interface between the disperse (fat) and continuous (water) phases to reduce the i n t e r f a c i a l tension. The main c h a r a c t e r i s t i c of an emulsifying agent i s that i t has a f f i n i t y f o r both water and fat when i t i s absorbed at the interface. This dual a f f i n i t y i s s a t i s f i e d when the hydrophilic portion i s oriented toward the water and the l y o p h i l i c part toward the f a t . The emulsifying agents i n meat emulsions are the soluble proteins,.especially those which are s a l t - s o l u b l e . The term, sal t - s o l u b l e proteins ( s-s-p ), i s commonly used to mean those proteins which are sal t - s o l u b l e and 4 i n c l u d e s some which a r e a l s o w ater s o l u b l e ( S a f f l e , I 9 6 8 ) . Both s a l t - and w a t e r - s o l u b l e p r o t e i n s can a c t as an e m u l s i f y i n g a g e n t s i n such a manner t h a t t h e n o n - p o l a r groups a r e a t t r a c t e d t o t h e o i l phase, w h i l e t h e p o l a r groups a r e a t t r a c t e d t o t h e w ater phase. These r e a c t i v e groups may be a v a i l a b l e f o r i n t e r a c t i o n , but on t h e o t h e r hand, t h e y may be b u r i e d i n t h e s t r u c t u r e of t h e p r o t e i n . S w i f t et a l (1961) r e p o r t e d t h a t Qk.$% of t h e s-s-p and 66,6% o f t h e x ^ a t e r - s o l u b l e p r o t e i n s were removed from s o l u t i o n d u r i n g e m u l s i f i c a t i o n . T h i s i n d i c a t e s t h a t t h e s-s-p were u t i l i z e d more c o m p l e t e l y t h a n t h e w a t e r - s o l u b l e p r o t e i n s . S w i f t (I965) proposed t h a t t h e e m u l s i f y i n g c a p a c i t y of t h e s-s-p was 30 - ^00% more e f f e c t i v e t h a n t h a t of t h e w a t e r - s o l u b l e p r o t e i n s . H e g a r t y et a l (1963) r e p o r t e d t h a t myosin p o s s e s s e d t h e g r e a t e s t e m u l s i f y i n g c a p a c i t y among t h e s-s-p. C a r p e n t e r and S a f f l e (1965) e x p l a i n e d t h a t t h e g r e a t e r e m u l s i f y i n g c a p a c i t y of t h e s-s-p i s p r o b a b l y due t o d i f f e r e n c e s i n t h e shape of t h e m o l e c u l e s . E l o n g a t e d m o l e c u l a r p r o t e i n shapes such as t h a t o f t h e myosin m o l e c u l e a r e thought t o r e s u l t i n a g r e a t e r i n c r e a s e i n t h e v i s c o s i t y of t h e c o n t i n u o u s phase and t o s p r e a d as a f i l m o v e r a g r e a t e r f a t s u r f a c e a r e a t h a n more s p h e r i c a l shapes. The c o n f i g u r a t i o n o f t h e myosin m o l e c u l e i n d i c a t e s l o n g s t r a i g h t s t r e t c h e s o f h i g h h e l i c a l c o n t e n t , which e x t e n d f o r a l m o s t 1300 angstrom i n t h e " t a i l " r e g i o n ( Lowey et a l , 1962, 1966 ; R i c e et a l , 1966 ). The t r o p o m y o s i n m o l e c u l e i s of s i m i l a r 5 c o n s t r u c t i o n but s h o r t e r ( Kominz et a l , 195^ ; Lowey et a l , 1966 ). The fo r m a t i o n of such s t r u c t u r e s i s made p o s s i b l e by the i n t e r a c t i o n s of the l a r g e numbers of n e g a t i v e l y and p o s i t i v e l y charged s i d e - c h a i n s a l o n g the molecules ( B e n d a l l , 1969 )• Knowledge on meat emulsions has been obtained with the use of commercial p r o d u c t i o n - t y p e equipment. However, such equipment has many major disadvantages f o r st u d y i n g many of the fundamental f a c t o r s i n meat emulsions. For example, i t i s v e r y d i f f i c u l t and sometimes i m p o s s i b l e t o m a i n t a i n c o n t r o l of f a c t o r s s u f f i c i e n t t o permit a c c u r a t e estimates of treatment e f f e c t s . A model system-was t h e r e f o r e developed t o study the e f f e c t of v a r i o u s f a c t o r s on e m u l s i f i c a t i o n i n meat p r o t e i n system ( S w i f t et a l , I96I ; Carpenter and S a f f l e , 196^ ). S e v e r a l f a c t o r s have been i d e n t i f i e d as important determinants of e m u l s i f y i n g c a p a c i t y i n such model system. For example s 1. pH ; 2. the c o n c e n t r a t i o n of p r o t e i n ; 3» temperature ; ^. r a t e of a d d i t i o n of f a t ; and 5' speed of mixing d u r i n g e m u l s i f i c a t i o n . 1. pH a f f e c t s e m u l s i f i c a t i o n through i t s marked i n f l u e n c e on the p r o p e r t i e s of p r o t e i n s . Carpenter and S a f f l e (1965) r e p o r t e d t h a t as the pH i n c r e a s e s from 6.0 t o 9«0 t h e r e was a corresponding i n c r e a s e i n the v i s c o s i t y of s-s-p i n d i c a t i n g a change i n both the shape and the net charge of p r o t e i n s molecules. The c o r r e l a t i o n c o e f f i c i e n t ( r ) between t h e l i m i t i n g v i s c o s i t y number ( i n t r i n s i c v i s c o s i t y ) and t h e e m u l s i f y i n g c a p a c i t y was + O.97. C o n f l i c t i n g r e s u l t s were r e p o r t e d by S w i f t and S u l z b a c h e r ( I 9 6 3 ) w h o found e m u l s i f y i n g c a p a c i t y o f t h e s-s-p was maximum a t pH 6.0 - 6.5 and d i d not change when t h e pH was i n c r e a s e d t o 8.0. 2. I t has been e s t a b l i s h e d t h a t i n model systems l e s s f a t i s e m u l s i f i e d p e r u n i t of p r o t e i n as t h e p r o t e i n c o n c e n t r a t i o n i s i n c r e a s e d ( H e g a r t y et a l , 19&3 » Trautmen, 1964 ; S w i f t , 1965 ; C a r p e n t e r and S a f f l e , 1964 ). H e g a r t y et a l (1963), Trautman (1964) and S w i f t (I965) o b s e r v e d a c u r v i l i n e a r r e l a t i o n between t h e c o n c e n t r a t i o n o f t h e p r o t e i n and t h e e m u l s i f y i n g c a p a c i t y o f s e v e r a l o f t h e p r o t e i n s o r p r o t e i n e x t r a c t s s t u d i e d . However, a s t r a i g h t -l i n e r e l a t i o n was found by C a r p e n t e r and S a f f l e (1964). S a f f l e (1968) i n d i c a t e d t h a t t h e c u r v i l i n e a r r e l a t i o n between t h e c o n c e n t r a t i o n of p r o t e i n and t h e e m u l s i f y i n g c a p a c i t y o f p r o t e i n s was p r o b a b l y due t o o v e r l o a d i n g of t h e system, t h a t i s , p a r t o f t h e e m u l s i o n remained on t h e s i d e of t h e j a r r e s u l t i n g an i n c o m p l e t e m i x i n g as t h e " break p o i n t " was approached. He c o n c l u d e d t h a t t h e r e l a t i o n between t h e c o n c e n t r a t i o n of s o l u b l e p r o t e i n and t h e emul-s i f y i n g c a p a c i t y f o r t h e model system of C a r p e n t e r and S a f f l e (1964) c o u l d be p l o t t e d as a s t r a i g h t - l i n e u n t i l t h e system was o v e r l o a d e d . 3. The t e m p e r a t u r e of p r e p a r i n g t h e e m u l s i o n d u r i n g sausage making i s e x t r e m e l y i m p o r t a n t . I t has been known f o r many y e a r s I n t h e sausage I n d u s t r y t h a t , i f t h e e m u l s i o n i n t h e chopper exceeds 15 - 22 °C an e m u l s i o n breakdown w i l l o c c u r ( S a f f l e , I968 ). S w i f t et a l (1961) r e p o r t e d t h a t a t t e m p e r a t u r e s i n a range from 18 - h6 °C, t h e amount of o i l e m u l s i f i e d was i n v e r s e l y and l i n e a r l y r e l a t e d t o t h e maximum t e m p e r a t u r e a t t a i n e d d u r i n g e m u l s i f i c a t i o n ( r = 0.995 - 0.003 ; p ,$0,001 ). The l a t t e r a u t h o r s i n d i c a t e d t h a t t h e f a c t o r s p o s s i b l y c o n t r i b u t i n g t o t h e u n r e s o l v e d " t e m p e r a t u r e e f f e c t " i n c l u d e (a) a c h a i n o f events l e a d i n g from i n c r e a s e d t e m p e r a t u r e t o d e c r e a s e d s u r f a c e t e n s i o n o f t h e f a t , i n c r e a s e d d i s p e r s i o n and s u r f a c e a r e a , and, c o n s e q u e n t l y , an i n c r e a s e d need f o r s t a b i l i z i n g membranes ; (b) d e n a t u r a t i o n o f p r o t e i n p r i o r t o f o r m a t i o n o f p r o t e c t i v e membranes ; and (c) a l t e r e d f o r m a t i o n o f membranes. Helmer and S a f f l e (I963) p r e s e n t e d d a t a i n d i c a t i n g t h a t p r o t e i n d e n a t u r a t i o n was not t h e cause o f t h e l o w e r e m u l s i f i c a t i o n o f f a t a t h i g h e r t e m p e r a t u r e s . P a r k s (1967) found t h a t h o l d i n g s-s-p e x t r a c t s a t 38 °C f o r 3 hours had no e f f e c t on t h e amount o f f a t which c o u l d be e m u l s i f i e d , but i f h e l d a t 65 °C f o r even a few m i n u t e s , t h e e m u l s i f y i n g c a p a c i t y of t h e s-s-p became n o n e x i s t e n t . S w i f t e t _ a l (196I) r e p o r t e d t h a t t h e r e was a s t r a i g h t - l i n e r e l a t i o n between t h e amount o f f a t e m u l s i f i e d and t h e r a t e o f a d d i t i o n ( r = + O.995 ). C a r p e n t e r and S a f f l e (196^) found a n o n - s i g n i f i c a n t c o r r e l a t i o n c o e f f i c i e n t o f + 0.209 a n d p o s t u l a t e d t h a t t h e r a t e of a d d i t i o n had an e f f e c t on t h e e m u l s i f y i n g c a p a c i t y o n l y when t h e o i l was 8 added a t r a t e s i n excess of t h e c a p a c i t y o f t h e m i x e r so t h a t an e x c e s s i v e t e m p e r a t u r e r i s e o c c u r e d i n t h e e m u l s i o n . 5. S w i f t et a l (1961, I965) r e p o r t e d t h a t t h e e m u l s i o n c a p a c i t y was i n f l u e n c e d by v a r i a t i o n s i n t h e speed of m i x i n g of w a t e r - o i l phases. The l a t t e r a u t h o r s i n d i c a t e d t h a t i n c r e a s i n g t h e r a t e o f m i x i n g o r s h e a r i n g f o r c e , d e c r e a s e s f a t g l o b u l e s i z e and i n c r e a s e s s u r f a c e a r e a , and th u s a l a r g e r a r e a of p r o t e i n membrane becomes n e c e s s a r y a t i n t e r f a c e s . S w i f t (1965) assumed t h a t s m a l l e r g l o b u l e s w i t h t h e i r a p p r o p r i a t e membrane a r e p h y s i c a l l y s t r o n g e r t h a n l a r g e r g l o b u l e s because o f g r e a t e r s t r u c t u r a l s u pport from t h e membrane per u n i t volume of o i l o r f a t . S w i f t ( 1 9 6 l ) r e p o r t e d t h a t t h e i n c r e a s e i n v i s c o s i t y w i t h i n c r e a s i n g r a t e o f s h e a r was a s s o c i a t e d w i t h t h e d e c r e a s e i n p a r t i c l e s i z e . S t a b i l i t y of E m u l s i o n " S t a b i l i t y " of an e m u l s i o n i s u s u a l l y d e f i n e d as t h e t i m e r e q u i r e d f o r a s t a b l e e m u l s i o n ( a s p e c i f i c amount of f a t o r o i l e m u l s i f i e d by a s p e c i f i c amount of s o l u b l e p r o t e i n ) t o break ( t h e c o n t i n u o u s and d i s c o n t i n u o u s phases t o s e p a r a t e ) ( S a f f l e , I 9 6 8 ) . Bennett et a l ( 1 9 6 8 ) r e p o r t e d t h a t one of t h e most i m p o r t a n t s t a b i l i z i n g c h a r a c t e r i s t i c s o f an e m u l s i o n i s i t s c o n s i s t e n t p a r t i c l e s i z e . S m a l l e r p a r t i c l e s i z e s f a v o r g r e a t e r s t a b i l i t y . The l a t t e r a u t h o r s i n d i c a t e d t h a t t h e s i z e of t h e p a r t i c l e s i n an e m u l s i o n i s a f u n c t i o n o f t h e n a t u r e o f t h e phases, t h e q u a n t i t y and t y p e o f s u r f a c t a n t , and t h e p r o c e s s i n g t e c h n i q u e . I n c r e a s i n g t h e amount o f s u r f a c t a n t i n t h e e m u l s i o n w i l l r e s u l t i n s m a l l e r p a r t i c l e s i z e . Adjustment of t h e h y d r o p h i l i c - l i p o p h i l i c b a l a n c e t o s u i t t h e t y p e o f e m u l s i o n w i l l improve t h e e f f i c i e n c y o f t h e s u r f a c t a n t and d e c r e a s e t h e p a r t i c l e s i z e o f t h e e m u l s i o n . Becher (1965), C l a y t o n (195*0 a n d Lowe (1955) r e p o r t e d t h a t t h e h i g h e r t h e v i s c o s i t y of t h e e m u l s i o n t h e more s t a b l e w i l l be t h e e m u l s i o n . B o r c h a r t et a l (1967) r e p o r t e d t h a t t h e f a t p a r t i c l e s i z e i n a commercial meat e m u l s i o n can v a r y from 0.1 t o s e v e r a l hundred m i c r o n s and t h a t t h e e x i s t e n c e o f t h i s v a r i a t i o n i n f a t p a r t i c l e s i z e may t e n d t o d e c r e a s e t h e s t a b i l i t y of t h e meat e m u l s i o n . E f f e c t o f I r r a d i a t i o n on F r e s h Meat Doty et a l (1958) found t h e i n c r e a s e i n non-p r o t e i n compounds i n ground beef o b s e r v e d a f t e r i r r a d i a t i o n was accompanied by an a p p r e c i a b l e d e c r e a s e i n t h e c o n c e n t r a -t i o n of s o l u b l e p r o t e i n s . Zender et a l (1958) a l s o r e p o r t e d a d e c r e a s e i n t h e g l y c i n e - s o l u b l e p r o t e i n c o n t e n t of beef muscle a f t e r i r r a d i a t i o n . E l -Badawi et a l (196^) found a s i g n i f i c a n t i n c r e a s e i n t h e g l y c i n e - N a O H - s o l u b l e p r o t e i n s c o n t a i n e d i n t h e d r i p f l u i d from i r r a d i a t e d b e e f . On t h e o t h e r hand, A n g l e m i e r et a l (196^) added t h e d r i p f l u i d back t o t h e sample p r i o r t o e x t r a c t i o n , and d i d not f i n d a s i g n i f i c a n t d i f f e r e n c e I n t h e amount o f e x t r a c t a b l e p r o t e i n s between i r r a d i a t e d meat and c o n t r o l samples. I n a d d i t i o n , t h e r e s u l t of e l e c t r o p h o r e t i c a n a l y s e s showed a d i s a p p e a r -ance of one band i n t h e e l e c t r o p h o r e t i c p a t t e r n o f t h e g l y c i n e - N a O H - s o l u b l e p r o t e i n e x t r a c t e d from t h e i r r a d i a t e d muscle. I t has been r e p o r t e d t h a t i r r a d i a t i o n - s t e r i l i z a t i o n r e s u l t s i n a f r a g m e n t a r y a c t i o n on t h e s t r u c t u r e o f t h e meat p r o t e i n s ( El - B a d a w i et a l , 1964 ), thus A n g l e m i e r et a l (1964) i n d i c a t e d t h a t t h e number of t h e e l e c t r o p h o r e t i f r a c t i o n s was e x p e c t e d t o i n c r e a s e r a t h e r t h a n t o d e c r e a s e o r not be a f f e c t e d . They e x p l a i n e d t h a t one p o s s i b i l i t y i s t h a t p r o t e i n fragments a r e h e l d t o g h t h e r by t h e hydrogen and/or t h e e l e c t r o s t a t i c bonds. The o t h e r p o s s i b i l i t y i s t h a t an i r r a d i a t i o n f r a g m e n t a t i o n e f f e c t i s e x e r t e d m a i n l y on t h e meat p r o t e i n not e x t r a c t e d by t h e glycine-NaOH b u f f e r . The l a t t e r e x p l a n a t i o n i s s u p p o r t e d by t h e r e s u l t s of Anderson and co-workers ( I 9 6 I ) . A n g l e m i e r et a l (1964) r e p o r t e d t h a t i r r a d i a -t i o n - s t e r i l i z a t i o n d e c r e a s e d t h e h y d r a t i o n of beef muscle i n t h e pH range 3'5 - 7.0 w i t h d e p r e s s i o n maximum nea r t h e i s o e l e c t r i c r e g i o n . These r e s u l t s a r e i n agreement w i t h L a w r i e et a l (I96I). A l t e r a t i o n o f t h e hydrogen o r e l e c -t r o s t a t i c bonds of a p r o t e i n s h o u l d have maximal e f f e c t on h y d r a t i o n around t h e i s o e l e c t r i c r e g i o n ( Hamm, i960 ). I r r a d i a t i o n may have some tendency t o t i g h t e n t h e meat p r o t e i n s t r u c t u r e by i n c r e a s i n g t h e number of t h e s e weak bonds. T h i s h y p o t h e s i s i s i n agreement w i t h i n f o r m a t i o n 11 p r e s e n t e d by Drake and G i f f e e (1957) on b o v i n e serum a l b u m i n . L a w r i e et a l (I96I) and B a t z e r et a l (1959) r e p o r t e d t h a t i r r a d i a t i o n caused an i n c r e a s e o f muscle pH. The i n c r e a s e o f muscle pH appears t o be due t o d e n a t u r a t i o n of t h e muscle p r o t e i n s , which i s known t o r e s u l t i n an i n c r e a s e i n pH ( B e n d a l l et a l t 1946, 19^7 ; N e u r a t h et a l , 195*+ )• E f f e c t of I r r a d i a t i o n on Amino A c i d s and P r o t e i n s The c h a r a c t e r i s t i c e f f e c t o f i o n i z i n g i r r a -d i a t i o n on amino a c i d s i s d e a m i n a t i o n ( I s e and Fos, 1955 >' P r o c t o r et a l , 1952 ). The p r i n c i p a l d e a m i n a t i o n p r o d u c t s of amino a c i d s a r e t h e c o r r e s p o n d i n g a l d e h y d e s and ammonia. The f o r m a t i o n o f ammonia from f r e e amino a c i d s has been s t u d i e d by K u z i n (1964). He i n d i c a t e d t h a t t h e alpha-amino group was most r e a d i l y deaminated, s i n c e i t was d i r e c t l y i n f l u e n c e d by t h e a d j a c e n t n e g a t i v e l y - c h a r g e d c a r b o x y l i c group, w h i l e t h e amino group i n t h e b e t a p o s i t i o n was a l m o s t t w i c e as r e s i s t a n t . The d e c o m p o s i t i o n of amino a c i d s c o u l d be enhanced by t h e . i n t r o d u c t i o n i n t o t h e m o l e c u l e of a second n e g a t i v e group such as t h e double bonds of t h e i m i -d a z o l e r i n g o f h i s t i d i n e o r t h e second c a r b o x y l i c group o f g l y c y l g l y c i n e . K u z i n a l s o i n d i c a t e d t h a t h i g h m o l e c u l a r weight p r o t e i n m o l e c u l e s c o n t a i n i n g t h e i r amino n i t r o g e n i n t h e form of e p s i l o n and gamma amino l y s i n e groups d i d not r e l e a s e ammonia t o any g r e a t e x t e n t upon i r r a d i a t i o n . Morgan (1958) r e p o r t e d t h a t amino a c i d s c o n t a i n i n g s u l f u r ( m e t h i o n i n e , c y s t i n e and c y s t e i n e ) and the r i n g - c o n t a i n i n g amino a c i d s ( h i s t i d i n e , h y d r o x y p r o l i n e , p h e n y l a l a n i n e , p r o l i n e , and t r y p t o p h a n e ) a r e e x t r e m e l y s e n s i t i v e t o i r r a d i a t i o n . S t e n s t r o m and Lohmann (1928, 1931) found t h a t d i l u t e s o l u t i o n s o f t y r o s i n e , t r y p t o p h a n e and c y s t e i n e were more s u s c e p t i b l e t o i r r a d i a t i o n - i n d u c e d d e c o m p o s i t i o n t h a n were more c o n c e n t r a t e d s o l u t i o n s . I t i s w e l l known t h a t p r o t e i n m o l e c u l e s a r e e l e c t r i c a l l y charged c o l l o i d a l p a r t i c l e s . T h e i r p r o p e r t i e s depend on t h e s u r f a c e p o t e n t i a l , on t h e s t a b i l i t y of t h e h y d r a t i o n l a y e r s s u r r o u n d i n g t h e m o l e c u l e , and on t h e n a t u r e of e l e c t r o l y t e s and c o l l o i d s of a n o n p r o t e i n n a t u r e which combine w i t h t h e p r o t e i n m o l e c u l e . When a p r o t e i n s o l u t i o n i s exposed t o i o n i z i n g r a d i a t i o n , d i r e c t i o n i z a t i o n o f the p r o t e i n m o l e c u l e and t h e e f f e c t o f H* and •OH r a d i c a l s may b r i n g about a change i n t h e magnitude o f i t s s u r f a c e p o t e n t i a l and t h u s cause d e n a t u r a t i o n o f t h e p r o t e i n . Hydrogen bonds between p e p t i d e c h a i n s p l a y an i m p o r t a n t r o l e i n m a i n t a i n i n g t h e s t r u c t u r e o f a p r o t e i n macromolecule and o n l y a s m a l l amount of energy ( 2 - 9 K c a l ) i s n e c e s s a r y t o d i s r u p t t h e s e bonds ( K u z i n , 1964 ). However, hydrogen bonds a r e e a s i l y formed. Only c o n s i d e r a b l e doses of i r r a d i a t i o n can d i s r u p t enough hydrogen bonds s u f f i c i e n t l y t o cause n o t i c a b l e changes of mac r o m o l e c u l a r s t r u c t u r e ( K u z i n , 1964 ). Peacocke and P r e s t o n (1958), Cox et a l (1955), a n d Lee (1951) suggested, on t h e b a s i s o f DNA t i t r a t i o n c u r v e s , t h a t under t h e i n f l u e n c e o f g a m m a - i r r a d i a t i o n t h e hydrogen bonds between t h e two n u c l e o t i d e c h a i n s were r u p t u r e d and sep-a r a t i o n of t h e c o i l s t o o k p l a c e . B u t l e r (1959) o b s e r v e d t h a t t h e s e p a r a t i o n o f t h e c h a i n s i s m a r k e d l y dependent on t h e c o n c e n t r a t i o n o f t h e NaCl s o l u t i o n i n which t h e DNA'is d i s s o l v e d d u r i n g i r r a d i a t i o n . DNA m o l e c u l e s a r e e x t r e m e l y l a r g e and a d i r e c t e f f e c t of i r r a d i a t i o n can not be e x c l u d e d ( K u z i n , 1964). However, i t has been shown t h a t i n d i l u t e s o l u t i o n s DNA i s much more r a d i o s e n s i t i v e ( Drew, 1955 ) t h a n i n t h e d r y s t a t e ( K u z i n , 1964 ). These o b s e r v a t i o n s i n d i c a t e t h a t t h e s p e c i f i c e f f i c i e n c y o f t h e i n d i r e c t e f f e c t of i r r a d i a t i o n on d i l u t e s o l u t i o n s o f p r o t e i n s i s much g r e a t e r t h a n t h a t of d i r e c t h i t o f t h e d i s s o l v e d m o l e c u l e s . B u t l e r (1950) r e p o r t e d t h a t t h e e f f i c i e n c y o f t h e i n d i r e c t e f f e c t i n s o l u t i o n s i s a p p r o x i m a t e l y t h e same w i t h i n a wide range of DNA c o n c e n t r a t i o n s . K u z i n (1964) r e p o r t e d t h a t when DNA s o l u t i o n s were i r r a d i a t e d , t h e r e was a s h a r p d e c r e a s e i n s p e c i f i c v i s c o s i t y i n d i c a t i n g a l o s s of m o l e c u l a r asymmetry. Changes i n t h e s t r u c t u r a l v i s c o s i t y of DNA a r e a f u n c t i o n o f t h e i r r a d i a t i o n dose. The l a t t e r a u t h o r e x p l a i n e d t h a t t h e d i s a p p e a r a n c e of t h e c h a r a c t e r i s t i c asymmetry c o u l d be due t o e i t h e r of two d i f f e r e n t p r o c e s s e s depending upon t h e c o n d i t i o n s of i r r a d i a t i o n . F i r s t , i t i s p o s s i b l e t h a t m o l e c u l a r d e p o l y m e r i z a t i o n w i t h d e c o m p o s i t i o n and s e p a r a t i o n of s y m m e t r i c a l fragments o c c u r r e d o r second, t h a t an a g g r e g a t i o n o f r o d - l i k e m o l e c u l e s a l o n g t h e i r l o n g a x i s might have t a k e n p l a c e and t h u s r e s u l t e d i n t h e f o r m a t i o n of a s y m m e t r i c a l conglomerate. A c c o r d i n g t o A l e x a n d e r ( 1 9 6 1 ) , when t h e n u c l e o t i d e c h a i n i s r u p t u r e d a f r e e t e r m i n a l groups appears which has t h e n a t u r e of a r a d i c a l and i s c a p a b l e o f f o r m i n g a " l i n k a g e ", c a u s i n g t h e a g g r e g a t i o n of t h e p r o t e i n m o l e c u l e . I n t h e p r e s e n c e o f oxygen, p e r o x i d e groups a r e formed on t h e a c t i v e ends so t h a t l i n k a g e s a r e not e s t a b l i s h e d w i t h t h e r e s u l t t h a t t h e m o l e c u l e i s degraded. K u z i n ( 1 9 6 4 ) r e p o r t e d t h a t myosin s o l u t i o n s a r e h i g h l y s e n s i t i v e t o i o n i z i n g i r r a d i a t i o n . Rhodes and S o u t h e r n ( 1 9 6 7 ) showed an i n c r e a s e o f t h e v i s c o s i t y of myosin s o l u t i o n ( 0 . 3 - 0 . 4 5 p r o t e i n i n 0.25M KC1 a t pH 7 . 0 ) a f t e r i r r a d i a t i o n under vacuum a t doses of 1 0 K r a d t o 1 5 0 K r a d . A f t e r 1 5 0 K r a d , s o l u t i o n s became g e l l e d . H i g h e r dose l e v e l s w i t h o u t r e s u l t i n g g e l a t i o n o f t h e p r o t e i n s o l u t i o n were made p o s s i b l e by i n c r e a s i n g t h e s a l t concen-t r a t i o n t o 0 . 5 M KC1. McArdle and D e s r o s i e r ( 1 9 5 5 ) o b s e r v e d s i g n i f i c a n t changes i n t h e p r o t e i n s t r u c t u r e s of c a s e i n and egg albumen a f t e r i r r a d i a t i o n . They r e p o r t e d t h a t a l t h o u g h t h e p a t t e r n of changes d i f f e r e d i n t h e s e two p r o t e i n s , t h e b u i l d up i n f r e e s u l f h y d r y l groups d e f i n i t e l y i n d i c a t e d t h a t t h e s u l f u r l i n k a g e s and hydrogen bonds were a l t e r e d , c a u s i n g m o l e c u l a r rearrangement. S i n c e t h e s e a u t h o r s d i d not observe an i n c r e a s e i n amino n i t r o g e n w i t h t h e s e m o l e c u l a r changes, t h e y assumed, t h a t t h e r e was v e r y l i t t l e a t t a c k upon t h e p e p t i d e l i n k a g e s . They a l s o compared t h e e l e c t r o p h o r e t i c p a t t e r n of n o n - i r r a d i a t e d s o l u t i o n s o f c a s e i n w i t h t h o s e i r r a d i a t e d a t a dose o f 1.5 x 10^ r e p . They r e p o r t e d t h a t t h e i r r a d i a t e d c a s e i n produced an e n t i r e l y new e l e c t r o p h o -r e t i c component d i f f e r i n g d i s t i n c t l y i n p a t t e r n and m o b i l i t y from t h e a l p h a and b e t a components found i n t h e n o n - i r r a d i a t e d c a s e i n . They d e s c r i b e d t h e changes i n t h e i r r a d i a t e d c a s e i n as t h o s e of m o l e c u l a r s p l i t t i n g f o l l o w e d by p o l y m e r i z a t i o n of t h e f r a c t i o n s t o cause an i n c r e a s e i n v i s c o s i t y . T h i s p a t t e r n of m o l e c u l a r m o d i f i c a t i o n resembles t h e d e s c r i p t i o n of t h e heat d e n a t u r a t i o n o f c a s e i n as r e p o r t e d by N e u r a t h and B a i l e y (195*0 i n which t h e m o l e c u l e s s p l i t , p o l y m e r i z e , and f i n a l l y c o a g u l a t e . I n t h e case of i r r a d i a t e d egg albumen s o l u t i o n , McArdle and C e s r o s i e r (1955) i n d i c a t e d t h a t m o l e c u l a r s p l i t t i n g a p p a r e n t l y d i d not o c c u r . However, t h e y o b s e r v e d a g r a d u a l change o f t h e egg albumen m o l e c u l e s , which gave r i s e t o an a s y m m e t r i c a l c o n f i g u r a t i o n and t h e r e b y caused an i n c r e a s e i n r e l a t i v e v i s c o s i t y . S i n c e t h e r a t e of i n c r e a s e i n r e l a t i v e v i s c o s i t y was s l o w and l i n e a r l y w i t h t h e i n c r e a s e of i r r a d i a t i o n dosage, t h e l a t t e r a u t h o r s c o n c l u d e d t h a t p o l y m e r i z a t i o n was not o c c u r i n g , a t l e a s t not a t a v e r y g r e a t r a t e which was t h e case f o r c a s e i n d u r i n g i r r a d i a t i o n - i n d u c e d p o l y m e r i z a t i o n p e r se. The d e n a t u r a t i o n b e h a v i o r of egg albumen caused by i r r a d i a t i o n on t h e t r a n s f o r m a t i o n of t h e g l o b u l a r form t o an asymme-t r i c a l m o l e c u l e s resembled t h a t produced by h e a t , except i n 16 heat d e n a t u r a t i o n , t h e g l o b u l a r m o l e c u l e were f u r t h e r p o l y m e r i z e d and c o a g u l a t e d ( N e u r a t h and B a i l e y , 195^ )• EXPERIMENTAL METHODS Source and Treatment o f Samples Mature t u r k e y s ( 2 0 - 2 4 weeks of age ) were d r e s s e d u s i n g commercial t e c h n i q u e s and t h e n f r o z e n and s t o r e d i n a - 23 °C f r e e z e r . The c a r c a s s e s were thawed, hand deboned and s e p a r a t e d i n t o l i g h t and dark meat p o r t i o n s . The l i g h t meat p o r t i o n was ground t w i c e t h r o u g h a 1/8-in p l a t e and mixed t h o r o u g h l y . A p p r o x i m a t e l y 260 grams o f t h e ground l i g h t meat was packed and s e a l e d i n a p o l y e t h y l e n e bag and h e l d a t - 23 °C u n t i l e x p eriments were performed. A scheme of t h e experiment i s shown i n F i g u r e 1. S a l t - S o l u b l e P r o t e i n s The p r o t e i n s e x t r a c t e d w i t h NaCl were p r e p a r e d by a method s i m i l a r t o t h a t of C a r p e n t e r and. S a f f l e (1964). F i f t y grams of meat were b l e n d e d f o r 1 minute w i t h 200 ml of jfo NaCl i n a Waring B l e n d e r . The s i d e s of t h e Bowl were swabbed and t h e m i x t u r e was a l l o w e d t o s t a n d f o r 3 minutes and t h e n b l e n d e d f o r 1 minute. A l l e x t r a c t i o n p r o c e d u r e s 17 Ground Turkey L i g h t Meat 1 I r r a d i a t i o n Add 3% NaCl s o l u t i o n and b l e n d i n a Waring B l e n d e r E x t r a c t i o n o f s-s-p D i l u t e t o ca 8 mg/ml Meat s l u r r y Measure pH i 1 1 Weigh 3»8 gm C e n t r i f u g e a t 16,300 x G I r r a d i a t i o n I Measure pH Sample A S u p e r n a t a n t Add 30 ml o f 3% HaCl s o l u t i o n Sample B Measure- D e t e r m i n - D i a l y s i s React ment of a t i o n of v i s c o s i t y e m u l s i f y i n g c a p a c i t y w i t h ANS Record t h e volume D i s c e l e c t r o p h o r e s i s D e t e r m i n a t i o n of e m u l s i f y i n g c a p a c i t y Raw e m u l s i o n D e t e r m i n a t i o n of s t a b i l i t y P i p e t t 25 ml i n t o K j e l d a h l f l a s k M i c r o s c o p i c photography Measure-ment of f l u o r e s -cence i n t e n s i t y Measurement of v i s c o s i t y D i g e s t i o n D e t e rm i na11on of p r o t e i n F i g . 1 Flow diagram o f e x p e r i m e n t a l p r o c e d u r e were done i n t h e c o l d room a t 4 °C. A weighed s l u r r y was t r a n s f e r r e d t o 250 ml c e n t r i f u g e t u b e and c e n t r i f u g e d a t 5 °C f o r 20 minutes a t 16,300 x G i n a S o r v a l l Superspeed RC2-3 a u t o m a t i c r e f r i g e r a t e d c e n t r i f u g e . A f t e r c e n t r i f u g a -t i o n t h e volume of s u p e r n a t a n t was r e c o r d e d and i t was t h e n f i l t e r e d t h r o u g h g l a s s wool. P r o t e i n was d e t e r m i n e d by t h e K j e l d a h l Method ( A.O.A.G., I965 ). P e r c e n t e x t r a c t a b l e p r o t e i n was c a l c u l a t e d as f o l l o w : (N)(V)(14) (6 .25) (10-3)(Va ) (Waj % E x t r a c t a b l e _ x 100$ p r o t e i n Weight o f t o t a l p r o t e i n (gm) Where N = N o r m a l i t y of HCl used f o r t i t r a t i o n . V = ml HCl used i n t i t r a t i o n . Va = ml s u p e r n a t a n t . Vb = ml s u p e r n a t a n t p i p e t t e d i n t o K j e l d a h l f l a s k . Wa = Weight of sample meat plus, t h e weight of Jfo NaCl s o l u t i o n . Wb = Weight of meat s l u r r y c e n t r i f u g e d . The f i l t e r e d s u p e r n a t a n t was f u r t h e r d i l u t e d t o about 8 mg/ml i n c o n c e n t r a t i o n w i t h 2>% NaCl s o l u t i o n a t 1 °C and t h e n i m m e d i a t e l y s u b j e c t e d t o gamma i r r a d i a t i o n , I r r a d i a t i o n The packaged ground l i g h t meat was thawed i n a c o l d room a t 1 C o v e r n i g h t and kept i n p l a s t i c t e s t t u b e s s e a l e d w i t h a s t o p p e r . The e x t r a c t e d s-s-p s o l u t i o n was kept i n a 250 ml p l a s t i c c o n t a i n e r s e a l e d w i t h a s t o p p e r . Samples were s u b j e c t e d t o gamma i r r a d i a t i o n a t a dose of 1, 2, 3, o r 4 Mrads i n a cobalt-60 s o u r c e . D u r i n g t h e e n t i r e i r r a d i a t i o n o p e r a t i o n , t h e samples were kept a t a c o n s t a n t t e m p e r a t u r e by p a c k i n g i n cr u s h e d i c e which was changed h o u r l y . Measurement of t h e V i s c o s i t y o f S a l t - S o l u b l e P r o t e i n s The v i s c o s i t y o f d i l u t e d s-s-p s o l u t i o n s was measured w i t h a Z e i t f u c h s Cross-Arm V i s c o m e t e r ( Ko. 0. 01 ) which i s O.38 mm i n d i a m e t e r and 210 mm i n l e n g t h . The v i s c o m e t e r was mounted i n a v e r t i c a l p o s i t i o n i n a g l a s s ice-xtfater b a t h . The t e m p e r a t u r e o f t h e i c e - w a t e r l n th e water b a t h was kept homogeneous by o p e r a t i n g a motor p r o p e l l e r i n s e r t i n g i n t h e i c e water. One ml of t h e sample s o l u t i o n was p i p e t t e d i n t o t h e c l e a n d r y v i s c o m e t e r t h r o u g h t h e f i l l i n g t ube and t h e sample a l l o w e d t o f l o w i n t o t h e h o r i z o n t a l c r o s s - a r m . A f t e r a 5 minute e q u i l i b r a t i o n p e r i o d ( 1 °C ), s u c t i o n was a p p l i e d t o t h e tube t o s t a r t t h e f l o w of sample s o l u t i o n t h r o u g h t h e s i p h o n and i n t o t h e c a p i l l a r y . Time of e f f l u x was r e c o r d e d . V i s c o s i t y was c a l c u l a t e d a c c o r d i n g t o A l e x a n d e r et a l (I96I) and A3TM (1958). 1. Atomic Energy of Canada L t d . Gamma C e l l 220. 20 pH Measurement The pH o f meat s l u r r i e s and e x t r a c t e d s-s-p s o l u t i o n s was measured w i t h a C o r n i n g Model 10 pH Meter a t a sample t e m p e r a t u r e of 4 °C. D i s c E l e c t r o p h o r e s i s The s-s-p of b o t h i r r a d i a t e d and u n i r r a d i a t e d samples were s e p a r a t e d by d i s c e l e c t r o p h o r e s i s a c c o r d i n g t h e method of C l a r k e (1964) i n which homogeneous rod-shaped p o l y a c r y l a m i d e g e l s were used. Samples were d i a l y z e d a g a i n s t d e i o n i z e d water i n a c o l d room a t 4 °C f o r 48 hours t o reduce t h e i o n i c s t r e n g t h of t h e sample and t h e n d i s s o l v e d i n 0.45 M T r i s - b u f f e r s o l u t i o n ( pH 8.1 ) c o n t a i n i n g u r e a ( 4M ) and m e r c a p t o e t h a n o l ( ca 1M ). An a l i q u o t of p r o t e i n s o l u t i o n c o n t a i n i n g about 5 mg p r o t e i n was a p p l i e d on t h e t o p of t h e homogeneous 7% g e l ( t h e c o n c e n t r a t i o n of u r e a i n t h e a c r y l a m i d e g e l was 4 M ). A c u r r e n t o f 5 ma p e r tube was a p p l i e d f o r about 1.5 hours w h i l e t h e l o w e r p a r t of t h e e l e c t r o p h o r e s i s b u f f e r s o l u t i o n was h e l d i n a i c e b a t h . A f t e r e l e c t r o p h o r e s i s , t h e p r o t e i n s i n t h e p o l y -a c r y l a m i d e g e l were s t a i n e d w i t h 1% amido b l a c k s o l u t i o n f o r 1/2 hour and t h e n d e - s t a i n e d i n 7% a c e t i c a c i d u n t i l t h e d a r k - c o l o u r e d p r o t e i n bands were a p p a r e n t . The g e l s were scanned on a chromoscan and t h e p o l y a c r y l a m i d e g e l p a t t e r n s were t r a c e d . 21 F l u o r e s c e n t Study o f t h e Hydroph o b i c E f f e c t o f S-S-P The c o n f o r m a t i o n a l changes of t h e i r r a d i a t e d s-s-p were s t u d i e d by i n t e r a c t i o n w i t h t h e f l u o r e s c e n t dye, ANS ( 8 - a n i l i n o - l - n a p h t h a l e n e s u l f o n a t e ) s i m i l a r t o t h e method of Cheung and M o r a l e s (I969). ANS i s one of s e v e r a l p o l y c y c l i c a r o m a t i c compounds which a r e e s s e n t i a l l y n o n f l u o r e s c e n t i n aqueous s o l u t i o n but become s t r o n g l y f l u o r e s c e n t upon combining w i t h c e r t a i n p r o t e i n s ( Weber and L a u r e n c e , 195^ )• F l u o r e s c e n c e measurement was performed on a r a t i o s p e c t r o f l u o r e m e t e r equipped w i t h a 150-W xenon lamp. The wavelength 38O mjjLwas used f o r e x c i t a t i o n and ^75 mjj,for e m i s s i o n . The p h o t o m u l t i p l i e r o u t p u t , F, was r e a d d i r e c t l y on a s e n s i t i v e g a l v a n o m e t e r and a l s o r e c o r d e d on a Moseley 7004A X-Y r e c o r d e r . A l l f l u o r e s c e n c e measure-ments were made i n 0.05 M phosphate b u f f e r ( pH 7.0 ). The i n t r i n s i c d i s s o c i a t i o n c o n s t a n t , K, was e s t i m a t e d by p l o t t i n g t h e e q u a t i o n o f 1 = * + * where F i s t h e r too roo D f l u o r e s c e n t i n t e n s i t y ; Fco i s t h e maximum p o s s i b l e f l u o -r e s c e n c e a t i n f i n i t i v e l y l a r g e dye c o n c e n t r a t i o n . D i s th e c o n c e n t r a t i o n of dye r a n g i n g from 0.6 x l O - ^ M t o 4.90 x 10~5 M. With a known v a l u e o f K, t h e number o f b i n d i n g s i t e s of t h e p r o t e i n , n, c o u l d be e s t i m a t e d by p l o t t i n g t h e e q u a t i o n of 2£ = 4 + JL- k where P i s t h e c o n c e n t r a t i o n F f n r P o f p r o t e i n ; £ i s t h e f l u o r e s c e n c e p e r s i t e . The c o n c e n t r a t i o n 22 of s-s-p was v a r i e d , from 0.13 x 10 - J M t o 1.28 x 10 I-I. E m u l s i f y i n g ; C a p a c i t y Both s-s-p s o l u t i o n s and meat s l u r r i e s were used t o measure t h e e m u l s i f y i n g c a p a c i t y o f t h e p r o t e i n i n a model system s i m i l a r t o t h a t r e p o r t e d by S w i f t et a l (1961). Sample A ( 30 ml of s-s-p e x t r a c t ) o r sample B ( 3 . 8 gm s l u r r y + 30 ml of 2>% NaCl s o l u t i o n ) was p l a c e d i n a Mason j a r a t t a c h e d on a Omni-mixer. An i n i t i a l 25 ml of c o t t o n s e e d o i l was added from a 250 ml b u r e t t h r o u g h Tygon t u b i n g i n t o t h e j a r and mixed w i t h t h e sample s o l u t i o n . F i g . 2 Arrangement of a p p a r a t u s f o r d e t e r m i n a t i o n of e m u l s i f y i n g c a p a c i t y . 23 T h i s m i x t u r e was b l e n d e d i m m e d i a t e l y f o r 3° seconds a t 11,200 o r 13,600 rpm t o f a c i l i t a t e t h e f o r m a t i o n of t h e e m u l s i o n . At t h i s t i m e more o i l was d e l i v e r e d , a t t h e r a t e of 1 ml p e r second, u n t i l t h e " b r e a k - p o i n t " o f t h e e m u l s i o n was o b s e r v e d as i n d i c a t e d by an a b r u p t phase t r a n s i t i o n , i . e . a sudden d e c r e a s e i n t h e v i s c o s i t y w i t h a r e s u l t i n g o i l - l i k e appearance. The volume of c o t t o n s e e d o i l added from t h e b u r e t ( an amount j u s t e x c e e d i n g t h e e m u l s i f y i n g c a p a c i t y of t h e meat p r o t e i n ) was r e a d d i r e c t l y from t h e g r a d u a t i o n s on t h e b u r e t . The e m u l s i f y i n g c a p a c i t y was e x p r e s s e d as m i l l i l i t e r s o f o i l e m u l s i f i e d by 100 mg o f p r o t e i n . I n o r d e r t o m i n i m i z e t h e e f f e c t o f f l o w due t o o i l column i n t h e b u r e t , each r u n was s t a r t e d from t h e same h e i g h t of o i l i n t h e b u r e t . The h e i g h t o f o i l i n t h e b u r e t was c o n t r o l e d by pumping t h e o i l from t h e b o t t l e and a u t o m a t i c a l l y s i p h o n i n g t h e excess o i l back t o t h e b o t t l e when t h e o i l l e v e l i n t h e b u r e t exceeded t h e s e l e c t e d maximum ( F i g . 2 ). A l l o f t h e samples i n t h e Mason j a r were kept i n c r u s h e d i c e t o m a i n t a i n a c o n s t a n t t e m p e r a t u r e a t 1 °C. The f i n a l t e m p e r a t u r e , o r end p o i n t t e m p e r a t u r e , was r e c o r d e d . S l i d e P r e p a r a t i o n The method used was a c o m b i n a t i o n o f t h a t o f S w i f t et a l (I96I) and Meyer et a l (1964). D u p l i c a t e s of raw e m u l s i o n were made by f o l l o w i n g t h e p r o c e d u r e f o r 24 e m u l s i o n s t a b i l i t y . The d u p l i c a t e s were mixed t h r o u g h l y i n t o one and t h e e m u l s i o n s were d i l u t e d w i t h 2 volumes of water. A p p r o x i m a t e l y 0.5 gm o f d i l u t e d e m u l s i o n was s p r e a d e v e n l y on a m i c r o s c o p e s l i d e and few drops of h e m a t o x y l i n s t a i n i n g s o l u t i o n were added. S l i d e s were p r e p a r e d and examined i n t h e c o l d room, and p h o t o m i c r o g r a p h s o f t h e s t a i n e d e m u l s i o n s were t a k e n w i t h i n f i v e minutes i n a W i l d Heerbrugg M i c r o s c o p e w i t h an A s a h i Pentax S p o t m a t i c Camera. Measurement of t h e V i s c o s i t y o f E m u l s i o n E m u l s i o n s were aged f o r 48 hours a t 4 °C b e f o r e t h e measurement of v i s c o s i t y . The v i s c o s i t y o f aged emul s i o n s were measured w i t h a Haake R o t o v i s c o V i s c o m e t e r , d e s c r i b e d by Van Wazer et a l (1963), a t e i g h t d i f f e r e n t -1 1 s h e a r r a t e s r a n g i n g from 32 sec t o I29 .5 sec u s i n g an MV I I I s p i n d l e . P r i o r t o measurement, each sample was s t i r r e d a t t h e shear r a t e of I29.5 s e c " ^ f o r t e n m i n u t e s . Sample t e m p e r a t u r e was m a i n t a i n e d a t 3 °C by c i r c u l a t e d i c e water t h r o u g h t h e water j a c k e t s u r r o u n d i n g t h e measuring head. Apparent v i s c o s i t y was c a l c u l a t e d by f i t t i n g t h e d a t a t o t h e Power Law e q u a t i o n ( Henderson and P e r r y , I966 ) t V = K 7 Where 7j i s apparent v i s c o s i t y i n c e n t i p o i s e , *)( i s s h e a r r a t e i n s e c - 1 and K ( c o n s i s t e n c y i n d e x ) and n ( f l o w b e h a v i o r i n d e x ) a r e c o n s t a n t s . 25 S t a b i l i t y of E m u l s i o n S t a b i l i t y of e m u l s i o n was d e t e r m i n e d f o r n o n - i r r a d i a t e d and i r r a d i a t e d s-s-p s o l u t i o n s mixed w i t h o i l by f o l l o w i n g t h e p r o c e d u r e used f o r e m u l s i f y i n g c a p a c i t y , except t h a t a p r e d e t e r m i n e d amount of o i l was added r a t h e r t h a n a d d i n g o i l u n t i l t h e e m u l s i o n broke. S t a b i l i t y was t h e n a s s e s s e d by t h e method of Meyer et a l (1964) w i t h minor m o d i f i c a t i o n s . A 25 gm a l i q u o t of t h e e m u l s i o n was p l a c e d i n a 50 ml p l a s t i c c e n t r i f u g e t u b e . These tubes were c e n t r i f u g e d f o r 5 minutes a t 1,000 x G and t h e n s u b j e c t e d t o a b o i l i n g water b a t h f o r 10 m i n u t e s . The r e n d e r e d f a t and j u i c e were dec a n t e d i n t o a g r a d u a t e d 15-ml c e n t r i f u g e tube and t h e volume of f a t and j u i c e r e c o r d e d . 26 RESULTS AND DISCUSSION E x t r a c t a b i l i t y T a b l e 1 i n d i c a t e s t h a t t h e r e was a de c r e a s e i n t h e amount of p r o t e i n c o n t a i n e d i n a 25-ml a l i q u o t of p i p e t t e d sample s o l u t i o n a f t e r i r r a d i a t i o n . The amount o f p r o t e i n d e c r e a s e d as i r r a d i a t i o n dose i n c r e a s e d from 0 t o 4.0 K r a d . I t has been shown t h a t i r r a d i a t i o n r e s u l t s i n a d e c r e a s e of water h o l d i n g c a p a c i t y o f f r e s h meat ( L a w r i e , 1966 ). I t i s apparent t h a t t h e amount o f e x t r a c t e d m o i s t u r e s h o u l d be t a k e n as one of t h e f a c t o r s i n t h e c a l c u l a t i o n of p e r c e n t e x t r a c t a b l e p r o t e i n from t h e t i s s u e . T a b l e 1 shows : T a b l e 1. E f f e c t of I r r a d i a t i o n of Turkey L i g h t Meat on t h e E x t r a c t a b i l i t y o f Meat P r o t e i n Dose of mg s-s-p p er ml of % e x t r a c t a b l e I r r a d i a t i o n 25 ml a l i q u o t s u p e r n a t a n t p r o t e i n C o n t r o l 586 a 126 29.03 a 1 Mrad 562 b 133 29.37 a 2 Mrad 539 c 139 29.45 a 3 Mrad 511 d 145 29.14 a 4 Mrad 501 e 148 29.16 a Means w i t h s u p e r s c r i p t s i n common a r e not s i g n i f i c a n t l y d i f f e r e n t a t t h e 5% l e v e l of p r o b a b i l i t y . 27 no s i g n i f i c a n t d i f f e r e n c e i n t h e p e r c e n t e x t r a c t a b l e p r o t e i n among t r e a t m e n t s . Thus, a d e c r e a s e i n t h e amount of p r o t e i n i n t h e a l i q u o t of p i p e t t e d sample s o l u t i o n i n t h e d i g e s t i o n f l a s k appears t o have been due t o a d i l u t i o n e f f e c t caused by t h e d e c r e a s e d water h o l d i n g c a p a c i t y o f t h e meat. T h e r e f o r e , i r r a d i a t i o n appears t o have no s i g n i f i c a n t e f f e c t on t h e e x t r a c t a b i l i t y o f meat p r o t e i n s p e r se. The amount of s-s-p e x t r a c t e d from t h e t u r k e y l i g h t meat was e s t i m a t e d t o be about 2<)% ( T a b l e 1 ) which was l o w e r t h a n t h e v a l u e of 35»1$ r e p o r t e d by Hudspeth and May (1967)• I n t h e i r sample p r e p a r a t i o n , t h e ground l i g h t meat was from t h e s l a u g h t e r e d t u r k e y c a r c a s s e s w h i l e i n t h i s i n v e s t i g a t i o n t h e meat was from f r o z e n t u r k e y c a r c a s s e s . S i n c e f r e e z i n g o f t h e meat a f t e r r i g o r m o r t i s causes a d e c r e a s e of t h e e x t r a c t a b i l i t y of t h e p r o t e i n ( 4 - 6;1> f o r beef muscle and 9% f o r cow meat ) a f t e r t h a w i n g ( T u r n e r and O l s o n , 1959 ; S a f f l e and G a l b r e a t h , 1964 ), t h e l o w e r p e r c e n t a g e of s-s-p e x t r a c t e d from t h e t i s s u e i n t h e c u r r e n t s t u d y i s u n d e r s t a n d a b l e . V i s c o s i t y o f S a l t - S o l u b l e - P r o t e i n E x t r a c t The v i s c o s i t y of t h e s-s-p s o l u t i o n d e c r e a s e d w i t h i n c r e a s i n g dose o f i r r a d i a t i o n up t o 2 Mrad and t h e n l e v e l e d o f f ( T a b l e 2 ). At an i r r a d i a t i o n dose o f 1 Mrad, t h e v i s c o s i t y of t h e s-s-p dropped 0.084 c e n t i p o i s e compared t o t h e c o n t r o l . At 2 Mrad, t h e v i s c o s i t y dropped an T a b l e 2. E f f e c t o f I r r a d i a t i o n o f S a l t - S o l u b l e -P r o t e i n E x t r a c t (7.8 mg/ml) on V i s c o s i t y Dose of I r r a d i a t i o n i V i s c o s i t y ( C e n t i p o i s e ) C o n t r o l 2 . l 5 9 a 1 Mrad 2.075 b 2 Mrad 2.032° 3 Mrad 2.037° 4 Mrad 2.025° 1 Means w i t h s u p e r s c r i p t s i n common a r e " n o t s i g n i f i c a n t l y d i f f e r e n t a t t h e l e v e l o f p r o b a b i l i t y . T a b l e 3. A n a l y s i s o f V a r i a n c e f o r Data of T a b l e 2 Showing t h e I s o l a t i o n of t h e L i n e a r , Q u a d r a t i c , C u b i c and Q u a r t i c Components of t h e Treatment Sum o f Square Source of V a r i a t i o n d. f . Sum o f Square Mean Square Treatments .02^9 .0062 L i n e a r 1 .01930 .01930 Q u a r d r a t i c 1 .00500 .00500 C u b i c 1 .00075 .00075 Q u a r t i c 1 .00002 .00002 E x p e r i m e n t a l E r r o r 5 .0001 .00002 T o t a l 9 .0250 a d d i t i o n a l 0.0^3 c e n t i p o i s e . From 2 Mrad t o 4 Mrad t h e r e was no s i g n i f i c a n t change i n v i s c o s i t y . The response c u r v e of v i s c o s i t y o f s-s-p s o l u t i o n v e r s u s dose o f i r r a d i a t i o n , as a n a l y z e d i n a c c o r d a n c e w i t h t h e method o f O s t l e (1956), appears t o be c u r v i l i n e a r w i t h t h e bes t f i t b e i n g o b t a i n e d w i t h t h e t h i r d degree p o l y n o m i a l ( c u b i c ) ( T a b l e 3 ). F i b r o u s p r o t e i n s e x t r a c t e d from p o s t - r i g o r meat w i t h n e u t r a l s a l t s o l u t i o n o f h i g h i o n i c s t r e n g t h a r e m a i n l y myosin, t r o p o m y o s i n and a c t o m y o s i n ( Neurath and B a i l e y , 195^ ; Davey and G i l b e r t , 1968 ). The e x i s t e n c e of f r e e a c t i n i n t h e e x t r a c t i s i n doubt ( S w i f t , 1965 ). Myosin and t r o p o m y o s i n e x i s t i n s o l u t i o n as h i g h l y a l p h a -h e l i c a l m o l e c u l e s and behave l i k e a symmetric r i g i d rods w i t h a common s t r u c t u r e of c o i l e d - c o i l c o n f o r m a t i o n which i s s i m i l a r t o t h a t o f t h e DNA m o l e c u l e ( Ingram, I965 ). A l e x a n d e r et a l (1959) r e p o r t e d t h a t upon i r r a d i a t i o n , t h e r e was a de c r e a s e i n t h e v i s c o s i t y o f DNA s o l u t i o n s . Peacocke and P r e s t o n (1953), Cox et a l (1955), and Lee (1951) s u g g e s t e d , on t h e b a s i s of DNA t i t r a t i o n c u r v e s , t h a t t h e hydrogen bonds between t h e two n u c l e o t i d e c h a i n s were r u p t u r e d under t h e i n f l u e n c e o f i r r a d i a t i o n , and s e p a r a t i o n of t h e c o i l s t o o k p l a c e . S t r u c h k o v et a l (1963) photographed a d e c o m p o s i t i o n of DNA from t h i c k r o d l i k e a g g r e g a t e s i n t o t h e t h r e a d l i k e m o l e c u l e s upon i r r a d i a t i o n . Doty (1957) r e p o r t e d t h a t i n d i l u t e s o l u t i o n such a l o n g t h r e a d l i k e m o l e c u l e may c o i l i n t o a b a l l . • S i m i l a r changes may have t a k e n p l a c e d u r i n g i r r a d i a t i o n o f t h e s a l t - s o l u b l e meat p r o t e i n s i n t h e c u r r e n t e xperiments and c o u l d account f o r t h e v i s c o s i t y change of th e s e s o l u t i o n s . The two p o s s i b i l i t i e s a r e : (1) A d i s -30 r u p t i o n of d o u b l e h e l i c e s , h e l d t o g e t h e r by hydrogen bonding, l e a d i n g t o a d e c r e a s e i n m o l e c u l a r w e i g h t , r e d u c t i o n i n t h e l e n g t h of t h e m o l e c u l e and a d e c r e a s e of v i s c o s i t y ; (2) D i s r u p t i o n of one h e l i x , which would make t h e m o l e c u l e more f l e x i b l e and r e s u l t i n t h e f o r m a t i o n o f a b a l l . The m o l e c u l a r weight does not change but v i s c o s i t y , drops and volume o c c u p i e d by t h e m o l e c u l e i n s o l u t i o n d i m i n i s h e s . When a l a r g e dose of i r r a d i a t i o n i s a p p l i e d , t h e changes i n t h e p r o t e i n a r e p r o b a b l y d e s c r i b e d b e s t by t h e f i r s t p r o p o s i t i o n . T h i s c o n t e n t i o n i s s u p p o r t e d by t h e f i n d i n g t h a t i r r a d i a t e d s-s-p s o l u t i o n s had l o w e r f r e e z i n g p o i n t s t h a n n o n - i r r a d i a t e d ones, i n d i c a t i n g an i n c r e a s e i n m o l a r i t y as a r e s u l t of i r r a d i a t i o n . A c c o r d i n g t o C a r p e n t e r and S a f f l e (1965), v i s c o s i t y change i n d i c a t e s a change of m o l e c u l a r shape which i s a s s o c i a t e d w i t h t h e e m u l s i f y i n g c a p a c i t y . A r e d u c t i o n of t h e l e n g t h o f m o l e c u l e s h o u l d d e c r e a s e i t s e m u l s i f y i n g c a p a c i t y . Hoxvever, our r e s u l t s demonstrated t h a t a d e c r e a s e i n t h e v i s c o s i t y of s-s-p s o l u t i o n s was r e l a t e d t o an i n c r e a s e i n e m u l s i f y i n g c a p a c i t y . The c o r r e l a t i o n c o e f f i c i e n t ( r ) was - 0.998. I t i s a p p a r e n t t h a t t h e s e changes can not be i n t e r p r e t e d i n terms of t h e shape of m o l e c u l e o n l y . Under c o n d i t i o n s s e v e r e enough t o b r i n g about s e p a r a t i o n of t h e p r o t e i n c h a i n s p e r s e , an i n c r e a s e i n m o l a r i t y c o u l d r e s u l t i n an i n c r e a s e i n e m u l s i f y i n g c a p a c i t y even though v i s c o s i t y would be e x p e c t e d t o d e c r e a s e . I n f a c t , t h e e x t e n t o f v i s c o s i t y d e c r e a s e p r o b a b l y i n d i c a t e s t h e amount 31 of protein chain separated under the influence of i r r a d i a t i o n . From the data i n table 4 i t i s evident that i r r a d i a t i o n of the meat or extracted s-s-p solution caused a r i s e i n pH. The pH r i s e i s a l i n e a r function of the dose of i r r a d i a t i o n . The rate of increase was very s l i g h t for the i r r a d i a t e d meat but was greater i n the i r r a d i a t e d s-s-p solutions. This difference may be explained by the fact that proteins i n the solution state are more susceptible to i r r a d i a t i o n due to a more profound i n d i r e c t effect ( Kuzin, 1964 ). The general r i s e i n pH suggests an accompanying decarboxylation of the amino acids of the proteins ( Green-stei n and Winitz, I96I )• Under the influence of a high Table 4. E f f e c t of I r r a d i a t i o n of Turkey Light Meat and of Salt-Soluble-Protein • Extract (7.8 mg/ml) on pH Dose of pH Ir r a d i a t i o n Meat Slurry S-s-p Extract Control 6.00 6.15 1 Mrad 6.03 6.50 2 Mrad 6.06 6.60 3 Mrad 6.08 6.70 4 Mrad 6.10 6.80 dose o f i r r a d i a t i o n , t h e e f f e c t o f d e c a r b o x y l a t i o n of s-s-p w i t h a pH r i s e may have brought about a f r a g m e n t a t i o n o f t h e p r o t e i n m o l e c u l e , l e a d i n g t o a d e c r e a s e i n m o l e c u l a r weight and i n v i s c o s i t y . The c o r r e l a t i o n c o e f f i c i e n t between pH and v i s c o s i t y o f s-s-p s o l u t i o n was - O.98. I t i s p r o b a b l e t o assume t h a t i n c r e a s e o f pH i n d i c a t e d , i n p a r t , t h e e x t e n t of f r a g m e n t a t i o n of t h e p r o t e i n m o l e c u l e t h a t would have been a s s o c i a t e d w i t h t h e d e c r e a s e d v i s c o s i t y and i n c r e a s e d m o l a r i t y o f t h e s o l u t i o n . D i s c E l e c t r o p h o r e t i c A n a l y s i s The e l e c t r o p h o r e t i c p a t t e r n o f t h e c o n t r o l sample of s-s-p i s g i v e n i n F i g u r e J. The seven d i s t i n c t peaks shoxm i n d i c a t e seven d i f f e r e n t p r o t e i n f r a c t i o n s , each h a v i n g a d i f f e r e n t r a t e o f m o b i l i t y . The p a t t e r n f o r t h e s-s-p s o l u t i o n i r r a d i a t e d a t 1 Mrad ( F i g . 4 ) shows a d e c r e a s e i n f r a c t i o n s 1 and 3 and a s l i g h t i n c r e a s e i n f r a c t i o n s 4 and 5-Upon i r r a d i a t i o n , p a r t of f r a c t i o n s 1 and 3 may have been fragmented r e s u l t i n g i n a change i n t h e n e t charge. Through t h e s e i v i n g e f f e c t o f t h e g e l , t h e f r a g -mented f r a c t i o n would move f a s t e r , p o s s i b l y w i t h t h e same m o b i l i t y as f r a c t i o n s 4 and 5» t h u s c a u s i n g an i n c r e a s e i n th e peaks c o r r e s p o n d i n g t o f r a c t i o n s 4 and 5' At an i r r a d i a t i o n dose of 2 Mrad ( F i g . 5 ), t h e d e c r e a s e i n p r o t e i n f r a c t i o n s 1 and 3 w i t h a c o r r e s p o n d i n g 33 i Pig. 3 Electrophoretic pattern of the salt-soluble proteins i r r a d i a t e d at 0 Mrad ( Control ). 34 F i g . 4 E l e c t r o p h o r e t i c p a t t e r n of t h e s a l t - s o l u b l e p r o t e i n s i r r a d i a t e d a t 1 Mrad. I F i g . 5 E l e c t r o p h o r e t i c p a t t e r n of t h e s a l t - s o l u b l e p r o t e i n s i r r a d i a t e d a t 2 Mrad. Fig. 6 Electrophoretic pattern of the salt-soluble proteins i r r a d i a t e d at 3 Mrad. Electrophoretic pattern of the salt-soluble proteins irradiated at 4 Mrad. increase i n f r a c t i o n s 4 and 5 continued to be evident, In addition, the resolution of the bands on the gel column became weaker and there was a tendency f o r fractions 1 and 3 to become more electronegative. At 3 Mrad ( F i g . 6 ), " an increase i n f r a c t i o n 2 was observed, accompanied by a decrease i n f r a c t i o n 1. At 4 Mrad ( F i g . 7 ) a wide spread peak, X, indicated that f r a c t i o n s 2 , 3 , 4 and 5 reached s i m i l a r rates of mobility and became Inseparable by t h i s technique. The increase i n the rate of mobility of the two main protein fractions i n polyacrylamide g e l , i n d i c a t i n g a fragmentation of the protein molecule, supports the postulated concept of an irradiation-induced separation of protein chains leading to a decrease i n v i s c o s i t y and an increase i n molarity. Fluorescent Study of the Hydrophobic E f f e c t of S-S-P . The data i n Table 5 indicate a progressive increase in the fluorescence Intensity (F) of the S-S-F-ANS system from 0 to 3 Mrad followed by a decline at 4 Mrad to a l e v e l approximating the 1 Mrad-treated samples. The i n t r i n s i c d i s s o c i a t i o n constant (K), a function of the reciprocal of fluorescence i n t e n s i t y (F), followed an inverse pattern. An increase i n fluorescence i n t e n s i t y (F) and a decrease i n K and n value ( compared to the control ) indicated s t r u c t u r a l changes of the s-s-p with an increase of h y d r o p h o b i c e f f e c t , I n t h e case o f e m u l s i f I c a t i o n , t h e h y d r o p h o b i c groups o f t h e s-s-p would o r i e n t t h e m s e l v e s toward t h e o i l phase and t h i s combined w i t h t h e apparent c o n f o r m a t i o n a l change would be e x p e c t e d t o l e a d t o an i n c r e a s e i n t h e e f f i c i e n c y o f s-s-p i n e m u l s i f i c a t i o n . At 4 Mrad l e v e l , t h e r e was a s l i g h t d e c r e a s e i n h y d r o p h o b i c e f f e c t i n t h e m o l e c u l e i n d i c a t e d by t h e ANS b i n d i n g . I n c o n j u n c t i o n w i t h t h e r e s u l t s of e l e c t r o p h o r e t i c a n a l y s i s , t h e s e f i n d i n g s c l e a r l y i n d i c a t e t h a t i r r a d i a t i o n a t a dose of 4 Mrad caused d r a s t i c changes i n t h e s-s-p. T a b l e 5. E f f e c t of I r r a d i a t i o n of S a l t - S o l u b l e P r o t e i n on t h e B i n d i n g of ANS Dose of I r r a d i a t i o n C o n t r o l 1 Mrad 2 Mrad 3 Mrad 4 Mrad 1 D i s t h e dye (ANS) c o n c e n t r a t i o n . D 1 = 0.6 x 10-5 M . D2 = 1.5 x 10"5 M" ; D^ = 2.3 x 10" 5 M ; D^ = 3.1 x 10" 5 M ; D^ = 4 .9 x 10-5 11, F v a l u e a t dye (ANS) cone, of ~1 D2 D3 DZj- D 5 (xlo -5) 4o 92 133. 167 235 1.56 11.4 59 133 172 208 270 0 .99 • 6.4 63 138 178 222 285 l . l 4 6 . 0 69 144 192 227 293 1.21 5.6 57 123 I67 200 263 1.97 6 .3 40 E m u l s i f y i n g C a p a c i t y The d a t a i n T a b l e 6 i n d i c a t e t h a t compared t o t h e c o n t r o l t h e r e was an i n c r e a s e i n t h e e m u l s i f y i n g c a p a c i t y of t u r k e y l i g h t meat i r r a d i a t e d a t t h e 1 o r 3 Mrad l e v e l . However, a t t h e 2 o r 4 Mrad l e v e l , t h e e m u l s i f y i n g c a p a c i t y was c o n s i s t e n t l y l e s s t h a n 'that o f t h e 1 o r 3 Mrad t r e a t m e n t and f r e q u e n t l y l e s s t h a n t h a t o f t h e c o n t r o l . The s t a n d a r d e r r o r of a t r e a t m e n t mean f o r each of t h e f i r s t t h r e e e x p e r i m e n t s was h i g h e r t h a n t h a t ' of t h e f o u r t h one. T h i s d i f f e r e n c e was due t o t h e f o r m a t i o n of somewhat r i g i d e m u l s i o n s which r e s i s t e d m i x i n g n e a r t h e " end p o i n t " i n t h e f i r s t t h r e e e x p e r i m e n t s as r e p o r t e d by S w i f t et a l (1961). However, t h i s was m i n i m i z e d by a s u i t a b l e adjustment on t h e d i l u t i o n of meat s l u r r y i n experiment 4, r e s u l t i n g i n a l o w e r s t a n d a r d e r r o r , and t h e r e f o r e h i g h e r s e n s i t i v i t y t o t r e a t m e n t e f f e c t s . Comparing t h e e m u l s i f y i n g c a p a c i t y o f t h e s-s-p w i t h t h a t of meat s l u r r y ( T a b l e 6 ) t h e l a t t e r showed a h i g h e r c a p a c i t y f o r e m u l s i f y i n g o i l . T h i s d i f f e r e n c e may be due t o t h e l o w e r c o n c e n t r a t i o n o f p r o t e i n i n t h e d i l u t e d meat s l u r r y ( Sample B, F i g . 1 ) compared t o t h e s-s-p e x t r a c t ( Sample A, F i g . 1 ). S e v e r a l a u t h o r s have r e p o r t e d t h e i m p o r t a n c e of t h e s-s-p f r a c t i o n i n meat e m u l s i o n f o r m a t i on. ( T u r n e r and Olson, 1959 ; S w i f t et a l , 1961 ; l i e g a r t y et a l , I963 ; C a r p e n t e r and S a f f l e , 1964 ) To e l u c i d a t e t h e i n f l u e n c e of T a b l e 6. E f f e c t o f I r r a d i a t i o n on t h e E m u l s i f y i n g C a p a c i t y o f Tur k e y L i g h t M e a t 1 Dose o f ml O i l 100 mg pe r S-S-P 2 ml 100 mg O i l p e r P r o t e i n - ^ I r r a d i a t i o n Exp. 1 Exp. 2 Exp. 3 Exp. 4 C o n t r o l 31.1 34.0a 52.5 a 4 7.8 a 1 Mrad 36.3 b 43.4 b 57.2b 49.8b 2 Mrad 30.4 a 34.4a 54.4 a b 44.3° 3 Mrad 35 . 2 a b 38 . 1 a b 56.6b 48.8d 4 Mrad 30.5 a 37.6 a b 49.5° 46.8e (± 1 .055)N± 1.04l)^(± o.728)4(+ 0.309)^ Means w i t h s u p e r s c r i p t s i n common a r e not s i g n i f i c a n t l y d i f f e r e n t a t t h e $% l e v e l of p r o b a b i l i t y . 1. V a l u e s were t h e average o f f i v e r e p l i c a t e s . Speed of m i x i n g was 11,200 rpm f o r a l l e x p e r i m e n t s . The f i n a l t e m p e r a t u r e of t h e e m u l s i o n was 19 + 1 °C. 2. E m u l s i f y i n g c a p a c i t y was de t e r m i n e d from e x t r a c t e d s-s-p s o l u t i o n . 3. E m u l s i f y i n g c a p a c i t y was de t e r m i n e d from meat s l u r r y . 4„ S t a n d a r d e r r o r of a t r e a t m e n t mean. i r r a d i a t i o n on t h e f u n c t i o n a l p r o p e r t i e s o f t h i s p r o t e i n f r a c t i o n as r e f l e c t e d by e m u l s i f y i n g c a p a c i t y , t h e s-s-p f r a c t i o n was e x t r a c t e d from t h e t i s s u e and s u b j e c t e d t o gamma i r r a d i a t i o n . I n p r e l i m i n a r y t e s t s i t was found t h a t e m u l s i o n f o r m a t i o n and breakdown i n t h e model system was most e a s i l y o b s e r v e d w i t h a p r o t e i n c o n c e n t r a t i o n o f about 8-10 mg/ml of s-s-p. T h e r e f o r e , c o n c e n t r a t i o n s of s-s-p c l o s e t o t h i s range were used i n subsequent e x p e r i m e n t s . There x^ere s m a l l but s i g n i f i c a n t i n c r e a s e s i n t h e e m u l s i f y i n g c a p a c i t y o f s-s-p s o l u t i o n w i t h i n c r e a s -i n g dose of i r r a d i a t i o n up t o 2 Mrad .( T a b l e 7> Exp. 3 )• No f u r t h e r s i g n i f i c a n t i n c r e a s e was n o t e d from 2 t o 4 Mrad. Exp e r i m e n t s 1 and 2 i n which a s l i g h t l y r i g i d e m u l s i o n formed because of t h e l o w e r speed o f m i x i n g , t h e system s e n s i t i v i t y was l o w e r and s i g n i f i c a n t d i f f e r e n c e s among t r e a t m e n t s were not ob s e r v e d ( T a b l e 7» Exp. 1 & 2 ). R e s u l t s of e l e c t r o p h o r e s i s , f l u o r e s c e n t s t u d y and v i s c o s i t y measurement on t h e i r r a d i a t e d s-s-p, r e v e a l e d t h a t t h e e f f e c t o f i r r a d i a t i o n on s-s-p was p o s s i b l y t o s e p a r a t e t h e p r o t e i n c h a i n w i t h a r e s u l t i n g i n c r e a s e i n th e m o l a r i t y o f t h e p r o t e i n s o l u t i o n . I t a l s o r e s u l t e d i n c o n f o r m a t i o n a l changes of t h e s-s-p w i t h i n c r e a s e d h y d r o -p h o b i c e f f e c t s i n a l l t h e t r e a t m e n t s except t h e 4 Mrad dose. Both of t h e two s t r u c t u r a l changes i n t h e s-s-p have been p o s t u l a t e d t o i n c r e a s e t h e e f f i c i e n c y o f e m u l s i f i c a t i o n p e r se. However, i n c r e a s i n g t h e c o n c e n t r a t i o n of e m u l s i f i e r has been r e p o r t e d t o d e c r e a s e p a r t i c l e s i z e o f t h e e m u l s i o n ( Bennett et a l , 1968 ) by c r e a t i n g more s u r f a c e a r e a and t o i n c r e a s e t h e p r o t e i n r e q u i r e m e n t a t t h e i n t e r f a c e . T h i s l a t t e r f i n d i n g may account f o r t h e r e l a t i v e l y s m a l l i n c r e a s e i n e m u l s i f y i n g c a p a c i t y o b s e r v e d f o r t h e i r r a d i a t e d samples. I n a d d i t i o n , t h e d e c r e a s e d h y d r o p h o b i c e f f e c t o f t h e 4 Mrad t r e a t e d samples would t e n d t o dep r e s s t h e i r e m u l s i f y i n g c a p a c i t y . I r r a d i a t i o n may have a f f e c t e d p r o t e i n s t o a l e s s e r e x t e n t t h a n t h e e x t r a c t e d p r o t e i n s o l u t i o n s because t h e i n d i r e c t e f f e c t would be l e s s s e v e r e i n t h e former. T a b l e 7. E f f e c t o f I r r a d i a t i o n of S-S-P E x t r a c t (7.8 mg/ml) on E m u l s i f y i n g C a p a c i t y ! Dose of m l 0 1 1 p e r IOC mg s-s-p I r r a d i a t i o n Exp. 1 Exp. 2 Exp. 3 C o n t r o l 35.5 s 34.7 a 31. l a 1 Mrad 37. 2 a 35. l a 33. l b 2 Mrad 36.4 a 34. o a 3*J-.1C 3 Mrad 35.2 a 34.5 a 34.0° 4 Mrad 35.6 a 34.5 a 34.4 C (± 0.616) 2 (± 0.512) 2 (± 0.279) 2 Mean w i t h s u p e r s c r i p t s i n common a r e not s i g n i f i c a n t l y d i f f e r e n t a t t h e 5% l e v e l of p r o b a b i l i t y . 1. V a l u e s were t h e average of f i v e r e p l i c a t e s . Speed of m i x i n g was 11,200 rpm f o r Experiments 1 and 2, and 13,600 rpm f o r Experiment 3-The f i n a l t e m p e r a t u r e o f t h e e m u l s i o n was 19 ± 1 °C. 2. S t a n d a r d e r r o r of a t r e a t m e n t mean. I r r a d i a t i o n o f meat samples a t t h e 1 Mrad l e v e l may have r e s u l t e d i n o n l y a c o n f o r m a t i o n a l change o f t h e p r o t e i n s , vri-th an i n c r e a s e i n t h e number of h y d r o p h o b i c r e g i o n s c o n d u c i v e t o i n t e r a c t i o n w i t h o i l and a c o r r e s p o n d i n g i n c r e a s e t h e amount of o i l a b l e t o be e m u l s i f i e d . With an I n c r e a s e i n dose of i r r a d i a t i o n t o 2 Mrad, one h e l i x of t h e s-s-p may have s t a r t e d t o u n c o i l , t h u s making t h e m o l e c u l e f l e x i b l e enough t o cause a d e c r e a s e i n t h e p a r t i c l e s i z e of t h e e m u l s i o n . The d e c r e a s e d p a r t i c l e s i z e would i n c r e a s e t h e s u r f a c e a r e a of t h e o i l t o be e m u l s i f i e d by' a l i m i t i n g amount of p r o t e i n and r e s u l t i n a d e c r e a s e i n t h e e m u l s i f y i n g c a p a c i t y , At t h e 3 Mrad l e v e l , c h a i n sep-a r a t i o n of t h e s-s-p might have o c c u r r e d . T h i s would have caused an i n c r e a s e i n t h e c o n c e n t r a t i o n o f e m u l s i f ! e r xvhich would s a t i s f y t h e a d d i t i o n a l r e q u i r e m e n t s f o r p r o t e i n caused by t h e i n c r e a s e d s u r f a c e a r e a o f o i l d r o p l e t s . I n a d d i t i o n , t h e i n c r e a s e d h y d r o p h o b i c e f f e c t p r o b a b l y c o n t r i -b u ted t o t h e o v e r a l l i n c r e a s e i n e m u l s i f y i n g c a p a c i t y compared t o t h e c o n t r o l . A t t h e 4 Mrad l e v e l , t h e d e c r e a s e i n e m u l s i f y i n g c a p a c i t y might have been due t o a d e c r e a s e d h y d r o p h o b i c e f f e c t o f s-s-p. M i c r o s c o p i c E x a m i n a t i o n of t h e E m u l s i o n E m u l s i o n s were made w i t h 30 nil s-s-p e x t r a c t (7-8 mg/ml) and 65 ml of o i l . ( The em u l s i o n breakdown p o i n t f o r t h e c o n t r o l and i r r a d i a t e d s-s-p ranged from 73 ml t o 81 45 Each o f t h e e m u l s i o n made from I r r a d i a t e d s-s-p had a v i s i b l y s m a l l e r p a r t i c l e s i z e t h a n t h e c o r r e s -ponding c o n t r o l e m u l s i o n s ( P i g . 8 ). The de c r e a s e i n p a r t i c l e s i z e of t h e e m u l s i o n appeared t o be a f u n c t i o n o f close of i r r a d i a t i o n up t o t h e 3 Mrad l e v e l . The p a r t i c l e s i z e s o f t h e e m u l s i o n s from t h e samples which had r e c e i v e d 3 o r 4 Mrad were i n d i s t i n g u i s h a b l e ( F i g . 8, D & E ). T h i s g e n e r a l d e c r e a s e i n p a r t i c l e s i z e w i t h i n c r e a s i n g i r r a d i a t i o n dose s u p p o r t s t h e i r r a d i a t i o n - i n d u c e d c h a i n s e p a r a t i o n t h e o r y o f Peacocke and P r e s t o n (1958), Cox et a l (1955) and Lee (1951), w i t h a t t e n d a n t i n c r e a s e s i n m o l a r i t y and e m u l s i f y i n g e f f i c i e n c y o f t h e p r o t e i n . I n a d d i t i o n , on t h e b a s i s o f t h e i n c r e a s e d h y d r o p h o b i c e f f e c t of i r r a -d i a t e d samples, t h e s e p a r a t e d s-s-p c h a i n would become o r i e n t e d i n a c o n f o r m a t i o n f a v o r i n g i n t e r a c t i o n w i t h t h e o i l phase, c o n t r i b u t i n g t o t h e i n c r e a s e i n e f f i c i e n c y o f th e s-s-p and t o t h e d e c r e a s e i n p a r t i c l e s i z e . V i s c o s i t y o f Em u l s i o n The r h e o l o g y of emuls i o n s has been s t u d i e d by s e v e r a l workers and t h e y have been r e p o r t e d t o behave as a non-Newtonian f l u i d ( Van den Tempel, 19^3 » Bennett et a l , 1968 ). i . e . t h e apparent v i s c o s i t y i s not c o n s t a n t o v e r a range of she a r r a t e s . Apparent v i s c o s i t y d e c r e a s e s w i t h i n c r e a s i n g s hear r a t e . The p r e s e n t d a t a were d e t e r -— 1 • mined over a range of she a r r a t e from 32 sec t o 129.5 sec 4 7 T a b l e 8. R h e o l o g i c a l P arameters f o r E m u l s i o n s Formed From C o n t r o l and I r r a d i a t e d S-S-P E x t r a c t s and R e s u l t s o f t h e S t a t i s t i c a l A n a l y s i s o f th e L e a s t - S q u a r e s F i t o f t h e Data t o t h e Power Law E q u a t i o n . Dose of o ji I r r a d i a t i o n K 2 n S.E.Y.^ r d.f . 5 C o n t r o l 3.33 a P.5U 0.0105 -0.999 15 1 Mrad 3.71 b 0.388 0.0263 -0.997 15 2 Mrad 3.84° 0.353 0.0423 -0.99^ 15 3 Mrad 3.86° 0.351 0.0349 -0.996 15 4 Mrad 3.89° 0.327 0.0234 -O.998 15 Means w i t h s u p e r s c r i p t s i n common a r e not s i g n i f i c a n t l y d i f f e r e n t a t t h e 5% l e v e l o f p r o b a b i l i t y . 1. C o n s i s t e n c y i n d e x ( c e n t i p o i s e ) ; 2. Flow b e h a v i o r i n d e x ; 3« S t a n d a r d e r r o r o f e s t i m a t e ; 4. C o r r e l a t i o n c o e f f i c i e n t 5 5« Degrees of freedom. and a p p a r e n t v i s c o s i t y c a l c u l a t e d by f i t t i n g t h e d a t a t o th e Power Law e q u a t i o n , 7} ^ V**"1 ( F 1 S « 9 )• The r e s u l t s ( T a b l e 8 ) i n d i c a t e t h a t t h e c o n s i s t e n c y i n d e x ( K ) , which i s a r e f l e c t i o n o f t h e v i s c o s i t y o f e m u l s i o n s , i n c r e a s e d c u r v i l i n e a r l y as i r r a d i a t i o n dose i n c r e a s e d from 0 t o 4 Mrad. The K v a l u e i n c r e a s e d s i g n i -f i c a n t l y ( p^0.05 ) w i t h each i n c r e a s e i n dose o f i r r a d i a t i o n up t o 2 Mrad. Subsequent i n c r e a s e s i n K v a l u e were non-s i g n i f i c a n t . I t i s e v i d e n t from t h e l e a s t - s q u a r e s f i t of th e d a t a t o t h e Power Law e q u a t i o n ( F i g . 9 ) t h a t t h e r a t e of d e c r e a s e i n apparent v i s c o s i t y w i t h i n c r e a s i n g r a t e o f I I I I 2 0.6 1.0 1.4 1.8 LOG t F i g . 9 Apparent v i s c o s i t y - s h e a r r a t e r e l a t i o n s f o r e m u l s i o n s . ( R e s u l t s o f t h e s t a t i s t i c a l a n a l y s i s o f t h e l e a s t - s q u a r e f i t of t h e d a t a t o t h e Power L a w e q u a t i o n i s shown i n T a b l e 8 ). ^ 9 s h e a r was g r e a t e r f o r t h e I r r a d i a t e d samples t h a n f o r th e c o n t r o l s . A c c o r d i n g t o t h e m i c r o s c o p i c f i n d i n g , i r r a -d i a t e d samples p o s s e s s e d s m a l l e r p a r t i c l e s i z e s t h a n t h e c o n t r o l and t h u s an i n c r e a s e i n v i s c o s i t y c o u l d be e x p e c t e d . S t a b i l i t y o f E m u l s i o n The s t a b i l i t y o f em u l s i o n s made from i r r a d i a t e d samples were s i g n i f i c a n t l y ( p« 0 . 0 5 ) more s t a b l e t h a n t h e c o n t r o l as judged by t h e volume of o i l r e l e a s e d ( T a b l e 9 )• No s i g n i f i c a n t d i f f e r e n c e s were found among t h e I r r a d i a t e d samples. A s i g n i f i c a n t ( p ^ 0 . 0 5 ) and p o s i t i v e c o r r e l a t i o n was found between v i s c o s i t y and s t a b i l i t y ( ml of o i l r e l e a s e d ) of t h e e m u l s i o n ( r = + 0 . 9 3 i n = 1 0 ). T h i s f i n d i n g a g r e e s T a b l e 9 . E f f e c t of I r r a d i a t i o n o f S-S-F E x t r a c t s on t h e S t a b i l i t y o f Formed E m u l s i o n s 1 Dose of O i l R e l e a s e d J u i c e R e l e a s e d I r r a d i a t i o n ( ml ) ( ml ) C o n t r o l 2 . 6 5 a 5,65s 1 Mrad 0 . 3 5 b 5 - 7 0 a 2 Mrad 0 . 2 0 b 5 . 5 0 a 3 Mrad o . l 3 b 5 . 2 5 a 4 Mrad 0 . 2 0 b 5 . i o a Means w i t h s u p e r s c r i p t s i n common a r e not s i g n i f i c a n t l y d i f f e r e n t a t t h e . l e v e l of p r o b a b i l i t y . 1. 6 5 ml of o i l was added t o each of t h e samples. w i t h t h e p r e v i o u s l y r e p o r t e d i n c r e a s e i n t h e s t a b i l i t y of e m u l s i o n w i t h i n c r e a s i n g v i s c o s i t y . No s i g n i f i c a n t ( p*0.05 ) d i f f e r e n c e s were found among t r e a t m e n t means i n t h e amount of j u i c e r e l e a s e d from t h e e m u l s i o n s . These f i n d i n g s suggest t h a t t h e i r r a -d i a t i o n - i n d u c e d i n c r e a s e i n e m u l s i f y i n g e f f i c i e n c y may have been a s s o c i a t e d w i t h an i n c r e a s e i n h y d r o p h o b i c e f f e c t o f t h e s-s-p w i t h t h e h y d r o p h o b i c groups p r e f e r e n t i a l l y s t a b i l i z i n g t h e o i l phase. SUMMARY The e f f e c t o f gamma i r r a d i a t i o n on t h e e m u l s i f y i n g c a p a c i t y o f t u r k e y l i g h t meat was s t u d i e d i n a model system. A change of e m u l s i f y i n g c a p a c i t y due t o t h e changes of f u n c t i o n a l c a p a b i l i t i e s of s-s-p were s t u d i e d on t h e i r r a d i a t e d s-s-p e x t r a c t by d i s c e l e c t r o -p h o r e s i s , v i s c o m e t r y , f l u o r e s c e n c e s p e c t r o s c o p y and measurement o f pH. The formed e m u l s i o n s were t a k e n f o r e x a m i n a t i o n of t h e p a r t i c l e s i z e under t h e m i c r o s c o p e , measurement of t h e v i s c o s i t y w i t h a Haake R o t o v i s c o V i s c o m e t e r , and f o r t h e d e t e r m i n a t i o n of t h e s t a b i l i t y by a method of c e n t r i f u g a t i o n and c o o k i n g . , I r r a d i a t i o n o f t u r k e y meat a t doses of 1 o r 3 Mrad i n c r e a s e d t h e e m u l s i f y i n g c a p a c i t y o f t h e t i s s u e but doses of 2 o r 4 Mrad d e c r e a s e d c a p a c i t y r e l a t i v e t o an u n i r r a d i a t e d c o n t r o l . I r r a d i a t i o n had no e f f e c t on t h e e x t r a c t a b i l i t y o f s-s-p. The e m u l s i f y i n g c a p a c i t y of i r r a d i a t e d s-s-p e x t r a c t i n c r e a s e d s i g n i f i c a n t l y ( p«:0.05 ) and v i s c o s i t y d e c r e a s e d s i g n i f i c a n t l y ( p^0.05 ) w i t h i n c r e a s i n g dose of i r r a d i a t i o n from 0 t o 2 Mrad. Doses o f 3 o r 4 Mrad f a i l e d t o produce f u r t h e r s i g n i f i c a n t change i n e i t h e r v a r i a b l e . I r r a d i a t i o n o f t h e s-s-p e x t r a c t a l s o r e s u l t e d i n a d e c r e a s e i n p a r t i c l e s i z e of t h e e m u l s i o n ; an i n c r e a s e i n v i s c o s i t y o f t h e e m u l s i o n ; an i n c r e a s e o f h y d r o p h o b i c e f f e c t i n t h e s-s-p m o l e c u l e ; an i n c r e a s e i n t h e e l e c t r o p h o r e t i c m o b i l i t y o f t h e two main p r o t e i n f r a c t i o n s on p o l y a c r y l a m i d e g e l ; an i n c r e a s e i n pH ; and an i n c r e a s e i n t h e s t a b i l i t y o f e m u l s i o n s judged on t h e b a s i s of volume o f o i l i n t h e s u p e r n a t a n t a f t e r c e n t r i f u -g a t i o n and c o o k i n g . BIBLIOGRAPHY 52 A l e x a n d e r , P. I96I. I n t h e book " The i n i t i a l e f f e c t s of i o n i z i n g r a d i a t i o n s on c e l l s ", p.l4. London. A l e x a n d e r , P., and B l o c k , R.J. I96I. A l a b o r a t o r y manual of a n a l y t i c a l methods of p r o t e i n c h e m i s t r y , i n c l u d i n g p o l y p e p t i d e s . V o l . 3- D e t e r m i n a t i o n of t h e s i z e and shape of p r o t e i n m o l e c u l e s , pp. 173-191« New York Pergamon P r e s s . A l e x a n d e r , P., L e t t , J.T., Moroson, H., and S t a c e y , K.A. 1959. Immediate and low l e v e l e f f e c t s of i o n i z i n g r a d i a t i o n s . A n g l e m i e r , A.F., E l - B a d a w i , A.A., and C a i n , R.F. 1964. E f f e c t o f i r r a d i a t i o n and p r e - i r r a d i a t l o n t r e a t m e n t s on beef muscle p r o t e i n s . J . Food S c i . 29 : 837-842. A.O.A.C. 1965. O f f i c i a l methods of a n a l y s i s . 10th ed. A s s o c . of O f f i c i a l A g r i c . C h e m i s t s , Washington, D. C. A.S.T.M. 1958. ASTM s t a n d a r d s on p e t r o l e u m p r o d u c t s and l u b r i c a n t s . A m e rican S o c i e t y f o r T e s t i n g M a t e r i a l s . B a t z e r , O.F., S l i w i n s k i , R.A., Chang, L., P l h , K., Fox, J . B . J r . , Doty, D.M., P e a r s o n , A.M., and Spooner, M.E. 1959' Some f a c t o r s i n f l u c i n g r a d i a t i o n i n d u c e d c h e m i c a l changes i n raw beef. Food T e c h n o l . 13 s 501-508. Becher, P. 1965' E m u l s i o n s s Theory and p r a c t i c e . 2nd. R e i n h o l d P u b l i s h i n g Corp., New York. B e n d a l l , J.R. 1946. The e f f e c t of c o o k i n g on t h e c r e a t i n e -c r e a t i n i n e , phosphorous, n i t r o g e n , and pH v a l u e s of raw l e a n beef. J . Soc. chem. I n d . , London, 65 5 226-230. B e n d a l l , J.R. 1947. E f f e c t o f d e n a t u r a t i o n on t h e base-b i n d i n g c a p a c i t y o f beef-muscle p r e s s j u i c e . P r o c . r o y . s o c . ( London ) 3, 134 : 272-282. B e n d a l l , J.R. 1969. I n t h e book " M u s c l e s , m o l e c u l e s and movement ", p. 6. Heinemann E d u c a t i o n a l Books L t d . , London. 5 J B e n n e t t , H., B i s h o p , J . L . , and W u l f i n g h o f f , M.F. 1968. P r a c t i c a l e m u l s i o n s . V o l . I . Ch e m i c a l P u b l i s h i n g Company, I n c . , New York. B o r c h a r t , L . L . , G r e a s e r , M.L., Bard , J.C., Cassens, R.G., and B r i s k e y , E . J . I967. E l e c t r o n m i c r o s c o p y of a meat e m u l s i o n . J . Pood S c i . 32 : 4 1 9 - 4 2 1 . B u t l e r , J.A.V., and S m i t h , K.A. 1950. D e g r a d a t i o n o f d e s o x y r l b o n u c l e i c a c i d by f r e e r a d i c a l s . N a t u r e 165 : 847-848. B u t l e r , J.A.V. 1959* Changes i n d u c e d i n n u c l e i c a c i d s by i o n i z i n g r a d i a t i o n s and c h e m i c a l s . R a d i a t i o n R e s e a r c h , S u p p l . 1, 4o3-4l6. C a r p e n t e r , J.A., and S a f f l e , R.L. 1964. A s i m p l e method of e s t i m a t i n g t h e e m u l s i f y i n g c a p a c i t y o f v a r i o u s sausage meats. J . Food S c i . 29 : 77^-781. C a r p e n t e r , J.A., and S a f f l e , R.L. I965. Some p h y s i c a l and c h e m i c a l f a c t o r s a f f e c t i n g t h e e m u l s i f y i n g c a p a c i t y of meat p r o t e i n e x t r a c t s . Food T e c h n o l . 19 (10) t I I I - I I 5 . Cheung, H.C, and M o r a l e s , M.F. I969. S t u d i e s of myosin c o n f o r m a t i o n by f l u o r e s c e n t t e c h n i q u e s . B i o c h e m i s t r y V o l . 8, No. 5 1 2 1 7 7 - 2 1 8 2 . C l a r k e , J.T. 1964. S i m p l i f i e d " D i s c " ( p o l y a c r y l a m l d e g e l ) e l e c t r o p h o r e s i s . New York Academy o f S c i e n c e s , A n n a l s 121 : 4 2 8-436. C l a y t o n , W. 195^. The t h e o r y of emuls i o n s and t h e i r t e c h n i c a l t r e a t m e n t . B l a k i s t o n Co., New York. C o l e b y , B., Ingram, M., Rhodes, D.N., and Shepherd, H.J. 1962. The i r r a d i a t i o n p r e s e r v a t i o n of pork sausages. J . S c i . Food A g r i c . , 13 * 628-633. Cox, R.A., Overend, W.G., Peacocke, A.R., and W i l s o n , S. 1955* E f f e c t s o f gamma-rays on s o l u t i o n s o f sodium d e o x y r i b o n u c l e a t e . N a t u r e I76 : 919-921. Davey, C L . , and G i l b e r t , K.V. I968. S t u d i e s i n meat t e n d e r n e s s . 6. The n a t u r e . o f m y o f i b r i l l a r p r o t e i n s e x t r a c t e d from meat d u r i n g a g i n g . J . F o o d S c i . 33 : 343-348. Doty, D.M., B a t z e r , O . F . , Fox, J . B . J r . , S l i w i n s k i , R.A., W i t t i n g , L.A., and S c h w e i g e r t , B.S. 1958. Chemical changes i n meat i n d u c e d b y gamma i r r a d i a t i o n . U.N. G e n e r a l Assembly. Second U n i t e d N a t i o n s I n t e r n a t i o n a l C o n f erences on t h e P e a c e f u l Uses of Atomic Energy : P r o c e e d i n g s . V o l . 27 : 4l4_4l7. ( A/COKF. 15/1, Vol.2? ) Doty, P. 1957. The p h y s i c a l c h e m i s t r y of d e o x y r i b o n u c l e i c a c i d . J . C e l l u l a r Compar. P h y s i o l . 4q 2 7 - 5 7 . Drew, R.M. 1955* Gamma i r r a d i a t i o n pneumococcus deoxy-r i b o n u c l e i c a c i d . R a d i a t i o n R esearch 3 * 116-120. El-.3adawi, A.A., A n g l e m i e r , A.F., and C a i n , R.F. 1964. E f f e c t s of s o a k i n g beef i n water, thermal-enzyme-i n a c t i v a t i o n and/or i r r a d i a t i o n on some of t h e muscle c h a r a c t e r i s t i c s i n v o l v e d i n meat t e x t u r e . Food T e c h n o l . 18 : 1807.-1810. G o l d b l i t h , S.A. 1970. SANE p e r s p e c t i v e s r e g a r d i n g r a d i a t i o n e f f e c t s . Food T e c h n o l . 24 : 250-256. G r e e n s t e i n , J . , and W i n i t z , M. I96I. C h e m i s t r y of t h e amino acid.. V o l . I . p. 684. Hamm, R. i960. B i o c h e m i s t r y of meat h y d r a t i o n . Advances i n Food Research 10 : 355-440. Hannan, R.3., and Shephered, H.J. 1959. Treatment of meats w i t h i o n i z i n g r a d i a t i o n . I . Changes i n odour, f l a v o u r and appearance o f c h i c k e n meat. J . S c i . Food A g r i c . 10 : 286 - 2 9 5 . Hansen, L . J . ,1960. E m u l s i o n f o r m a t i o n i n f i n e l y comminuted sausage. Food T e c h n o l . l4 t 56^-^,69. H e g a r t y , G.R., B r a t z l e r , L . J . , and P e a r s o n , A.K. 1963' S t u d i e s on t h e e m u l s i f y i n g p r o p e r t i e s of some i n t r a c e l l u l a r beef muscle p r o t e i n s . J . Food. S c i . 28 : 663-668. Kelmen, R.L., and. S a f f l e , R.L. I 9 6 3 . E f f e c t o f chopping t e m p e r a t u r e on t h e s t a b i l i t y of sausage e m u l s i o n s . Food T e c h n o l . 17 : 115-11?• Henderson, S.I7!., and P e r r y , R.L. 1966. I n t h e book " A g r i c u l t u r a l p r o c e s s e n g i n e e r i n g ", p.23. Hudspeth, J.P., and May, K.N. 196?. A s t u d y o f t h e e m u l s i f y i n g c a p a c i t y of s a l t s o l u b l e o r o t e i n s of p o u l t r y meat. Food T e c h n o l . 21 : I l 4 l - l l 4 2 . Ingram, V , M . 1 9 6 5 ' The b i o s y n t h e s i s of macromolecules. VI.A. Benjamin, I n c . , New York Amsterdam. 55 I s e , C M . , and Fox, S.W. 1955* The e f f e c t o f i o n i z i n g r a d i a t i o n upon p r o t e i n s . I n : U.S. Army Q u a r t e r m a s t e r Corp's R a d i a t i o n S t e r i l i z a t i o n . C h i c a g o , I l l i n o i s , pp.1 -16. Kominz, D.R. , Hough, A., Symonds, F. , and L a k i , K. 195^. The a m i n o - a c i d c o m p o s i t i o n of a c t i n , myosin, t r o n o m y o s i n and. t h e rneromyosins. A r c h . Biochem. B i o p h y s . 5° : 1 4 8 - 1 5 9 . K u z i n , A.M. 1964. R a d i a t i o n b i o c h e m i s t r y . ( T r a n s l a t e d by I . H a l p e r i n . E d i t e d by M.R. Q u a s t e l ) J e r u s a l e m , I s r a e l Program f o r S c i e n t i f i c T r a n s l a t i o n s . L a w r i e , R.A., Sharp, J.G., B e n d a l l , J.R., and Col e b y , B. 1 9 o l . Treatment of meats w i t h i o n i z i n g -r a d i a t i o n . V I I I . p l i , w a t e r - b i n d i n g c a p a c i t y and p r o t e o l y s i s o f i r r a d i a t e d raw beef and pork d u r i n g s t o r a g e , and ATP-ase a c t i v i t y o f i r r a d i a t e d r a b b i t muscle. J . S c i . Food. A g r i c . 12 s 742 - 7 5 1 . L a w r i e , R.A. I966. I n t h e book " Meat S c i e n c e ", p.254. P e r gam. on - p r e s s I n c . , Mew York. Lee, W.A. , and. Peacocke, A.R. 1951* The e l e c t r o m e t r i c t i t r a t i o n o f t h e sodium s a l t s of d e s o x y r l b o -n u c l e i c a c i d s . P a r t I I . The e f f e c t o f u l t r a s o n i c i r r a d i a t i o n . J . chem. S o c , pp. 337^-3378. Lowe, B. 1 9 5 5 ' E x p e r i m e n t a l c o o k i n g . 4 t h Ed. John W i l e y and. sons, New York. Lowey, S., and Cohen, C I962. S t u d i e s on t h e s t r u c t u r e o f myosin. J . mole. b i o l . 4 j 293-308. Lowey, 3., G o l d s t e i n , L., and. Luck, S. I966. I s o l a t i o n and c h a r a c t e r i z a t i o n of h e l i c a l s u b - u n i t from heavy raeromyosin. Biochem.. Z. 3 '^5 (1) • 248-254. McA r d l e , F . J . , and. D e s r o s i e r , N.W. 19.55• I n f l u e n c e o f i o n i z i n g r a d i a t i o n s on t h e . p r o t e i n components of s e l e c t e d f o o d s . Food T e c h n o l . 9 : 5 2 7 - 5 3 2 . Meyer, J.A., Brown, W.L., G i l t n e r , N.E., and Guinn, J.R. 1964. E f f e c t of e m u l s i f i e r s on t h e s t a b i l i t y of sausage e m u l s i o n s . Food. T e c h n o l . 18 : I 7 9 6 - I 7 9 O . Morgan, B..H. 1958. R a d i a t i o n C h e m i s t r y of Food. U.N. G e n e r a l Assembly. P r o c e e d i n g s of Second United. N a t i o n s ' I n t e r n a t i o n a l C o n f e r e n c e s on t h e P e a c e f u l Uses o f Atomic Energy. V o l . 2 7 , 4 2 3 - 4 2 7 . (A/CONF. 15/1 . V o l . 2?) 56 Meurath, H., and B a i l e y , K. 195^. The p r o t e i n s . V o l . I . New York Academic P r e s s . Osipow, I.L. S u r f a c e c h e m i s t r y - Theory and i n d u s -t r i a l a p p l i c a t i o n . R e i n h o l d P u b l i s h i n g Corp., New York. O s t l e , B. 1 9 5 ° ' S t a t i s t i c s i n r e s e a r c h . The Iowa S t a t e C o l l e g e P r e s s . AMWA, Iowa. P a r k e s , M.R. I967. R e t e n t i o n o f e m u l s i f y i n g c a p a c i t y of s a l t - s o l u b l e p r o t e i n d u r i n g f r e e z i n g , f r e e z e -d r y i n g and o t h e r p r e s e r v a t i o n t e c h n i q u e s . M.S. T h e s i s . U n i v . of G e o r g i a L i b r a r y , A t h e n s , G e o r g i a . Peacocke, A.R. , and. P r e s t o n , B.N. 1958. The d e g r a d a t i o n and d e n a t u r a t i o n of sodium, d e o x y r i b o n u c l e a t e by gamma-rays. J. Polymer S c i . 31 •' 1-14. P r o c t o r , B.E., and B h a t i a , D.S. 19.52. E f f e c t s of h i g h -v o l t a g e cathode r a y s on aqueous s o l u t i o n s o f t r y p t o p h a n e , t y r o s i n e , p h e n y l a l a n i n e and c y s t i n e . Biochem. J . 51 s 5 3 5 - 5 3 3 . • Rhodes, D.N,, and S o u t h e r n , E.M. 1967. I r r a d i a t i o n of meat p r o t e i n . AD 827999 European Research O f f i c e , U n i t e d S t a t e s Army. R i c e , R. V. , Brady, A.C, Depue, R. I T . , and K e l l y , R.E. 1966. Morphology o f i n d i v i d u a l macromole'cules and t h e i r o r d e r e d a g g r e g a t e s by e l e c t r o n m i c r o s c o p y . Biochem. Z. 3^5 (1) : 3 7 0 - 3 9 4 . S a f f l e , R.L., and G a l b r e a t h , J.W. .1964. Q u a n t i t a t i v e d e t e r m i n a t i o n of s a l t - s o l u b l e p r o t e i n i n v a r i o u s t y p e s of meat. Food Technol."18 : 1 1 9 - 1 2 0 . S a f f l e , R.L. I 9 6 8 . Meat e m u l s i o n s . Advances i n Food Research 13 : 1 0 5 - 1 6 0 . S t e n s t r o m , W. , and. Lohmann, A. 1928. E f f e c t s of ro e n t g e n r a d i a t i o n on s o l u t i o n s o f t y r o s i n e and c y s t i n e . J . B i o l . chem. 79 s 6 7 3 - 6 7 8 . St ens t rem, Vi., and. Lohmann, A. 1931 . E f f e c t s o f ro e n t g e n r a d i a t i o n on s o l u t i o n s of t y r o s i n e , phenol and. t r y p t o p h a n e . R a d i o l o g y ' 1 7 s 4 3 2 - 4 3 4 . S t r u c h k o v , V.A. ,' Dzhoun-khe, and S t r a z h e v s k a y a , N.B. I963. On t h e r o l e of DNA s u p e r m o l e c u l a r s t r u c t u r e i n c e l l r a d i a t i o n i n j u r y . U.S. Atomic Energy Comm. Res. Develop. Rept. A E C - t r - 5 4 2 8 , 1 0 - 2 0 . " i l l u s . 1Q62. From B a d i o b i o l o g i a 2 (1) : 1962. 57 S w i f t , G.E., L o c k e t t , C , and F r y a r , A . J . I 9 6 I . Comminuted meat emulsions - The c a p a c i t y o f meats f o r e m u l s i f y i n g f a t . Food T e c h n o l . 15 •• 468-473. S w i f t , C.S., and S u l z b a c h e r , W.L. 1 9 6 3 ' Comminuted meat emuls i o n s s F a c t o r s a f f e c t i n g meat p r o t e i n s as e m u l s i o n s t a b i l i z e r s . Food T e c h n o l . 17 : 224 - 2 2 6 . S w i f t , C.E. 1965* The e m u l s i f y i n g p r o t e r t i e s o f meat p r o t e i n . I n " P r o c . Meat In d . Reaserch Conference " pp. ?8-93« Am. Meat S c i . A s s o c . and Am. Meat I n s t . F o u n d a t i o n , C h i c a g o , I l l i n o i s . Tape, N.W. I 9 6 8 . I s i r r a d i a t i o n dead ? Food I n d u s t r i e s . December, pp. 3 0 - 3 2 . Trautman, J.C. 1964. F a t - e m u l s i f y i n g p r o p e r t i e s of p r s r i g o r and p o s t r i g o r oork p r o t e i n s . Food T e c h n o l . 18 : IO65-IO66. T u r n e r , E.W., and Olson, F.C. 1959. M a n u f a c t u r e of sausage and ground meat p r o d u c t s . U n i t e d S t a t e s P a t e n t 2 8 7 4 0 6 0 . Van den Tempel, M. 1 9 6 3 . E f f e c t o f d r o p l e t f l o c c u l a t i o n on e m u l s i o n v i s c o s i t y . I n " Symposium of Rheology of E m u l s i o n ". The M a c M i l l a n Co., Kev; York 7&n Wazer, J.R., Lyons, J.W., Kim, K.Y., and C d w e l l , R.E. 1963'. V i s c o s i t y and flow.measurement. I n b e r s c i e n c e P u b l i s h e r s , New York. W e b e r , G. , and L a u r e n c e , B.J.R. 195**• F l u o r e s c e n t i n d i c a t o r s of a d s o r p t i o n i n aqueous s o l u t i o n and. on t h e s o l i d phase. Biochem. J . 56 (4) p. x x x i . Zend.er, R. , L a t a s t e - D o r o l l e , C . , C o l l e t . , R.A., R o w i n s k i , P. , Radouco-Thomas , C . , B u s s e t , 3 . , and M o u t i n , R.F. 1958. S u r f a c e i r r a d i a t i o n and. a s e p t i c muscle a u t o l y s i s . U.N. G e n e r a l Assembly. P r o c e e d i n g s of Second U n i t e d N a t i o n s I n t e r n a t i o n a l Conferences on t h e P e a c e f u l Uses of A t o L i i c Energy. V o l . 27 : 3 8 4 - 4 0 0 . (A./C0MF. 1 5 / I , V o l . 27) 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0093360/manifest

Comment

Related Items