- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Effect of spoilage and processing conditions on the...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Effect of spoilage and processing conditions on the nutritive value of various marine protein sources for rainbow trout (Oncorhynchus mykiss) and chinook salmon (Oncohrynchus tshawytscha) Clancy, Gordon Sean
Abstract
This study was undertaken to assess the nutritional value of fish meals (Pacific herring, Clupea harengus pallasi) and protein hydrolyzates (ocean perch, Sebastes alutus) processed in different ways for chinook salmon (Oncorhynchus tshawytscha) in salt water and for rainbow trout (Oncorhynchus mykiss) in fresh water. Three levels of raw material freshness (fresh frozen, moderately spoiled and highly spoiled) and two processing temperatures (low and high) were employed in the present study. Spoilage of Pacific herring stored at 2-5°C, as determined by the levels of total volatile nitrogen(TVN) and trimethylamine(TMA), was slow for the initial 8 days but increased rapidly until day 15. The direct distillation method with MgO yielded significantly higher TVN values than the microdiffusion method with K₂CO₃ or KOH and the steam distillation method with NaOH. The TMA values also varied with the method employed. For the routine determination of TVN and TMA microdiffusion with K2CO3 is recommended. The levels of putrescine and cadaverine in herring also increased rapidly after 8 days of storage at 2-5°C. Histamine levels remained low (<5.0 ppm), even after 12 days of storage. Prefreezing of the herring prior to storage at chill temperatures may have delayed the formation of histamine. The levels of putrescine, cadaverine, histamine, TMA and TVN were lower in the press cake meals than in the raw material, which was possibly due to amine losses in the press liquor and thermal degradation of amines. Elevation of processing temperature from 75°C to 100°C had little effect on spoilage indicator levels but did increase the amount of press liquor released from the raw materials. Progressive spoilage of the raw materials also increased the yields of press liquor and concomitantly decreased the yields of fish meal. The levels of TVN, TMA, putrescine, histamine and especially cadaverine were considered to be useful in determining spoilage of the raw material but only the less volatile amines (putrescine, cadaverine and histamine) may prove useful in predicting the quality of fish meal. Spoilage of the raw material, regardless of the protein source, adversely affected apparent digestibility coefficients for organic matter, gross energy and digestible energy content in chinook salmon and rainbow trout. As spoilage of the raw material increased, digestibility values decreased. Protein digestibility values were least affected by the degree of spoilage. Since fish meals contain high levels of protein and lipid but almost no carbohydrate, the probable cause of reduced organic matter digestibility of spoiled protein sources was depression of lipid availability. Elevation of processing temperature did not adversely affect digestibility values in either species. Differences in digestibility values were noted between species for meals produced from highly spoiled raw material and freezedried material. Rainbow trout seem to be more sensitive than chinook salmon to spoilage of the raw material as digestibility values of the meals produced from spoiled raw material were more severly depressed in rainbow trout. Lipid oxidation may have accounted for these differences, as chinook salmon recently transferred to sea water may be susceptible to quality of dietary lipids. Ocean perch hydrolyzates were highly digestible in both chinook salmon and rainbow trout. Pepsin solubility was greater than 98% regardless of processing and spoilage conditions. The pHstat values (utilizing enzymes extracted from rainbow trout), increased as spoilage of the raw material progressed but were slightly reduced in the high temperature meals. The pepsin solubility values also increased as spoilage of the herring protein sources progressed. TVN and TMA showed little promise as methods for predicting the nutritive value of ocean perch hydrolyzates or herring fish meals, although monitoring TVN and TMA levels in the raw material is recommended. However, the relationship between levels of putrescine, cadaverine and histamine may prove useful in determining the quality of fish meal. In conclusion, advanced spoilage of raw material (> 8 days for herring and ocean perch stored at 2-5°C) before processing resulted in depressed digestibility values in both rainbow trout and chinook salmon.
Item Metadata
Title |
Effect of spoilage and processing conditions on the nutritive value of various marine protein sources for rainbow trout (Oncorhynchus mykiss) and chinook salmon (Oncohrynchus tshawytscha)
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
1992
|
Description |
This study was undertaken to assess the nutritional value of
fish meals (Pacific herring, Clupea harengus pallasi) and protein
hydrolyzates (ocean perch, Sebastes alutus) processed in different
ways for chinook salmon (Oncorhynchus tshawytscha) in salt water
and for rainbow trout (Oncorhynchus mykiss) in fresh water. Three
levels of raw material freshness (fresh frozen, moderately spoiled
and highly spoiled) and two processing temperatures (low and high)
were employed in the present study.
Spoilage of Pacific herring stored at 2-5°C, as determined by
the levels of total volatile nitrogen(TVN) and trimethylamine(TMA),
was slow for the initial 8 days but increased rapidly until day 15.
The direct distillation method with MgO yielded significantly
higher TVN values than the microdiffusion method with K₂CO₃ or KOH
and the steam distillation method with NaOH. The TMA values also
varied with the method employed. For the routine determination of
TVN and TMA microdiffusion with K2CO3 is recommended.
The levels of putrescine and cadaverine in herring also
increased rapidly after 8 days of storage at 2-5°C. Histamine
levels remained low (<5.0 ppm), even after 12 days of storage. Prefreezing
of the herring prior to storage at chill temperatures may
have delayed the formation of histamine. The levels of putrescine,
cadaverine, histamine, TMA and TVN were lower in the press cake
meals than in the raw material, which was possibly due to amine
losses in the press liquor and thermal degradation of amines.
Elevation of processing temperature from 75°C to 100°C had little
effect on spoilage indicator levels but did increase the amount of
press liquor released from the raw materials. Progressive spoilage
of the raw materials also increased the yields of press liquor and
concomitantly decreased the yields of fish meal. The levels of TVN,
TMA, putrescine, histamine and especially cadaverine were
considered to be useful in determining spoilage of the raw material
but only the less volatile amines (putrescine, cadaverine and
histamine) may prove useful in predicting the quality of fish meal.
Spoilage of the raw material, regardless of the protein
source, adversely affected apparent digestibility coefficients for
organic matter, gross energy and digestible energy content in
chinook salmon and rainbow trout. As spoilage of the raw material
increased, digestibility values decreased. Protein digestibility
values were least affected by the degree of spoilage. Since fish
meals contain high levels of protein and lipid but almost no
carbohydrate, the probable cause of reduced organic matter
digestibility of spoiled protein sources was depression of lipid
availability. Elevation of processing temperature did not adversely
affect digestibility values in either species.
Differences in digestibility values were noted between species
for meals produced from highly spoiled raw material and freezedried
material. Rainbow trout seem to be more sensitive than
chinook salmon to spoilage of the raw material as digestibility
values of the meals produced from spoiled raw material were more
severly depressed in rainbow trout. Lipid oxidation may have
accounted for these differences, as chinook salmon recently
transferred to sea water may be susceptible to quality of dietary
lipids.
Ocean perch hydrolyzates were highly digestible in both
chinook salmon and rainbow trout. Pepsin solubility was greater
than 98% regardless of processing and spoilage conditions. The pHstat
values (utilizing enzymes extracted from rainbow trout),
increased as spoilage of the raw material progressed but were
slightly reduced in the high temperature meals. The pepsin
solubility values also increased as spoilage of the herring protein
sources progressed.
TVN and TMA showed little promise as methods for predicting
the nutritive value of ocean perch hydrolyzates or herring fish
meals, although monitoring TVN and TMA levels in the raw material
is recommended. However, the relationship between levels of
putrescine, cadaverine and histamine may prove useful in
determining the quality of fish meal.
In conclusion, advanced spoilage of raw material (> 8 days for
herring and ocean perch stored at 2-5°C) before processing resulted
in depressed digestibility values in both rainbow trout and chinook
salmon.
|
Extent |
8752512 bytes
|
Genre | |
Type | |
File Format |
application/pdf
|
Language |
eng
|
Date Available |
2008-12-16
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0086533
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
1992-11
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.