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Studies on the rehydration of irradiated freeze-dried beef Ni, Yeng-Wei 1969

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STUDIES ON THE REHYDRATION OF IRRADIATED FREEZE-DRIED BEEF by YENG-WEI NI B.Sc, Chung-Hsing University, 1967 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 August, 1969. In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h C o lumbia, I agree t h a t t h e 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 r e f e r e n c e and s t u d y . I f u r t h e r agree t h a p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g 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 g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada A B S T R A C T The t o t a l water uptake, rate of water uptake, extract release volume and maximum shear force were measured on a series of samples of i r r a d i a t e d freeze-dried beef. Forty seven pieces of round steak (2.5 cm x 2.5 cm x 10.4 cm or 1" x 1" x 4") were i r r a d i a t e d at one, three and f i v e mega-rad. The control samples were not i r r a d i a t e d . Half of the samples were i r r a d i a t e d when fresh, and the other half were i r r a d i a t e d a f t e r freeze drying. This procedure has been defined as the "fresh-dry" i r r a d i a t i o n sequence throughout the report. The samples were frozen i n an a i r blast at two temperatures (-22.2°C and -56.1°C). Freeze-drying was carr i e d out below 300 microns of Hg and a maximum shelf temperature of 15.6°C (60°F). There appears to be three phases of water uptake: 1) A very rapid, almost instantaneous, absorption. 2) A more gradual uptake (called Part.1 i n the report). 3) A r e l a t i v e l y slow asymptotic approach to an equilibrium condition (Part 2). These two l a s t phases are shown to be straight l i n e s when the logarithm of the water uptake i s plotted against the logarithm of the immersion time. I r r a d i a t i o n l e v e l has no s i g n i f i c a n t e f f e c t on the f i n a l water content or on the slow asymptotic absorption (Part 2) or the extract release volume, but has a s i g n i f i c a n t e f f e c t on the gradual water uptake (Part 1) and on the shear press force. Fresh-dry irradiation sequence (and freezing rate) have a significant effect on the total water uptake and on the slow asymptotic water (Part 2) uptake, but not on the gradual water uptake (Part 1), or on the extract release volume or on the shear press forces. Freezing rates have a significant effect on the total water uptake, but not on the slow asymptotic water uptake (Part 2), on the gradual water uptake (Part 1), on the extract release volume or on the shear press forces. The highest total water uptake was found for the meat irradiated when fresh, and slow frozen at -2 2.2°C. The mechanism of the gradual absorption appears to follow a phenomena of water flow, as evidenced by the straight line relationship found in the plots of logarithm water uptake versus logarthm immersion time. TABLE OF CONTENTS Page Introduction 1 Review of Literature • 2 Experimental methods 13 (1) Preparation of Samples 13 (a) Procurement of samples 13 (b) Size of sample 13 (2.) Freezing and freeze-drying 13 (3) Irradiation 15 (4) Rehydration 16 (5) Extract release volume 16 (6) Shear press measurements 17 (7) Analytical methods 17 Results 18 Moisture content 18 Rehydration 18 Extract release volume 20 Shear press 20 Discussion of Results Moisture content 20 Rehydration 21' Total water uptake 21 Rehydration rate analysis 24 Page Extract-release volume 29 Shear press 32 Conclusions 35 List of References 37 Appendix A 42 Appendix B 46 Appendix C . 6 1 LIST OF TABLES Table Page 1 Experimental design 14 2 Moisture Content of fresh beef 18 3 Very rapid i n i t i a l water uptake (% D.B.) for irradiated freeze dried beef 19 4 Analysis of variance of the final water uptake of freeze-dried beef: Effect of fresh-dry irradiation sequences, irradiation levels, and freezing rate 22 5 Mean total water uptake (% D.B.) of freeze-dried beef irradiated fresh and irradiated after freeze-dried 23 6 Mean total water uptake (% D.B.) of freeze-dried beef frozen at different temperatures 23 7 Analysis of variance of the slopes of the regression lines of log (moisture) vs. Log (time) as shown in Appendix B 27 8 Comparison of the slope of the regression lines for part 1 of the rehydration process as influenced by irradiation levels 28 9 Comparison of the slope of the regression lines (part 2) as influenced by fresh-dry irradiation sequence 28 10 Analysis of variance of extract-release volume of reconstituted freeze-dried beef: Effect of irradiation levels, fresh-dry irradiation sequence, and freezing rate 30 11 Mean extract-release volume (average of 6 samples) as influenced by irradiation level and fresh-dry sequence 31 12 Analysis of variance of Kramer Shear press force for rehydrated freeze-dried beef: Effect of irradiation levels, fresh-dry irradiation sequence and freezing rate 33 Page Mean Kramer shear force values for rehydrated freeze-dried beef irradiated at four dose levels 33 Mean Kramer shear press force values for rehydrated freeze-dried beef subjected to two fresh-dry irradiation sequences and freezing rates 34 Water loss during freeze-drying and final water content of the freeze-dried beef for animal no. 6868 (group A) 43 Water loss during freeze-drying and final water content of the freeze-dried beef for animal no. 6852 (group B) 44 Water loss during freeze-drying and final water content of the freeze-dried beef , for animal no. 6852 (group C) ~ 45 Analysis of part 1 regression lines for rehydration of freeze-dried beef 59 Analysis of part 2 regression lines for rehydra-tion of freeze-dried beef 60 Extract-release volume of the rehydrated beef samples 62 Shear press value of the rehydrated beef samples 63 LIST OF FIGURES FIGURE PAGE 1 Recorder used in the rehydration process showing weight gains (abscissa) with time (ordinate). 16a 2 Equipment used for the rehydration process. 16a 3 Model of c a p i l l a r y flow. 24 4 Rehydration model. 25 5 Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 1, 2, 3 and 4 represents sample IA, 2A, 3A and 4A respectively. 47 6 Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 5, 6, 7 and 8 represents sample 5A, 6A, 7A and 8A respectively. 48 7 Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 9, 10, 11 and 12 represents sample 9A, 10A,'11A and 12A respectively. 49 8 Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 13, 14, 15 and 16 represents sample 13A, 14A, 15A and 16A respectively. 50 9 Logarithm of water uptake versus logarithm time f o r i r r a d i a t e d freeze-dried beef: Set 17, 18, 19 and 20 represents sample IB, 2B, 3B and 4B respectively. 51 10 Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 21, 22, 23 and 24 represents sample 5B, 6B, 7B and 8B respectively. 52 11 Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 25, 26, 27 and 28 represents sample 9B, 10B, 11B and 12B respectively. 53 FIGURE PAGE 12 Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 29, 30, 31 and 32 represents sample 13B, 14B, 15B and 16B respectively. 54 13 Logarithm of water uptake versus logarithm time f o r i r r a d i a t e d freeze-dried beef: Set 33, 34, 35 and 36 represents sample 2C, 3C, 4C and 9C respectively. 55 14 Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 37, 38, 39 and 40 represents sample 10C, 11C, 12C and 5C respectively. 56 15 Logarithm of water uptake versus logarithm time f o r i r r a d i a t e d freeze-dried beef: Set 41, 42, 43, and 44 represents sample 6C, 7C, 8C and 13C respectively. 57 16 Logarithm of water uptake versus logarithm time f o r i r r a d i a t e d freeze-dried beef: Set 45, 46 and 47 represents sample 14C, 15C and 16C respectively. 58 ACMOWLFJJGMENTS The writer wishes to express his appreciation for assistance in this study by: Professor E. L. Watson, Department of Agricultural Mechanics and Agricultural Engineering, who directed this research, provided encouragement, advice and guidance with patience. Dr. J. F. Richards, Department of Food Science, for counsel on the research project, and for arranging for the provision of beef samples and laboratory facilities. Mr. M. A. Tung, for suggestions and assistance in the use of the I.B.M. 360 computer and provision of computer programmes. Mr. W. Gleave and Mr. E. Nyborg, for suggestions and assistance in the construction of the strain gauge transducers. 0 INTRODUCTION Rehydration of freeze-dried beef has been studied for some time (1,20), but the process has had limited application in practical fields. The reason has been that the properties of beef rehydration are such that i t does not reconstitute to its original state. The problem remains that once the beef is frozen and freeze-dried, i t has lost its f u l l water holding capacity and rehydration to its original colour, tenderness and other constituents is difficult. It is generally accepted that rehydration behavior of dried products is important in .determining their organoleptic and nutritional value. Prolonged rehydration may cause a loss of water soluble constituents such as pigments, carbohydrates and amino acids. The extent of recons-titution is considered to affect the texture of rehydrated products. The purpose of this thesis is to study four different irradiation levels, "fresh/dry" irradiation sequences and two freezing rates to see how these various procedures affect the water uptake, rehydration rate, shear resistance and water holding capacity of irradiated freeze-dried beef. The results of such experiments would be helpful in advancing the understanding of the process of rehydration of meat and in improving the acceptability of freeze-dried meat. 2 REVIEW OF THE LITERATURE General Problems on Rehydration Auerback et al. (1) proposed that the ability to rehydrate rapidly is one of the most distinctive qualities of freeze-dried products and is a factor that demonstrates the superiority of freeze-drying over other methods of dehydration. In order to obtain a satis-factory product, Auerback et al. found the direction of muscle fiber and angle of cut to be quite important. Smithies (30) mentioned that unsatisfactory processing conditions or prolonged storage may affect the rehydration time, tenderness and juiciness of the products. Smithies also reported that the protein denaturation or migration of soluble solids or fat which takes place makes the structure less hydrophilic and increases the time required for the water to penetrate the porous structure; he found that relatively rapid freezing gives a product which rehydrates more slowly than does slow freezing. Auerback et al. (1) reported that the mechanism of rehydration of freeze-dried muscle involves two stages: fir s t l y , the penetration of water through the cavities in the tissues, (either the large ones formed between the fibers in slow freezing or the minute ones formed within the fibers in rapid freezing); secondly, the penetration of water through the muscle fibers of the tissue. The porosity of the muscle fibres is related to the rate at which the tissue is frozen and also to the storage temperature conditions. Auerback also stated that: 3 "In both the slowly and the rapidly frozen tissues, water would appear to penetrate more freely through the muscle fibers than through the cavities. With rehydration the time necessary for total or nearly total water intake and water holding capacity has to be considered. Quick rehydration is often combined with relatively low water holding capacity. This is caused on the one hand by the growth of large ice crystals during slow freezing which results in relatively large holes in the dry product through which water can permeate the dry product quickly. On the other hand during the slow freezing procedure the material may suffer relatively substantial structural and biochemical changes which result in decreased water holding capacity". (1) Properties of Beef Koshland and Herr (18). reported that muscle proteins are responsible for the binding of water in meat. The muscle proteins consist of water-soluble protein and non-water-soluble proteins. The water insoluble muscle protein represents the structural substance in meat. They found that the f i b r i l l a r proteins consist of myosin, which shows a specific interaction with water. Huxley and Hanson (13) re-ported that the f i b r i l l a r proteins also consist of actin, X-protein, and stroma proteins. Ham (9) thought that changes of the water holding capacity of meat may mainly concern actin and myosin"or the complex actomyosin. Fujimaki and Nakajima (8) believe that globular proteins also have some influence on water holding capacity, and i t appears that meats containing a greater quantity of globular protein have a greater water holding capacity. 4 Hamm (9) also found that the low-molecular weight water-soluble compounds contribute considerably to meat hydration. This effect may be caused mainly by inorganic ions because low molecular weight compounds can be substituted by NaCl solution, which has the same ionic strength as muscle juice.(9). • Olcott and Fraenkel-Conrat (26) found that the activity of proteins for binding water is diridnished by blocking polar groups with certain reagents, and proved in that manner that polar groups are responsible for the water binding. According to Pauling (27) the i n i t i a l phase of binding of water by protein consists of the binding of one « water molecule by one polar group. The affinity for water of the different polar groups varies. Therefore water attaches f i r s t to the most active groups and then to the less active. According to Nemethy and Scherage (24) the characteristic configuration and reactivity of proteins are governed to a large extent by covalent disulfide bonds and by noncovalent interactions between side chains. Hydrophobic bonds, or the tendency for nonpolar groups to 0 associate in an aquepus environment are thought to be of considerable importance in stabilizing protein structure. This view can be readily justified by considering the anrino acid composition of typical proteins. In general, the amino acids with nonpolar side chains constitute 35-50% of the total amino acids in proteins (24,25). Since the nonpolar side chains have a low affinity for water, they tend to approach one another until they are within their Van der Waals radii and thereby irrinimize their contact with water. 5 The structure of the water molecule enables i t to form weak but directed bonds with other water molecules and with certain groupings on the principal macromolecules present, in foodstuffs. The hydrogen atom has a special function, stemming from the absence of inner shells of electrons in the formation of this type of secondary bond, which justifies the use of the term 'hydrogen bond' for a l l interactions of a similar character. In most foodstuffs hydrogen bonding exists between water molecules, between water and small and large molecules and ions and as a cross link between ions of macromolecular components. Water appears to be bound in several ways in most biological materials. Use of the term "bound water" often leads to a great deal of confusion since no one definition has been universally accepted. As the water present is always "bound" in some way to one or other of its components, this is a complex matter and depends on many different factors. Kuprianoff 0.5,.) pointed out two difficulties in the de-finition of "bound water" - the water will be bound to protein in a manner different from that to carbohydrates or acids, i t will be advisable to consider the problem of "bound water" with special reference to different foods or groups of foods of similar structure and composition, e.g. fish and meat. The second difficulty arises because the definition of "bound water" is based on the method used for its determination, and every individual method has its own efficiency or capacity of expelling water. 6 Bull (.2) presents probably the two most common ways of defining bound water: 1) Bound water can be defined in terms of the water which remains unfrozen at some prescribed temperature below 0°C. The temperature usually chosen is -20°C, although Luyet (19) defines bound water as "water which does not crystallize at any temperature". 2) Bound water can be defined in terms of the amount of water in the system which is unavailable as a solvent. A general definition of bound water has been given by Kupriaroff (15) as "that part of the water content of a product which remains in i t in an unchanged (or bound) state after application of the usual drying procedures, such as freezing, chemical'dehydration, etc., and which can be expelled only by heating to 100°C-110°C for a sufficiently long time". Irradiation Ionizing radiation can destroy spoilage microorganisms regard-less of the state of the meat, that i s , whether raw or cooked, frozen or unfrozen. Some effects other than the destruction of spoilage microorganisms do occur. These include: 1) Color changes - the red pigments of raw meats and poultry become brownish. Cooked meats and poultry in the absence of oxygen turn pink. The magnitude of the color changes is somewhat dependent on the dose (32): 2) Texture - a softening of the lean tissue can occur, the degree of this effect being related to the dose (3) • 3) an odour and/or flavour change may occur. This 7 most important organeleptic change, generally regarded as undesirable, is characteristic and resembles scorching. Within limits, the amount or irradiation-flavour development is dependent on the dose (32). Whitehair et al. (33) reported that within a species, i t appears that the flavour or odour sensitivity is not related to the fat content of the tissue. Because of the high percentage of water in meats and other foodstuffs the reactions that occur when water is irradiated are of primary importance. By radiolysis of water, H+, OH , t h ^ , and H^  are the final major products, but free radicals are formed along the path of the primary electron and react with each other as diffusion occurs. Also some of the products formed along the track move about and react with solute molecules. In order to examine how the meat is affected by irradiation, Weeks and Garrison (34-) studied the influence of irradiation on pure protein in solution. These authors proposed that the major products formed by the irradiation of glycine in solution are NH^ , CHOCOOH, Yi^, and C02. Doty (5) stated that other amino acids show similar reactions, although the influence of certain side groups will change the overall reaction products. Fujimaki et al . (7) also reported that aromatic amino acids, especially phenyl-alanine, tend to be sensitive to irradiation, and the ring structure will be altered. Free arginine, tyrosine, and methionine are also destroyed to a greater extent than other amino acids. 8 In the case of cysteine, Doty (5) proposed that the -SH group is so efficient in trapping free radicals that the rest of the molecule is almost completely protected from attack, and cystine is the major product formed. In addition, some H2S is formed and oxidation reactions may produce other products as well. Hedin et a l . (12) reported that there is a general decrease in the unchanged amino acids, with almost total loss of methionine and cysteine and 25 percent loss of histidine. Fox et al. (6) reported that other chemical changes occurring when meat is irradiated cause modifications in the myoglobin of red meats and some destruction of the vitamins present. When red meats are irradiated at dosages of 1.5 megarad, or higher, appreciable quantities of metmyoglobin are produced. In low acid food, such as uncured meats, the radiation dose required for sterilization is about 4-.5 megerad (35). For bacon i t is 2.0 or 2.5 megarad. For chicken, i t is about 3.5-4.0 megarad (28). Sparrman et al . (29) reported that minimum irradiation damage to Agrestic stolonifera seed occurred at 15% moisture content. Wedemeyer and Dollar (36) reported that the sulfhydryl release resulting from irradiation reaching a maximum at about 20% moisture content for sole f i l l e t s . There is very l i t t l e specific information on texture changes during irradiation of meats. But i t is generally agreed that, after irradiation, meats become softer and more tender. For example, Kirn et al.(16) noted that raw beef given 2 megarad retained a good texture even after 5 years at 7°C. Coleby et al. (4) noted considerable immediate softening accompanied by loss of fluid with both raw beef and 9 pork. Lawrie et al. (21) found on examination of the raw tissue no evidence of breakdown of connective tissue after 5 Megarad irradiation. Bailey et al. (3) reported that the treatment of pork or beef with ionizing radiation resulted in a tenderization, as judged by a taste panel after cooking, detectable at a dose of 2 megarad and marked at 4-megarad. Freezing Process In principle the rate of freezing may be conveniently expressed as the time spent between i n i t i a l ice crystal formation and complete solidification. Two principal freezing rates were considered by Luyet (19): one in which the material stays at the freezing temperature about one hour; the other in which i t stays there about 10 min. The two corresponding modes of freezing will be designated, hereafter, respec-tively, as slow and rapid freezing. The outstanding characteristics of freeze-dried material which had been frozen slowly is its relatively course, spongy structure. Freeze dried tissues which had been frozen rapidly have a fine porous structure. Kuprianoff (17) found when the temperature is decreased below the freezing point of a food, the crystallization of ice within the water phase begins when nucleation occurs. Having in mind that most biological tissues supercool, the nucleation process will start at a lower temperature than the freezing point, depending on the type of solution and its inclination for supercooling. In reality specific freezing point of food does not exist; what we call "freezing point" is the equilibrium temperature at the beginning of ice formation; in the weak unsaturated solution pure ice is formed, which is in 10 equilibrium with the remaining more concentrated solution; the freezing point of the remaining solution has been depressed because of its increased concentration. At some particular concentration the remaining solution will freeze as a whole, forming mixed crystals of solute and solvent at its eutectic point. In biological tissues with given structure the water phase is. contained in single and complex systems (cells) separated from each other by cel l wall and membranes; in an intact tissue these cell walls and membranes - being semipermeable - are able not only to maintain different concentrations of the same substances in the solutions in neighbour cells, but also to hinder the crystallization of water (slowing down the rate of heat transfer) slowing down the rate of ice formation and influencing the speed of growth of the ice crystals. Under practical conditions of temperature drop during the freezing of foods crystalliza-tion usually starts in the intracellular connective tissues and proceeds with some delay in the interior of the cells (15) An important consequence for food freezing is the increase in water volume during ice formation, which amounts to about 10% when ice is formed at 0°C. Therefore, the cell structure of most foods will be exposed to mechanical forces during the freezing process. Kuprianoff (15) proposed that although the tissues of foodstuffs are exposed to a considerable strain by the expansion of water during freezing, in most cases the foodstuff will have sufficient elasticity to ininimize disruption, i f the product, is frozen rapidly. The muscles of a l l warmblooded and of some coldblooded animals have especially good 11 resistance against deformation. Their elasticity and ^constitution ability are remarkably good, when tested immediately after freezing and subsequent thawing. If larger crystals are formed - by slow freezing -or i f the strength of the cell structure is low, then the fine structure of tissue may be disrupted and will partially collapse; this kind of freezing injury leads to the loss in natural strength of tissues, to permeability of ce l l walls, to partial loss of water holding capacity and to impairment of the food texture. After thawing of the product the permeability of the tissue results in a drip and in loss of texture, giving a soft product. This leads to a decrease in organoleptic^ ' acceptability due to lack of juiciness and increase in toughness. Freeze-drying process The process of freeze-drying is based on the principle that the water of an aqueous system can be separated from a nonvolatile component by freezing and removal of the ice by sublimation, leaving a dry substrate. Meryman et al. (23) proposed that the process of freeze-drying of a frozen speciman can be divided into three steps: 1) the introduction of heat to supply the energy necessary for sublimation, 2) the transfer of water vapor from the subliming ice crystal through the already dried shell of the speciman, and 3) the removal of water vapor that reaches the specimen surface. Harper and Tappel (10) pointed out that sub-limation always takes place from the ice surface. As sublimation progresses the ice phase recedes and becomes surrounded by a dried layer. The heat for sublimation must be transferred through this dried layer, and water 12 vapor must flow out through the same layer. Throughout most of the drying process, this dried layer resists both the inward transfer of heat and the outward transfer of water vapor. Harper et al. (11) found that the drying process involves a balance between the outward flow of vapor (mass transfer) and the inward flow of heat (heat transfer). Vapor movement from the ice phase takes place by hyobxdynamic flow as a result of a gradient in water vapor pressure. It should be noted that the partial pressure of water vapor can never rise above the equilibrium vapor pressure of the ice in the frozen material. EXPERIMENTAL METHODS 13 (1) Preparation of samples (a) Procurement of samples A l l the samples for the experiment were obtained from the Agricultural Research Station, Agassiz, B.C. The samples were as follows: Beef Animal No. 6868 5th Round Beef Animal No. 6852 4th Round Beef Animal No. 6852 5th Round Beef Animal No. 6852 6th Round (b) Size of sample The fresh meat samples were cut into even sizes of 2.5 cm x 2.5 cm x 10.2 cm (1" x 1" x 4"), each weighing approximately 75 grams, and were subjected to freezing and then freeze-drying. After the freeze-drying, the samples were trimmed to 1.9 cm x 1.9 cm x,7.6 cm (3/4" x 3/4" x 3") sizes, each weighing approximately 8.50 grams. The experiment is a factorial experiment, with three independent variables: Irradiation levels, (4 levels) "fresh/dry" irradiation (2 sequences), and freezing rate (2 rates) which are 4 x 2 x 2 = 16 factors. The experimental design is shown in Table 1. (2) Freezing and Freeze-drying The freezing operation was carried out at two different tempera-tures, -22.2 °C (-8°F) and -56.1 °C (-69°F). Two pairs Cu-Constantan thermocouples were used to indicate the temperatures' at the surface and the center of the sample and to detect the end points when the temperature TABLE 1 EXPERTJ1EOTAL DESIGN Irradiation Levels 0 Mrad 1 Mrad 3 Mrad 5 Mrad Freezing temperature I -22.2'2°C (-8°F) Irradiated while fresh 1A* IB IC 2A 2B 2C 3A 3B 3C MA MB MC Freezing temperature I -22.2'2°C (-8°F) Irradiated while dry 9A 9B 9C 10A 10B IOC 11A 11B 11C 12A 12B 12C M H OJ CD & t o (0 •P M O •S ° H N iH CU QJ ID £ •? Irradiated while fresh 5A 5B 5C 6A 6B 6C 7A 7B 7C 8A 8B 8C T3 •H X) CU S H £ 'H £ • § 13A 13B 13C IMA 1MB IMC 15A 15B 15C 16A 16B 16C sample identification symbol A Animal No. 6868 B and C Animal No. 6852 15 at the centre equals the surface temperature. Temperatures were recorded by a Moseley recorder. It took 10.25 minutes for the temperature at the centre of the sample to pass through 0°F when frozen at -56.1 °C (-69°F) and 125 minutes when frozen at -22.2. °C (-8°F). In order to prevent water loss from the samples during theofreezing process, the samples were kept in plastic bags. Al l the samples were freeze-dried in a Thermovac Model FDC-10-DR freeze-dryer. In this freeze-dryer, heat was supplied by an electric heating system inside the shelves, maintained at 15.6°C (60°F) and the absolute pressure was maintained at values less than 300 microns of Hg by a positive displacement vacuum pump and a condenser at -56.1°C (-60°F). (3) Irradiation A Gamma Cell 220 Irradiator with a Cobalt-60 source was used in this study. The dose rate was 1.1 Mrad per hour. The irradiation was carried out on both fresh and freeze-dried meat samples. Three g different irradiation dosages, 1, 3 and 5 megarads (1 Megarad = 10 Rad , 1 Rad = 100 ergs/giJ for the experiment were used. In order to prevent damage to the sample due to heat during the irradiation operation, a l l the samples were kept at an ambient temperature of 0°C by surrounding the samples with ice cubes. One half of the fresh meat samples were fi r s t subjected to irradiation and then were frozen at -22.2 °C (-8°F) or -56.1 °C (-69°F), and freeze-dried. The other half of the samples were fi r s t freeze-dried and then irradiated. This procedure is designated as "fresh/dry" irradiation sequence throughout this report. 16 (4) Rehydration The samples were rehydrated by immersing in a water bath at room temperature (22°C) and atmospheric pressure. The sample was kept completely immersed in water at room temperature with its muscle tissue perpendicular to the surface of water, until a straight line was recorded on the recorder chart indicating no more gain in weight (Figure 1). The gain in weight due to absorption of water in the sample was measured by a cantilever type strain gauge transducer. The sample was attached to one end of the cantilever beam. The gain in weight was recorded by a Moseley recorder connected to the strain gauge transducer (Figure 2). The cantilever beam strain gauge transducer was calibrated by applying a series at known loads and recording the resulting bridge .output. The transducer was found to have linear output characteristics. Hence, no calibration curve is presented. Strain gauges were mounted so that the transducer was temperature compensated. (5) Extract release volume The method used by Jay (14) was followed to measure the Extract Release Volume (ERV). ERV was determined by weighing 25 grams of rehydrated meat and homogenizing for 2 minutes with 100 ml of distilled water added just prior to blending. The homogenates were poured directly into the funnels, equipped with a sheet of filter paper. The extract was collected in 100 ml graduated cylinders. The collection was timed for 15 minutes from the point of adding the homogenates to the funnel. The 15-minute volumes were averaged and treated as the Extract Release Volume. FIGURE 1. RECORDER USED IN REHYDRATION PROCESS, SHOWING WEIGHT GAIN (ABSCISSA) WITH TIME (ORDINATE). FIGURE 2 . EQUIPMENT USED FOR THE REHYDRATION PROCESS. 17 (6) Shear Press measurements The shear press results were obtained with an Allo-.lramer Shear Press, Model TP-2 Texture-press and TR-1 Texturecorder. A l l the samples (1.9 cm or 3/4" thick) were placed in a single blade Kramer cell for each test. A downstroke of 30 seconds and a 2500 lb ring were used. Results were recorded as pounds force as measured at the peak of the shear value. (7) Analytical Methods The experiment was treated as a factorial experiment, the methods of analysis of variance, F-ratio tests, and simple linear re-gression were used as stated by LeClerg et al . (22) and by Steele and Torrie (31). RESULTS Moisture Content TABLE 2 MOISTURE CONTENT OF FRESH BEEF Animal No. 6868 Animal No. 6852 Moisture Content Moisture Content Dry Basis % Wet Basis % Dry Basis % Wet Basis % 1 305.26 75.32 1 306.28 75.39 2 297.22 74.83 2 288.92 74.29 3 310.60 75.65 3 315.21 75.92 4 293.22 74.57 4 298.53 74.91 5 303.26 75.20 5 299.47 74.97 6 296.32 74.77 6 307.13 ' 75.44 7 274.83 73.32 7 284.78 74.01 8 283.67 73.94 8 297.99 74.87 Mean 292.17 74.70 Mean 299.74 74.98 The moisture content of the fresh beef is shown in Table 2. The weights of the fresh samples of the freeze-dried samples, and the water losses during freeze-drying as percent dry basis (% D.B.), and the moisture content of the freeze-dried samples as percent wet basis, % W.B. and % D.B. are presented in Appendix A. Rehydration The very rapid i n i t i a l water uptake is reported in Table 3. The rest of the rehydration data are shown graphically in Appendix B. 19 TABLE 3 VERY RAPID INITIAL WATER UPTAKE (% D.B.) FOR IRRADIATED FREEZE DRIED BEEF Sample No. Water uptake Dry matter wt. Sample No. Water uptake x 0^0 Dry matter wt. Sample No. Water uptake D.M. wt. x IA 182.57 IB 119.13 IC -2A 126.14 2B 87.58 2C 114.92 3A 71.19 3B 107.49 3C 58.39 4A 53.05 4B 70.36 4C 57.45 5A 110.21 5B 131.62 5C 145.37 6A .118.46 6B 74.04 6C 110.28 7A 33.88 7B 62.06 7C .146.81 8A 41.44 8B 84.97 8C 116.30 9A 51.52 9B 117.49 9C 137.96 10A 7.40 10B 23.14 • * 10C 85.57 1LA 31.07 11B 55.21. 11C 90.74 12A 35.14 12B 39.94 12C 109.95 13A 19.15 13B 131.65 13C 161.77 14A 3.80 14B 36.06 14C 108.42 15A 51.43 15B 36.31 15C 122.77 16A 17.90 16B 28.83 16C 111.04 100 20 The analysis of variance of the total final water uptake is given in Table 4. Table 5 and Table 6 show the mean final water uptake (% D.B.) as influenced by "fresh-dry" irradiation sequence and freezing rate respectively. The rates of rehydration are shown in Appendix B as a series of graphs showing the logarithm of water uptake versus the logarithm of immersion time. The regression analysis of the logarithm of water uptake versus logarithm time is given in Appendix B. The analysis of variance of the slope of the regression lines is presented in Table 7. Extract-Release Volume The Extract-Release Volume (ERV) results are shown in Appendix C. The analysis of variance of of ERV is given in Table 10 and Table 11. Shear Press The Kramer shear force data are shown inAppendix C. The analysis of variance of shear press data of the rehydrated freeze-dried beef is given in Table 12. A comparison of mean values of shear force found for the rehydrated beef treated with four levels of irradiation is presented in Table 13. The combined effect of freezing rate and "fresh-dry" irradiation sequence on mean shear press values are shown in Table 14. DISCUSSION OF RESULTS Moisture Content The moisture content of the fresh beef samples appeared to be normal (Table 2). The water losses during freeze-drying were somewhat variable (Appendix A). The water loss during freeze-drying of certain samples (i.e. Group A, No, 2,3; Group B, No. 7), does not f a l l within 21 the range of moisture contents found for fresh beef. Presumably these samples must have had i n i t i a l moisture contents outside the range which was. found for fresh beef. The moisture contents of the freeze-dried samples (see Appendix A) were also quite variable. This may be due to different i n i t i a l moisture contents and/or different freeze-drying regimes. Rehydration There are two rehydration characteristics of freeze-dried products. Most workers have studied the total amount of water absorbed. In these studies the rate of water absorption was also measured. It was noted that some water was absorbed very rapidly (almost instantaneously) in a l l samples. However the amount of water absorbed varied greatly between samples (Table 3). Total water uptake It is shown in Table 4 that there was no significant difference for the different levels of irradiation on the final water uptake. However, according to Fujimaki et a l . (7) irradiation of meats produces some damage to the protein, but in this study protein damage to meat was not investigated and i t is therefore impossible to say whether or not the rehydration was mainly due to the absorption of water by protein. A highly significant difference in water uptake between the samples irradiated when fresh and when freeze-dried was found by the analysis of variance (Table 4). The samples which were irradiated in the fresh state were found to reabsorb more water (Table 5). The fact that the samples irradiated after freeze-drying regained less water than the samples irradiated in the fresh state would indicate that greater damage 22 TABLE 4 ANALYSIS OF VARIANCE OF THE FINAL WATER UPTAKE OF FREEZE-DRIED BEEF: EFFECT OF FRESH-DRY IRRADIATION SEQUENCES, IRRADIATION LEVELS, AND FREEZING RATE Source DF Sum Sq Mean Sq F Prob Irradiation levels (A) 3 3677.4 1225.8 1.68 0.1902 Fresh-dry irradiation sequence (B) 1 5812.2 5812.2 7.96** 0.0080 Freezing rate (C) 1 4904.0 4904.0 6.71* 0.0137 AB 3 2035.4 678.48 0.92 0.4399 AC 3 2485.8 828.61 1.13 0.3505 BC 1 611.4 611.40 0.84 0.3704 ABC 3 3631.7 1210.6 1.66 0.1947 Error . 32 . 23379.0 730.59 Total 47 46537.0 significant at 95% level significant at 99% level occurred under the extremely low moisture condition. However, this does not agree with Wedemeyer and Dollar (36) who reported that the least irradiation damage of fish occurred at low mristure content. This would indicate that their measure of irradiation damage (-SH production) does . not measure irradiation damage to rehydration. The analysis of variance (Table 4) shows that the freezing temperature has significant effect on the final amount of water absorbed. 23 The difference (Table 6) in the water holding capacity of the sample may be due to tissue structure as well as membrane permeability. This can be explained in two ways: (1) higher freezing temperature breaks the cell walls and produces larger cavities for water retention, (2) intact cell walls attained by lower freezing temperature prevent entrapped air from being expelled and the subsequent free passage of water. These results are in an agreement with the work of Smithies (30). TABLE 5 MEAN TOTAL WATER UPTAKE3, (% D.B.) OF FREEZE-DRIED BEEF IRRADIATED FRESH AND IRRADIATED AFTER FREEZE-DRYING Fresh Freeze-dried Water uptake 1 0 0 215.1117 193.1037 Dry matter wt a average of 24 samples TABLE 6 MEAN TOTAL WATER UPTAKE3' (% D.B.) OF FREEZE-DRIED BEEF FROZEN AT DIFFERENT TEMPERATURES -22°C -56°F Water "P*ake 1 0 0 214.2154 194.0000 Dry matter wt average of 24 samples 24 Rehydration rate analysis Rehydration might be compared to the flow of water through a capillary: FIGURE 3. MODEL OF CAPILLARY FLOW It is known that the fluid flow velocity is a function of the flow pressure difference and the length between two points. It is: Q - K ( A P ) N . . . . (1) X w h e r e Q = wt/unit time X = length of tube A P = p 1 - P 2 K = constant n = coefficient 25 If a rehydration model similar to Figure 4 is assumed water will flow through the material under a pressure difference of P Q - P ^ =4P If i t is assumed that the wetted interface advances as a "wetted front" into the dry material, then the pressure difference will be constant, but the thickness of the layer will increase. The amount of water (dw) flowing in time dt will be related to the increase in the thickness of the wetted layer dx.' Thus we can write dx «< dw and x at w. Also Q ^ dw dt Hence, equation (1) can be rewritten as: d w = (K*) (Ap) n w dt wndw = (K*) (Ap) n dt W* + 1 = (K1) (Ap n) (t) + C when n * 1 n + 1 (2) .'. log W oc. log t . . . (3) Therefore i t would appear that the rate of water uptake should vary logarithmatically with the logarithm of time. When the log water uptake (% D.B.) is plotted versus log-time, a straight line relationship is found (Appendix B). This indicates that there is a linear relationship 26 between log moisture and log time which agrees with equation (3) shown above. It was also found that the lines found for a large number of runs break into two parts (see graphs in Appendix B). This would indicate that the mechanism of rehydration proceeds in two stages which agree with the hypothesis of Auerback et a l . (1). The straight line rehydration line (see Appendix B) prior to the break in the curve is called part 1, while the line following the break is called part 2. There is also a very rapid i n i t i a l water uptake (Table 3). Upon inspection of log log plots (Appendix B) i t is obvious that there are considerable differences between replications. No reason has been found to explain these differences. There are several variables that were not measured in these experiments which might con-tribute to this variation: 1) variation in the moisture content of the freeze-dried meat 2) variation in fat content 3) different tissue structure and M-) unknown differences in freezing rate Further study will be required to determine whether or not any of the above factors contributed to this variation between replications. An analysis of variance of the slope of the regression lines (Table 7) shows that the irradiation levels have a significant effect on the slope of f i r s t part of the rehydration process (part 1 of the regression analysis, see Table Bl, Appendix B). Table 8 indicates that the control (unirradiated) samples rehydrated significantly slower than the irradiated samples. According to Duncan's New Multiple Range Test, there is no 27 TABLE 7 ANALYSIS OF VARIANCE OF THE SLOPES OF THE REGRESSION LINES OF LOG (MOISTURE) vs. LOG (TIME) AS SHOWN IN APPENDIX B Source d.f. S.S. M.S. F Irradiation levels 3 3 0.1961 0.0653 3.0801* Experimental error 44 0.9337 0.0212 Total 47 1.1298 Irradiation levels^ . 3 0.0955 0.0318 2.1913 Experimental error 44 0.6418 0.0145 Total 47 0.7373 • , Irradiation sequence3 1 0.0383 0.0383 1.6160 Experimental error 46 1.0915 0.0237 . Total 47 1.1298 Irradiation sequence^ 1 0.1202 0.1202 8.9701** Experimental error 46 0.6171 0.0246 Total 47 0.7373 Freezing rate 3 1 0.0003 0.0003 0.0121 Experimental error 46 1.1356 0.0246 Total 47 1.1359 Freezing rate*3 1 0.0227 0.0227 1.4551 Experimental error 46 0.7209 0.0156 Total 47 0.7436 3 part 1 of the regression line k part 2 of the regression line ft significance at 95% level rft significance at 99% level TABLE 8 COMPARISON OF THE SLOPE OF THE REGRESSION LINES FOR PART 1 OF THE REHYDRATION PROCESS AS INFLUENCED BY IRRADIATION LEVELS 0 Mrad 1 Mrad 3 Mrad 5 Mrad A B C D Slopea 0.1065 0.2658 0.2255 0.2584 mean value of 12 samples Duncan's New Multiple Range Test: B D C A B D C > A Means sharing the same underline did not differ significantly according to Duncan's New Multiple Range Test TABLE 9 COMPARISON OF THE SLOPE OF THE REGRESSION LINES (PART 2) AS INFLUENCED BY FRESH/DRY IRRADIATION SEQUENCE Irradiated Irradiated when fresh when freeze-dried Slopea 0.0920 0.1921 a mean value of 24 samples 29 significant difference between the slopes of the samples irradiated at 1, 3 and 5 megarad. Table 7 also shows that the "fresh-dry" irradiation sequence has a highly significant effect on the slope of the last part of the rehydration process, ("part 2" of the regression analysis - see Table B2, Appendix B). Table 9 shows that the regression lines for "part two" rehydration of samples irradiated after freeze-drying have greater slope than the samples irradiated when fresh. This indicates that the "part two" rehydration rate is more rapid in the sample irradated after freeze-drying than in the sample irradiated when fresh. Extract Release Volume (ERV) In this study, the analysis of variance shows no significant difference in ERV for different irradiation levels, freezing rates and "fresh-dry" irradiation sequences (Table 10). However the combined effect of irradiation level and fresh-dry irradiation sequence showed significant differences in ERV at the 95% level. Table 11 shows that the sample irradiated at 5 megarad after freeze-drying gave the lowest ERV. This result appears to indicate that the lower the moisture content, the less damage occurs during irradiation. ERV is normally measured on fresh meat of relatively uniform moisture content. In these experiments the ERV of rehydrated samples varying greatly in moisture content are being compared. For example, sample A may reach a moisture content of 65% (W.B.) while sample B reaches only 40% (W.B.) moisture content after rehydration. Usually the ERV obtained is higher in sample A and lower in sample B. Does this truly TABLE 10 ANALYSIS OF VARIANCE OF EXTRACT-RELEASE VOLUME OF RECONSTITUTED FREEZE-DRIEF BEEF: EFFECT OF IRRADIATION LEVELS, FRESH-DRY IRRADIATION SEQUENCE, AND FREEZING RATE Source DF Sum Sq Mean Sq F Prob Irradiation levels (A) 3 283.77 94.592 0.60 0.6243 Fresh-dry irradia-tion sequence (B) 1 243.36 243.36 1.54 0.2216 Freezing rate (C) 1 3.3075 3.3075 0.02 0.8573 AB 3 1489.6 496.53 3.14" 0.0382 AC 3 253.22 84.406 0.53 0.6659 BC 1 348.63 348.63 2.21 0.1435 ABC 3 483.57 161.19 1.02 0.3979 Error 32 5057.0 158.03 Total 47 8162.4 significant at 95% level TABLE 11 MEAN EXTRACT-RELEASE VOLUME (AVERAGE OF 6 SAMPLES) AS INFLUENCED BY IRRADIATION LEVEL AND FRESH-DRY IRRADIATION SEQUENCE 0 Mrad 1 Mrad 3 Mrads 5 Mrads Irradiated when A B C D fresh 61.8650 73.2317 64.0217 73.1250 Irradiated when E F G H freeze-dried 68.7283 65.4083 68.2217 51.8717 Duncan's New Multiple Range Test: B D E G F C A H B D E > H 32 indicate that the sample B has higher waste-holding capacity than sample A? These differences in water uptake serve to confound the ERV results, and will require further study. Shear Press The analysis of variance (Table 12) shows that irradiation levels have a significant effect on the shear press value of freeze-dried beef samples. Kramer shear values of meats are low for 5 megarad of irradiation compared to 1 and 3 megarad (Table 13). The freeze-dried samples subjected to 5 megarad of irradiation have a lower shear force after rehydration than do those subject to 1 or 3 megarad. The control sample (unirradiated sample) had the highest shear press value as com-pared to the irradiated samples. This results agrees with Bailey and Rhodes (3) that irradiation of meats causes a softening of texture. The change is small at low doses such as 1, 3 megarad, and increases with higher doses of irradiation. Bailey and Rhodes also stated that when a tender meat is subjected to irradiation, i t is not over-softened and that the irradiation at sterilizing doses has a beneficial effect in respect to texture on tougher types of meat. It can be seen from Table 12 that the "fresh-dry" irradiation sequence and the freezing rate show no significant effect: upon the shear press forces. However, their combined effect produces a significant difference. Sample frozen at -56.1°C (-69°F) and irradiated in the freeze-dried state gave a significant lower shear press value (Table 14). TABLE 12 ANALYSIS OF VARIANCE OF KRAMER SHEAR PRESS FORCE FOR REHYDRATED FREEZE-DRIED BEEF: EFFECT OF IRRADIATION LEVELS, FRESH-DRY IRRADIATION SEQUENCE AND FREEZING RATES Source DF Sum Sq Mean Sq F Prob Irradiation levels (A) 3 3910.3 1303.4 4.25* 0.0123 Fresh-dry irradiation sequence (B) 1 2.5669 2.5609 0.01 0.8890 Freezing rate (C) 1 909.85 909.85 2.97 0.0910 AB 3 1799.7 599.89 1.96 0.1391 AC 3 1028.8 342.94 1.12 0.3568 BC 1 1320.7 1320.7 4.31* 0.0438 ABC 3 1699.5 566.52 1.85 0.1572 Error 32 9814.0 306.69 Total 47 2048.5 ft significant at 95% TABLE 13 level MEAN KRAMER SHEAR FORCE VALUES FOR REHYDRATED FREEZE-DRIED BEEF IRRADIATED AT FOUR DOSE LEVELS 0 Mrad 1 Mrad 3 Mrad 5 Mrad A B C D Shear force a (lbs) 42.2083 27.3508 28.3108 16.8083 a average of 12 samples Duncan's New Multipl .e Range Test: A C B D A > C B D C > D Means sharing the same underline did not dffer significantly according to Duncan's New Multiple Range Test. 34 TABLE 14 MEAN KRAMER SHEAR PRESS FORCE VALUES3 FOR REHYDRATED FREEZE-DRIED BEEF SUBJECTED TO TWO FRESH-DRY IRRADIATION SEQUENCES AND TWO FREEZING RATES A B C D Shear forces (lbs) 28.0092 29.7925 38.0875 18.8392 average of 12 samples A o combined effect of slow freezing (-22.2 C) and irradiated when fresh ^ combined effect of slow freezing (-22.2°C) and irradiated when freeze-dried C o combined effect of rapid freezing (-56.1 C) and irradiated when fresh D combined effect of rapid freezing (-56.1°C) and irradiated when freeze-dried Duncan's New Multiple Range Test: C B A D C > D 35 CONCLUSIONS In this study, the effect of irradiation level, fresh-dry irradiation sequence and freezing rate on the extract-release volume, shear press force and rehydration were investigated. .1) The effect of irradiation level, fresh-dry irradiation sequence and freezing rate have no influence on the Extract-Release Volume (ERV) but the combined effect of irradiation level and fresh-dry irradia-tion sequence does affect the ERV. The samples irradiated after freeze-drying at 5 megarad level gave the lowest ERV. 2) The lowest shear press force was obtained by high doses (5 megarad) of irradiation. The control samples gave the highest shear press forces. The fresh/dry irradiation sequence and freezing rate did not affect the shear press measurement. 3) The irradiation level has l i t t l e effect on the final water absorbed by the freeze-dried beef. The fresh/dry irradiation sequence and freezing rate affect the water regained greatly. The highest total water uptake was found for the meat irradiated when fresh and frozen at -22.2°C (-8°F) temperature. 4) The mechanism of rehydration appears to follow a phenomena of water flow, not diffusion, which is similar to water flow in capillary tubes. There appears to be three mechanisms involved in rehydration, as shown by the fact that almost a l l log log curves were broken into two straight lines, and there is a very rapid i n i t i a l water absorption. No reasons can be found for the variation in slope and position of the curves for replicate samples. 36 5) Upon inspection of the part 1 of the slope of the re-gression lines i t can be seen that the unirradiated samples have a significantly lower slope than the irradiated samples. For the part 2 of the slope of the regression lines the samples irradiated when freeze-dried have significantly higher slope than the samples irradiated when fresh. 37 LIST OF REFERENCES 1. Auerback, E., H. Wang, N. Maynard, D.M. Doty, and H.R. Kraybill, 1954. A Histological and Histochemical Study of Beef Dehydration. V, Some Factors Influencing the Rehydration Level of Frozen Dried Muscle Tissue. Food Research 19, 557. 2. Bull, H.B., 1943. Physical Biochemistry. John Wiley and Sons, New York. 3. Bailey, A.J. and D.N. Rhodes. 1964. Treatment of Meats with Ionizing Radiation. XI. Changes in the Texture of Meats. J. Sci. Fd. Agric. 15, 504. 4. Coleby, J.B., M. Ingram, and H.J. Shepherd. 1961. Treatment of Meats with ionizing radiations, VI, Changes in quality during storage of sterilized raw beef and pork. J. Sci. Fd. Agric., 12, 417. 5. Doty, D.M. 1965. Chemical changes in irradiation meats. In -Radiation Preservation of Foods, National Academy of Sciences, National Research Council, Washington, D.C. 6. Fox, J.B., Jr., Theodora Strehler, Carl Bernofsky, and B.S. Schweigert. 1958. Production and Identification of a Green Pigment formed during Irradiation of Meat Extracts. J. Agr. Food Chem." 6, 692. 7. Fujimaki, M., N. Arakawa, and G. Ogawa, 1961. Effects of gamma irradiation on the chemical properties of action and actomyosin of meats. J. Food Sci. 26, 178. 38 8. Fujimaki, M., and Nakajima, Y. 1958. Chemical studies on the autolysis of meats. V. On the change of f i b r i l l a r and sarcoplasmic proteins during aging of meats. J. Agr. Chem. Soc., Japan 32_, 695. 9. Hamm, R. 1960. Biochemistry of meat hydration. In Advances of Food Research, 10, 355. 10. Harper, J.C., and Tappel, A.L. 1957. Freeze-drying of food products. Adv. Food Res. 7_, 171. 11. Harper, J.C, CO. Chichester, T.E. Roberts. 1961. Application of dielectric heating in freeze-drying of food. Presented at the 1961 Annual Meeting of American Society of Agricultural Engineering. 12. Hedin, P.A., G.W. Kurtz, and R.R. Koch, 1960. Production and prevention of irradiation odour in beef. Food Research 25, 382. 13. Huxley, H.E., and Hansan, J. 1957. Quantitative studies on the structure of cross-striated Myofibrils. I. Investigations by interference Microscopy Biochim. et Biophys. Acta 23, 229. 14. Jay, J.M. 1967. Response of the phenomena of extract-release volume and water-holding capacity to irradiated beef. J. of Food Sci. 32, 371. 15. Kuprianoff, J. 1958. "Bound Water" in foods. In Fundamental Aspects of the Dehydration of Foodstuffs. Society of Chemical Industry, p. 18. 16. Kirn, J.F., Urbain, W.M. and Czarnecki, M.J. 1956. Characteristics of electron-irradiated meats; Stored at refrigerator temperatures. Food Tech. 10, 601. 39 17. Kuprianoff, J. 1964. Fundamental and practical aspects of freezing of foodstuffs. In Lyophilisation, p. 497, Louis Rey (ed.) Hermann, Paris. 18. Koshland, D.E., and E.B. Herr, 1957. The role of water in enzymatic hydrolysis: general methods and its application to myosin. J. Biol. Chem., 228, 1021. 19. Luyet, B. 1961. Recent developments in cryobiology and their significance in the study of freezing and freeze-drying of bacteria. In Proc. Low Temperature Microbiology Symposium Campbell Soup Co., Camden, N.J. 20. Luyet, B.J. 1962. Effect of freezing rates on the structure of freeze-dried materials and on the mechanism of rehydration. Freeze-drying of Foods, p. 194. National Academy of Sciences, National Research Council, Washington, D.C. 21. Lawrie, R.A., J.G. Sharp, J.R. Bendall, and B. Coleby. 1961. Treatment of meats with Ionising radiation. VIII, pH, water holding capacity and proteolysis of irradiated raw beef and pork during storage, and the ATP-ase-. activity of irradiated rabbit muscle. J. Sci. Fd. Agric. 12, 742. 22. LeClerg, E.L., W.H. Leonard and A.G. Clark, 1966. Field Plot Technique. Burgess Publishing Company, Minneapolis,Mi nnesota. 55415. 23. Meryman, H.T. et al . 1962. Introductory survey of biophysical and biochemical aspects of freeze-drying. In Freeze-drying of Foods, Fisher, F.R. (ed.) National Academy of Sciences, National Research Council, Washington, D.C. 40 24. Nemethy, G. and Scheraga, H.A. 1962. Structure of water and hydrophobic bonding in proteins. III. Thermcriyrtamic properties of hydrophobic bonds in proteins. J. Phys. Chem. 66, 1773. 25. Nemethy, G. and Scheraga, H.A. 1962. Structure of water and hydro-phobic bonding in protein. II. Model for the therntoiynamic properties of aqueous solutions of hydrocarbons. J. Chem. Phys. 36, 3401. 26. Olcott, H.S., and Fraenkel-Conrat, H. 1964. Water resistance of protein. Ind. Eng. Chem. 3Js_, 104. 27. Pauling, L, 1945. The adsorption of water by protein. J. Am. Chem. Soc. 67_, 555. 28. Schmidt, CF. 1963. Appendix II, Dose requirements for the radiation sterilization of food. Int. J. Appl. Rad. and Isotopes, 14, 19-26. 29. Sparrman, B., L. Ehrenberg, and A.E. Ehrenberg. 1959. Scavenging of free radicals and radiation protection by nitric oxide in plant seeds. Acta. Chem. Scand. 13_, 199. 30. Smithies, W.R. 1962. The influence of processing conditions on the rehydration of freeze-dried foods. In Freeze-drying of Foods. National Academy of Sciences, National Research Council, Washington, D.C. 31. Steely R.G.D. and J.H. Torrie. 1960. Principles and procedures of statistics. McGraw-Hill Book Company, Ing. N.Y. 41 32. Urbain, W.M. 1965. Radiation preservation of fresh meat and poultry. Radiation preservation of foods, p. 87. 33. Whitehair, L.A., R.W. Brag, K.G. Weckel, G.W. Evans, and F. Heiligman, 1964. Influence of intramuscular fat level on organoleptic, physical and chemical characteristics of irradiated pork. I. High-temperature short-time pre-irradiation heat treatment. Food Tech. 18_, 108. 34. Week, B.M., and W.M. Garrison. 1958. Rad. Research £, 291. 35. Wierbicki, E., M. Simon, and E.S. Jose Fhson. 1965. Preservation of meats by sterilizing doses of ionising radiation. Radiation Preservation of foods, p. 383. 36. Wedemeyer, G., and A.M. Dollar. 1964. The role of Free and Bound water in irradiation preservation: Free radical damage as a function of the physical state of water. J. of Food Sci. 29, 525. 42 APPENDIX A 43 TABLE Al WATER LOSS DURING FREEZE-DRYING AND FINAL WATER CONTENT OF THE FREEZE-DRIED BEEF FOR ANIMAL NO. 6868 (GROUP A) Treatment Fresh wt. Weight after Water loss Freeze-dried number <g) freeze-drying (D.B.)% M.C. (D.B.)% 1 83.62 21.26 300.78 2.55 2 79.12 17.77 355.55 2.99 3 68.09 20.22 242.90 2.63 4 73.19 19.59 287.22 4.98 5 78.61 21.13 289.91 6.58 6 71.27 18.74 288.86 3.06 7 69.66 17.41 308.98 2.96 8 76.10 21.33 281.83 9.76 9 84.70 20.82 316.14 3.04 10 78.96 19.96 312.63 5.77 ., 11 65.90 16.57 315.86 6.11 12 67.08 16.80 308.60 3.12 13 71.41 18.08 302.43 2.54 14 73.23 18.70 298.56 2.39 15 62.67 15.92 301.06 2.53 16 60.19 15.59 294.08 2.80 Average fresh sample moisture content = 292.17% (D.B.) TABLE A2 WATER LOSS DURING FREEZE-DRYING AND FINAL WATER CONTENT OF THE FREEZE-DRIED BEEF FOR ANIMAL NO. 6852 (GROUP B) Treatment Fresh wt. Weight after Water loss Freeze-dried number (g) freeze drying (D.B.)% M.C.(D.B.)% 1 80.06 21.88 g 272.76 2.67 2 91.70 24.25 284.80 2.40 3 90.28 23.67 289.45 2.86 • 4 68.37 18.01 288.21 3.08 5 67.88 17.93 291.01 4.47 6 86.43 22.37 296.50 3.55 7 89.38 25.14 262.91 2.90 8 70.70 18.80 287.65 4.20 9 68.04 17.69 293.91 3.27 10 62.50 16.31 295.49 4.35 11 58.95 15.47 294.15 4.66 12 69.01 18.30 289.61 4.52 13 74.89 19.98 286.69 4.32 14 77.13 20.54 287.77 4.45 15 63.77 16.63 295.73 4.33 16 61.63 17.66 288.21 3.94 Fresh sample moisture content = 299.74% (D.B.) TABLE A3 WATER LOSS DURING FREEZE-DRYING AND FINAL WATER CONTENT OF THE FREEZE-DRIED BEEF FOR ANIMAL NO. 6852 (GROUP C) Treatment Fresh wt Weight after Water loss Freeze-dried number (g) freeze-drying (D.B.)% M.C. (D.B.)% 1 2 95.90 25.90 280.42 3.76 3 57.98 15.15 299.41 5.91 4 93.88 24.76 290.91 4.22 5 78.73 20.89 290.47 4.91 6 76.26 20.73 283.52 5.85 7 62.18 16.25 315.03 11.46 8 64.48 17.17 293.03 6.35 9 80.17 21.75 283.18 5.44 10 75.38 19.59 299.71 5.25 11 74.60 19.60 294.54 4.97 12 82.76 21.69 308.52 9.58 13 75.29 19.58 299.53 5.28 14 52.70 14.03 292.78 6.23 15 86.76 23.07 290.51 5.23 16 72.31 20.17 271.73 5.13 Fresh sample moisture content = 299.74% (D.B.) 46 APPENDIX B 47' - 1 . 2 - 0 . 6 0.D 0.6 1.2 1.8 2 .4 L O G T I M E . M I N U T E S FIGURE 5. Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 1, 2, 3, and 4 represents sample 1A, 2A, 3A, and 4A resp e c t i v e l y . 48/- v-, - - - - r - - - - -- - - ... - - - - - -- ~1 r VI - - - - - • - - -- - — — - --... - - - 1 r r - -— -— ... - - — -- - -- - - - - -- - - - - - — - - - - — - - - -L r r si -- - --- - - - - -- - - ... - - - - I ! 1 i | - t ---- . . . - - - - - ... -_ - -- j - - ... - ._]_. 1 - - —i—| - - ... -- --- - - - - _ i ! _ l - -- - - - ... - --I - - -- - -- 1 '- - -\<Sf - ~! •> - - - - - - -- - - -- -- - - - ... • t ... - - i rf -- - - >- -- - -- - -j - -a 1 - - -Ai r ^) u o i -- - i - - -1 L i f - If -( — l 1 — 1 -—• i 1 i 1 t |C -r i J . -J -- -I 1 ~i - -[ 1 • y --i I ;t n •r 2 - - -- 1 1 • >- i - -C 1 > 3 1 / > T 1 -I r. — E r j . > I- r I _ _ i - 4 t - -- < — \ r — - \ J i - '- -i c y ft - -- - — = ) L - > / l ) i - S --- <— - - - - - N J, - c ) - / --- — - — - ... - — - - ... - -- -t - - - - - - - - ... - - - -- - ... - - -— -1.2 D.B 0.0 0.6 L O G T I M E . M I N U T E S 1.2 1.8 2.4 FIGURE Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 5, 6, 7, and 8 represents sample 5A, 6A, 7A, and 8A r e s p e c t i v e l y . 4 9_>-LOG TIME.MINUTES FIGURE 7. Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 9, 10, 11, and 12 represents sample 9A, 10A, 11A and 12A resp e c t i v e l y . 5 0 - - -- - - - - -- . . . -- - . . . . . . -- -- - - - . . . -- - . . . --- '4 - - -- - - --- - - -. . . -- . . . --- •-— -- - -. . . -- -- - — - --• - . . . - -- - - -- - -- --— -- --- -- - - - - - . . . - --• -- - - - . . . - - - -- . . . . . . - - - -- -- -- --- . . . - -_ -— -- - „r - — -- -- - - . . . - - _ - - -- - -- - -i- -- -- ---- — i " " ! — - -- - -- -- - - - - - --- - \ .71 - - - - - . . . -— - - - - - - -- - - - •- -. . . - - . . . - --- -— - - --- - . ._ - - - - - - - - - -— - — L -i / 1 ~ r -- -- - -1 ( - - - / '--- - L — - - - L - -- - - --- -U >t .c - -/ VI 3 -J r. - — - J r VI ( A ! / / - 1 t 7 / i 1 i A i ix: n / / U L . Li 11 J / H •f - --t l I f \ 1 - -- / A. 1- 1 / in • -J -j - - — - -fir? -- . . . - - - -- -- -> TT > -/ -is -m tu •) V f i —> [ A » p 1 B - - -> tj J i _1-J f - 1 A -< V --D 1 - l r r y 1 _ --, -_ u - 1-- _ -• - h. - ... A > - - -/ -• / • - -- S --- - - - - ---. . . - -- -_ - - - -— -. . . ---. . . -- - - _ - - --- - . . . - - - ---1.2 -0.6 0.0 "0.6 L O G T I M E . M I N U T E S 1.2 1.8 2.4 FIGURE 8. Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 13, 14, 15 and 16.represents sample 13A, 14A, 15A, and 16A resp e c t i v e l y . 51, 1 ---1 ---- - -. . . - --- -. . . - - . . . IT". - - - . . . . . . _ L - - . . . - - . . . - 1 1 .„J_L -I+ H - -- - — - — -- -- — — - -— --- — — . . . — — — — — — — — — — tr ""i • i 1 1-r t— -- — - _ — - -- ----_. ---------- -- — - . . . - . . . -— -- - -- - -• - ---- t *f — - — _ — — — — — _--.r»> - -- - - -- -r M - --.r - -- --- - - - - - -- - - --- - --„ - - -7 - -. . . - --- -_ -— . . . . - . . . - ---— - - - ... if -- -- -- - ---- - - -- - ---— -— - -- --— -— - -- --L p — - - -- --- - - - --- - - - . . . - J 0 - > > - - - --- — - - - - - -- * -— /---_ --L U •) - -.r ,.r < - L , - ---J ~j I.r - - - - -— -j i -f > - - -[ I t v |C D I j. 1— pi -- - -I J_ T 1 -1 - -1 1 1 3 > . =•11 •r ir 1 -i i i i 1 \ r — - - -- - -- -J i -- -( -1 j -- A i - — ) / \ 1 i h f \ - - -- - - - —> r— - "F- - • — --J. - i L VI 1 - | A -a - - ( < T -J - - \ -- - -4 -- =-1 - — - / \ J -- - / -- -- -- - - - - - - - - --t - - - — - -. . . - . . . -- - - -- ---- -—« 1 - 1 . 2 - D . B 0 .0 ' 0 . 6 1.2 1.8 2 . 4 L O G T I M E . M I N U T E S FIGURE 9. Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 17, 18, 19, and 20 represents sample IB, 2B, 3B, and MB resp e c t i v e l y . 5 2' -• - 4 ^ 3-T — - - - 1 ... 4 : - ... - - r - :I_L_ _L - - | ..... -- 1 i 4 -1 " r T " ! 1 : — ---I VI --± 1 ... -4 -- -I i • — t 4 : -- - i ---... ...L : 4 : b - --1 I " i " r _ — .... —r— - -—; ... ... .... r _.)._ f 'ii 1 -1 u r •> - - _: - ... - ... - ... - ... - ... ... : - - ... —1> Of "4 ; * • • r • - ... - - - — --._ - - ii-. - - — - r ' i T r --_ r VI --- ---- - ... - - --- ... ---- - ._ - -!-4 M _ . . ---— i F r - - - - ; i : "1 i i i j j_ — - — - - ... ~ - -j i i r —— - L •) - - — - - — - i i r r - - - - - .... - -- i - - ... Hi !_ 1 I i r i - r - - -- - -- -— -- — - . - - — --! i i - - - - - - 1 is — - - - - / - - -- - ---.... - - -4 -I --- - - -- i - - - - - — -I i u - - -• i - r - -- - - — — ^- -ca ' i« - - .... - ... .... . . . -- 1 ! .1 -- ... - i i : - -—f -- - -- i i : 4—! — -I - -- u _ u I -- i i ! n i i- i ; - } -4 Bt U--^ £ - \ 7 i - / - i j ; — I -C r r ) _< .... i : i . . . . 1 - 1tH- -- - i - - - - -I - h - - - --— - i 1 j i : - JOJT -- - ! I ! - -- .... LL. --14 -fe • ! - - - - -- - - j --CHJ£> : i t e : -- [ i - - ! i A - ! ! ! , i i • -_ i --i - ... — . . . -- - ... - - - --! i ' — - - - -- - ... -] i - e - - - P : I - ... .... - - - ' i ' P ! • ; T 1 - -- - - j_ 1 ! •• -- -- t | ! ! " - - - - - - -- - - — T ^ t -| ! ; ; — --- ... M _ ! ' —i t \ - _ - - - / \ 1 1 -- -I - j - - - --- j - : . - - —--- < " F ! - - - - - - ---- - > D" \ i i i j -— 3. ... g: -- ! — - ru - - - - -- > —>. - — a - -- U T K - --... p. pi - -- - - _.. - - - - - -- -4- S - ---. . . - -s - 1 1 j i _ L -I-i i n -14 - - - - - - -5^ - X" " 1" / - - - ! I - - .._ -- - -- ~< -.! ! i i . i : - - --- - - --- - ---- - - - - -X ... - -! 4-1 i - - ... - - __. -- 1 >i 1 - - - — - - — --... U -- _.[._ --- ... ... - - - -- -- -- -- _[_. ..... .... - - -- 1 . 2 - 0 . 6 0.0 0.B 1.2 1.8 2 . 4 L O G T I M E . M I N U T E S FIGURE 10. Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 21, 22, 23, and 24 represents sample 5B, 6B, 7B, and 8B resp e c t i v e l y . •+ 0.0 0.6 LOG TIME.MINUTES 1.2 1.8 2.4 FIGURE l l . Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 25, 26, 27, and 28 represents sample 9B, 10B, 11B, and 12B re s p e c t i v e l y . -1.2 -0.6 0.0 0.6 1.2 1.8 2.4 LOG TIME.MINUTES FIGURE 12. Logarithm of water uptake versus logarithm time f o r i r r a d i a t e d freeze-dried beef: Set 29, 30, 31, and 32 represents sample 13B, 1HB, 15B, and 16B resp e c t i v e l y . LOG TIME.MINUTES FIGURE 13. Logarithm of water uptake versus logarithm time f o r i r r a d i a t e d freeze-dried beef: Set 33, 34, 35, and 36 represents sample 2C, 3C, 4C and 9C r e s p e c t i v e l y . + A A SET 37 + SET 38 X SET 39 <^ SET 40 -1.2 -0.6 0.0 0.6 LOG TIME.MINUTES 1.2 1.8 FIGURE 14. Logarithm of water uptake versus logarithm time f o r i r r a d i a t e d freeze-dried beef: Set 37, 38, 39, and 40 represents sample 10C, 11C, 12C, and 5C re s p e c t i v e l y . ru in rsi ru' i n —J ru" in »ru C3 CQrvj o L U CHI-LLI CM o + X A CD in A SET 41 + SET 42 in ru in —i X SET 43 -<3-o SET 4 4 - 1 1 1 1.2 . - 0 .6 D.O 0.6 LOG TIME.MINUTES 1 1.2 1 1.8 FIGURE 15. Logarithm of water uptake versus logarithm time f o r i r r a d i a t e d freeze-dried beef: Set 41, 42, 43, and 44 represents sample 6C, 7C, 8C, and 13C respe c t i v e l y . A SET 45 + SET 46 X SET 4 7 1 1 0.0 0.B LOG TIME.MINUTES -1.2 -0.6 1.2 1.8 FIGURE 16. Logarithm of water uptake versus logarithm time for i r r a d i a t e d freeze-dried beef: Set 45, 46, and 47 represents sample 14C, 15C, and 16C r e s p e c t i v e l y . ( $ R U \ E X E C U T I O N B E G I N S N T I T I F A 8 R VB YE 1 2 SET1 PART 1 2.317C 0.C537 0.9990 ?.?633 2 . 3 6 9 7 S t :T? P ART 1 2.2662 0.1658 0.9983 2. 1CC4 2.3777 SCT 3 »ART 1 2.100" 0.2469 0.9996 1.8639 2.1591 ~ " q SF T 4 -, A P. T 1 1,861') 0.2899 0.9955 1.86 19 2.2ft 71 1 s SCT 6 2. 103? 0.1366 0.99R6 ?.1?31 2 . 3 4 6 4 15 SET (, 2.1227 0. 1C9C 0.999? 2 . 0 9 8 6 2.3 0 35 3 s n 7 P A I T 1 1.9') 14 0.4718 0.9980 1.519ft 2 . 0 2 8 8 I a SI T 8 ' ! i 1 1.7137 0.286 1 0.9992 1.7 364 2.1146 1 5 .',!- T '/ 2 .2 79 4 0.0630 0.99 71 2 . 2 3 5 3 2 . 3 8 9 6 8 SC I 1 0 PART 1 I.046 3 0.723C 0.9990 1.391 3 2 . 2 C 4 6 3 SCT 1 1 PART 1 1 .4 368 0. 18B2 0 . 9 9 9 9 1 . 5 6 8 3 1 . 6 5 9 ' ? 8 SCT 1 2 HART 1 1.4 54 5 0.40C3 0.998? 1 . 7 3 4 3 2 . 1 1 6 2 ') SET 13 PART 1 1.7773 0.2965 0 . 9 9 9 8 1 . 7 7 2 3 2 . 1 8 6 8 6 s n l ' i PARI 1 1.2 07 3 0.64 8 4 0 . 9 9 79 1 . 6 1 6 7 2 . 1 1 3 7 ) M l I -. PARI 1 1. 7384 0 . 34C2 0 . 9 96 3 1 . 7 3 8 4 2 . 14 8 C 14 SET ! • 1 . o n 3 0.5098 0 . 9 8 9 8 1 . 3 3 6 5 2 . 1 0 1 6 '-> SCT ) 7 ' , •' 1 1 2 . 1 5 4 3 0 .1470 0 . 9 99 7 2 . C 7 74 2 . 3 C 1 3 4 SCT l •' PARI 1 2,0*70 0 .1662 0 . 9 9 9 0 2 . 0 6 70 2 . 2 2 32 , 5 K F U 1 9 PAR f ! 2 . 1 8 5 3 0.1698 0 . 9 9 5 ? 2 . 0 2 5 5 2 . 3 4 5 1 4 S'* T ?'.) P A R I 1 2.126 1 0.2RC2 0 . 9 9 8 9 1 . 8 4 5 9 2 . 3 2 19 9 Sf' T 2 1 ? .179f t 0. 1025 0 . 9 9 9C 2 . 1 7 9 6 2 . it ?C 9 S c T 2 > 1.95 6 7 0 . 2 0 0 5 0 . 9 9 70 1 . 9 6 5 7 2 . 3 1 3 7 Si 1 2 3 1 . 9 2 4 6 0 .2403 0 . 9 9 71 1 . 9 2 4 6 2 . 3 60 2 4 SC 1 ?4 HART 1 2.1617 0.215C 0 . 9 9 6 8 1 . 9 3 6 7 2 . 3C2C 4 SCT 2-5 " A R T 1 2 . 1 8 4 2 0.1151 0 . 9 9 9 3 2 . 0 6 9 1 2 . 2 6 4 6 << S: T 2 6 PART 1 1 . 8 0 8 C 0.45C9 0 . 9 9 9 ? 1 . 3 6 7 1 2 . 1 2 3 2 r s r T ? 1 PARI 1 1 . 9 7 1 3 0.2299 0 . 9 9 6 1 r. 7414 2 . 3 I C 9 b SI i 2 H PARI ! 1 . 7 2 4 0 0.3506 0 . 9 9 8 6 1 . 72 40 2 . 2 4 1 7 \ > SET 2 Q 2.1 52 I 0.0744 0.9935 2 . 1 3 2 1 2 . 2 H 4 C b 5E T TO PART 1 1.7F.9 1 0.3487 0 . 9 9 3 7 1 . 7 6 9 1 2 . 3 04 1 t l SCT 11 PART 1 1.6C05 0.2C5C 0.9995 1 . 6 C C 6 1 . 74 3 8 4 SI i 4 2 P !\ R T 1 1 . 5 3 6 7 0.1489 0.9844 1 . 5 3 6 7 1 . 6 8 4 5 5 Si 1 p \ << I 1 2 . 1 4 1 4 0.1346 0 . 9 9 9 0 2 . 1 4 1 4 2 . 3 1 6 3 4 SC T }4 PA ' r i 2.103 9 0.3338 0 . 9 9 8 9 1.7 7C 1 2.3373 4 SI I 10 PART 1 2.045? 0.2804 0 . 9 9 8 9 1 . 7 6 4 9 2 . 2 4 12 10 s c r 3ft 2 .166f t 0.0818 0 . 9 9 8 8 2 . 1666 2 . 3 1 7 6 6 SET 3 7 PART 1 1.9 30 3 0.0784 0 . 9 9 1 3 1 . 9 3 0 3 2 . C 4 6 1 Sf T 3H 1'. : T ! 1 .9619 0.C6 31 0 . 9 7 ? 3 1 .96 19 ? . C 2 5 C 3 SI ! 19 PART 1 2 . 067 9 0.1085 0 . 9 9 0 9 2 . 0 6 79 ? . 14 3 8 1 2 c \z r AO 2 . 2 1 3 C 0 . 0 4 6 2 0 . 9 5 7 0 2 . 1668 2 . 2 5 ) 7 SET 1 2 . 0 8 4 4 0 .094? 0.99 76 ? . 0 8 4 4 2 . 2 6 1 8 9 S r T / t 2 2 . 2 0 7 7 0 .0696 0 . 9 964 2 . 2 0 7 7 2 . 3 3 1 4 8 SET 'i 7 2.1170 0.1291 0 . 9 9 5 ? ? . 1 170 2 . 3 3 06 9 SCT 44 2 . 2 4 R 9 0.0604 0 . 9 9 2 7 2 . 2 4 8 9 2 . 3 6 6 4 10 SC T /, *, 2.0800 0.0705 0 . 9 7 2 6 2 . 0 C 9 5 2 . 2 C 2 7 1 SET 4 6 PART 1 2 . 1 HR ft 0 . 1 5 7 6 0.9995 2 . 1 186 2 . 2 4 E 8 I I SET 47 2.0 39 7 0.1025 0.9929 2 . 0 3 9 7 2 . 2 3 4 6 'f3k m TABLE B l . A n a l y s i s o f p a r t 1 r e g r e s s i o n l i n e s f o r r e h y d r a t i o n o f f r e e z e - d r i e d beef. The i d e n t i t y o f i n d i v i d u a l " s e t s " i s the .nue as used on the graphs (see F i g u r e s 5-1P). A i s the i n t e r c e p t o f the r e g r e s s i o n l i n e ( l o g tirr;e = 0) ; B i s t h e sl o p e o f the r e g r e s s i o n l i n e ; R i s the c o r r e l a t i o n c o e f f i c i e n t ; YB i s the i n i t i a l p o i n t on the r e g r e s s i o n l i n e ; YE i s the f i n a l p o i n t on the r e g r e s s i o n l i n e . ( EXfXlJ 1 ION KG IMS > N T l T I F A B P. ye Y f f 4 S P T 1 P A K T 2 2.354C 0 . 0 18 C 0 . 9 9 5 5 2.3749 2.3805 4 sifi r 2 2 A R T 2 2.3 31 7 0 . 0 5 5 0 0.94 9 7 2.3732 2.3889 I 10 Sri < P A R T 2 2.152 9 0 . 1 1 '. 1 0.9952 2.2275 2. 3 376 J f 7 f 1 T 4 i ' A r t f 2 2.0976 0. 128 1 0.9915 2.2869 2.334 1 S S E T ') 2. 1032 0.1365 0.9986 2.1231 2.3464 15 SF r 6 2. 122 7 0.109C 0.9992 2.0986 2 . 3 0 35 1 ) 7 l J AKT 2 2.0497 0.1217 0 . 9 9 •! 3 2. 1 6 0 2 2.3284 l> SC T 8 f* ART 2 1 .8634 0. 1865 0.9 9 74 2.1519 2 . 2 1 3 4 1 i S E T ') 7.2794 0.C6 3C 0.9971 2.2353 2.3 8 9 6 7 SI I ! 0 i> \". 1 2 1 .6889 0.3214 0 . 9 9 1 3 2.2 350 2 . 3 4 7 6 12 C T T 1 1 1' *\ '< T 2 1.0826 0 . 4 4 3 2 0.9966 1 . 7 3 7 2 1 . 9 9 9 2 7 SE 1 1 2 r , A K T 2 1.7 321 0.2 36 3 0 . 9 9 1 5 2.1435 2 . 2 0 9 9 6 SH! T 1 P l\ K T 2 2.0">72 0. 1008 0.9824 2 . 2 0 6 1 2 . 2 4 3 2 it s r T l ' l ' A ! ' . r 2 1.7060 0.2985 0 . 9 9 7 1 2 . 1 6 6 9 2 . 3 0 2 9 (. • >' ' 1 i' \ ' 1 2 1.9811 0.1541 0 . 9 9 9 0 2 . 1 8 3 6 2 . 2 U 4 3 PS •: i i 11 I .093 3 0.5098 0 . 9 8 9 8 1 . 3 3 6 5 2 . 1C 11 5 sr T 1 1 PAKT 2 2.2438 0.0672 0 . 9 9 6 5 2 . M i l 2 . 1 6 0 6 6 s r i 1 « 7.1175 0.1311 0 . 9 8 8 7 2 . 2 8 8 0 2 . 1 5 6 9 4 SI 1 1 l I'AIU ? 2.325 7 0.0 27 1 0 . 9 8 3 0 2 . 3 6 0 9 2 . 3 7 0 9 r £ | . 1 ;' 2.3166 0.0220 0 . 9 9 2 1 2 . 3 3 8 6 2 . 3 6 3 0 9 S E T 2 ! 2.1796 0.102 5 O . S 5 9 0 2 . 1 7 9 6 2 . 3 6 2 0 9 S " 1 ?2 1.9*67 0.2005 0 . 5 5 7 0 1 . 9 6 5 7 " 2 , 3 1 3 7 9 SFT 1 l 1 .9246 0.2403 0 . 9 9 / 1 1 . 9 2 4 6 2 . 3 5 0 2 5 S f 1 24 l " \ K T 2 2.2882 0.0351 0 . 9 9 1 9 2 . 3 2 3 3 2 . 14 7 8 SF T ?5 PAKT 2 2 . 2 3 7 0 0.0400 0 . 9 9 7 9 2 . 2 7 / 0 2 . 3 0 8 1 l i SF T V - • • • ; 2.1 20 4 0.1364 0 . 9 6 Pt 1 2.2568 2 . 3 5 2 1 1 SF r PART 2 2.2370 0.056C 0 . 9 9 6 3 2 . 3 2 6 7 2 . 3 3 6 6 1 " i . - i 1.9974 0. 1750 0 . 9 9 76 2 . 2 7 2 7 2 . 3 3 9 2 1 5 si r ? 1 2.1 321 0 .074 4 0 . 9 9 3 1 2 . 1 3 2 1 2 . 2 8 4 0 1; 9 SF T 1 1 • • • ' .' 2.1)72 0.0734 0 . 9 2 6 2 2 . 31 4 7 2 . 14 69 10 S r T t 1 1 \ I 1 . 3 3 3 5 0.4900 0 . 9 9 8 6 1 .8 2 8 5 2 . 3 1 8 5 1 1 SFT • . ••: ' 1.1531 0.4833 0 . 9 9 7 r . I, 7 8 1 9 2 . 1 19 7 4 • ' . \ " r 2 . 2 1 2 9 0.0637 0.9856 2 . 3 3 2 2 2 . 1 4 6 4 10 SI ' 2 . 3 33 0 0.0187 0.9820 2 . 3 5 1 7 2 . 1 7 0 4 ') SF T 3 '• PAKT 2 . 2.2 192 0.0596 0 . 9 8 4 8 2 . 2 9 8 8 2 . 3 5 5 8 10 Sf T 16 2.1 (.6 (t 0.0818 0.9988 2 . 1 6 6 6 2 . 1 3 1 / 6 6 s r T PACT 2 I .7 800 C.1833 0.9556 2 . 0 7 3 7 2. 1 38 3 8 SI T P \ <l .' 1 .P.02 >J 0 . 2 1 0 <t 0.959! 2 . 0 7 6 6 2 . 2 2 3 7 7 S F T 3 9 PAKT 2 2.0 IB1) 0 . 1803 0.9585 2 . 1 9 8 8 2 . 1 5 1 2 12 St T '.II 2.2130 0.0462 0 . 9 9 7 0 2.1668 2 . 2 9 9 7 9 SI. 1 4 ! 2.0844 0 . 09 4~2 "0 . 9 9 76 2 . 0 8 ' . ' , " 2 7 2 5 1 H 9 SE- T 4 2 2.2077 0.0696 0 . 9 9 6 4 2 . 2 0 7 7 2 . 3 3 1 4 8 err 4 3 2.1170 0.129 1 0 . 9 9 1 2 2.1170 2 . 3 3 0 5 9 SF T ' . 4 2.2489 0.0604 0 . 9 9 2 r 2.24 8 9 2 . 3 5 6 4 1 0 S E T A S 2.0R00 0.0705 0 . 9 7 2 ' i 2.0C95 2 . 2 C 2 7 10 S T T ' . l ' l PftflT 2 2.218 1 0.0659 0 . 9 9 6 9 2.2840 2 . 3 4 8 5 1 I SF T ', ! 2.039 7 0.1025 0 . 9 9 7 9 " ~~ TT.TTVTT 7.7348 T A B L E B2. Analysis of part 2 regression lines for rehydration of freeze-dried beef. The identity of individual "sets is the sfl^ " as used on the graphs (see Figures 5-16). A is the intercept of the regression line (log time = n ) ; B is the slope of the regression line; K is the correlation coefficient; YB is the i n i t i a l point on the regression line; YE is the final point on the regression line. 61 APPENDIX C TABLE CI EXTRACT-RELEASE VOLUME OF THE REHYDRATED BEEF SAMPLES Group A Treatment Extract-release Treatment Extract-release number volume (ml) number volume (ml) . 1 64.88 12 50.60 2 84.25 13 63.75 3 65.75 14 73.75 4 77.00 15 69.38 5 77.25 16 67.50 6 66.36 7 73.38 8 73.00 Group C 9 66.75 10 37.50 1 11 40.00 2 84.38 12 40.00 3 43.75 13 76.25 4 75.00 14 73.75 5 71.25 15 66.25 6 65.60 16 27.50 7 77.50 8 75.00 9 57.50 60.00 1 60.00 11 46.25 2 77.50 12 58.75 3 77.50 13 71.87 4 79.40 14 71.25 5 48.75 15 80.00 6 66.88 16 50.63 7 77.50 8 75.60 9 62.50 10 70.60 11 76.20 Group B 1 Q TABLE C2 SHEAR PRESS VALUE OF THE REHYDRATED BEEF SAMPLES Treatment Kramer shear Treatment Kramer shear number press (lbs) number press (lbs) Group A 1 42.95 12 5.81 2 6.74 13 58.19 3 27.81 14 10.19 4 27.75 15 6.25 5 25.63 16 4.44 6 36.44 7 35.31 8 27.19 Group C 9 50.75 10 16.19 1 11 109.17 - 2 45.88 12 18.13 3 24.94 13 32.00 4 18.38 14 7.19 5 58.25 . 15 8.56 6 45.63 16 21.25 7 12.82 8 17.94 9 31.31 Group B 10 24.38 1 36.06 11 18.44 2 34.69 12 5.31 3 12.68 13 28.56 4 11.44 14 16.56 5 23.13 15 5.62 6 71.25 16 27.25 7 42.31 8 16.81 9 72.88 10 13.07 11 35.81 

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