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Frozen stabilized mince, its production, and thermophysical propertiesSimpson-Rivera, Ricardo Jose 11 March 1993 (has links)
Graduation date: 1993
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The relationships between fluctuations in oceanographic conditions, forage fishes, predatory fishes, predator food habits, and juvenile salmonid marine survival off the Columbia River /Emmett, Robert L. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 284-312). Also available on the World Wide Web.
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Utilization of wastes from Pacific whiting surimi manufacturing : proteinases and protein hydrolysateBenjakul, Soottawat 17 April 1997 (has links)
Both liquid and solid wastes from Pacific whiting surimi manufacturing were
characterized and value-added products were recovered. A proteinase in surimi wash
water (SWW) was determined to be cathepsin L with Mr 54,200 on SDS-substrate gel.
Heat treatment and acidification shifted the activity zone to M [subscript r] 39,500. No evidence of
calpain, cathepsin B or H activity was found. Cathepsin L from SWW was recovered
by ohmic heating (55°C for 3 min), ultrafiltration, and freeze-drying with overall yield
of 0.83 g protein/L SWW and 78% recovery of activity. A 5.9 purification fold was
achieved by these processes. The recovered enzyme had an optimum activity at pH 4.0
and showed preferable hydrolytic activity towards casein, acid-denatured hemoglobin and
myofibrils. β-Mercaptoethanol, dithiothreitol and urea enhanced the enzyme
activity. The recovered proteinase showed 18.5% residual activity after
7 wk storage at 4°C.
Proteolytic activity in solid waste and digestive organs from Pacific whiting was
investigated. Pepsin-like proteinase predominated in solid waste, while trypsin-like
proteinase was predominant in viscera. Carboxypeptidase b was found in both viscera
and solid waste.
Protein hydrolysate was produced from Pacific whiting solid waste (PWSW) using
commercial proteinase, Alcalase, under optimum hydrolysis conditions. Enzyme
concentration, reaction time and waste/buffer ratio affected the hydrolysis and nitrogen
recovery (NR). Correlation between the degree of hydrolysis (DH) and NR was high
(R₂=0.978). Freeze-dried hydrolysate contained 79.97% protein and showed similar
amino acid composition to PWSW and Pacific whiting muscle but tryptophan was
reduced. With different DH (20, 30, 40, 50, 60%), surface hydrophobicity, total and
surface sulfhydryl content decreased as the DH increased. The hydrolysate showed a
high solubility over a wide pH range. Fat adsorption and fat binding capacity were
reduced, while foam expansion was enhanced with an increased DH. Hydrolysate with
DH of 30% showed highest emulsifying activity. Low emulsion stability and high foam
stability were obtained in all hydrolysates tested. Hydrolysate showed antioxidant
activity, but no obvious differences in activity were found with varying DH and
hydrolysate concentrations. / Graduation date: 1997
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Electrical and thermal properties of Pacific whiting surimi paste and stabilized mince in multi-frequency ohmic heatingWu, Han 18 March 1997 (has links)
Graduation date: 1997
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Determination of quality parameters for the Pacific whiting fishery using neural network and induction modelingPeters, Gregory J. 08 December 1995 (has links)
Pacific whiting, with a maximum sustainable yield between 150,000 and
250,000 metric tons, is the largest stock of fish found off Oregon. The majority of the
fish are processed into surimi. Hundreds of variables could potentially affect surimi
quality (gel strength). Alternative harvesting and processing input combinations, as
well as product quality attributes and their influences, were collected for the 1992-94
Pacific whiting seasons. This data was combined with other research on Pacific
whiting quality to develop a comprehensive model of the Pacific whiting fishery.
Neural network and induction modeling methods were used to isolate the importance
of each input variable and document its interactive effects on other variables. Neural
network modeling does not have the limitations of standard modeling techniques. A
neural network model can "learn" and adjust weights among inputs and interactions as
situations change. This allows for development of models which assign weights to all
inputs, yet is easily maintained and updated.
Another modeling method, known as induction, divides the information into
smaller, more defined, subgroups which are analyzed separately using regression. This
strategy reduces complications due to discontinuities in the data. A hybrid model was
developed by combining results of the two modeling methods.
These methods were compared to multiple regression for their effectiveness in
prediction. The hybrid model provided the most accurate predictions (96% of
predictions within 10% of actual value), followed by neural networks (92%), induction
(84%), and regression (74%).
Of the 88 variables examined, only ten and their interactions were significantly
related to final product quality. These variables include the time it takes to process
the fish from capture, the temperature the fish are stored until processing, the salinity,
moisture content, and pH of the fish, the length and weight of the fish, the date and
place where the fish were captured, and the water:meat wash ratio of the various
surimi washes during processing. Most of the variables were highly interactive and
nonlinear.
The information derived from these models can be used to optimize production
decisions and maximize profit. Quality influences of Pacific whiting are crucial for
long term production and can be used to benefit the entire industry. / Graduation date: 1996
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Characterization of biochemical, functional properties, and market potential of Pacific whiting fish sauceTungkawachara, Somjintana 19 September 2003 (has links)
Biochemical properties, functional properties, and market potential of
Pacific whiting (PW) fish sauce were investigated. Biochemical properties of fish
sauce made from whole fish (W) and a mixture (1:1) of whole fish and surimi
byproducts (WB) were compared. Market potential was evaluated through phone
interviews and consumer panelists. Proteolysis was primarily affected by cathepsin B-like
and L-like enzymes. Acidic pH (4-5) with low salt concentration (15-20%)
provided a greater degree of hydrolysis (DH), total nitrogen, and amino nitrogen
content in PW fish sauce compared to the traditional process. The greatest
Angiotensin Converting Enzyme (ACE) inhibition (96.8%) was found in samples
fermented with 15% salt at pH 5.0 for 30 days. Anti-oxidative activity (AT) increased
when fermentation continued and depended on fermentation pH. Peptides with MW
<590 Da possibly played an important role in ACE inhibition. Consumer tests
disclosed no significant difference in flavor liking and overall liking among fish sauce
samples (W, WB, and commercial anchovy fish sauce). / Graduation date: 2004
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The effects of harvesting Pacific hake (Merluccius productus) on the offshore community : the results of a multi-species modelGartz, Russell G. 05 December 1994 (has links)
The effects of harvesting Pacific hake (Merluccius productus)
were examined with a multi-species numerical model composed of
seven logistic growth equations coupled by a food web. The
food web was composed of: California sea lions (Zalophus
californianus), hake, sablefish (Anaplopoma fimbria), spiny
dogfish (Squalus acanthias), a generic rockfish species
(Sebastes spp.), Northern anchovy (Engraulis mordax), and a
generic euphausiid species (as an example, Pacific krill,
Euphausia pacifica). The model was tuned to mimic stock
assessment biomass estimates for the years 1980 to 1991, after
which a short term experiment and a sensitivity analysis were
conducted. The short term experiment used a factorial design,
with hake fishing and fishing for rockfish, sablefish, and
anchovy as treatments. It was analyzed with scale analysis
techniques. The results indicate that hake (from a management
viewpoint) is potentially most important in the offshore
community as a prey item for sea lions and as a predator on
anchovies, but hake fishing mortality had a small effect on
either population during the time span of the experiment.
Results also suggest that hake has little or no competitive
interaction with other species that are trophically similar.
Increased harvesting of hake would probably do little to
increase the biomass of rockfish or sablefish. The general
conclusion of both the sensitivity analysis and the experiment
is that species below their carrying capacity are mostly
affected by changes in growth and removal processes while
species close to their carrying capacity are mostly affected
by processes controlling prey availability.
A forty year projection from 1991 to 2031 was conducted
to examine the effects of hake fishing on sea lion and anchovy
biomass. Results indicate that sea lion biomass will vary
inversely with hake fishing effort, while anchovy biomass is
directly proportional to hake fishing effort. Results also
indicate that hake experience environmental conditions not
favorable to recruitment. During favorable conditions the hake
population builds up a "surplus" that carries it through
periods of unfavorable conditions. Increased hake fishing
effort reduces the response of the population to favorable
conditions. The results of this research constitute a step
from the theory toward the practice of proactive multi-species
and ecosystem management. / Graduation date: 1995
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