published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

The effects of ambient temperature storage on the chemical and nutritional characteristics of phosphoric and sorbic acid-stabilized fish autolysates were determined. Variations in sample composition due to autolysis, deboning, and acidification were also evaluated. Autolysates of English sole (Parophrys vetulus), true cod (Gadus macrocephalus), Dover sole (Microstomus pacificus), and orange rockfish (Sebastodes pinniger) carcass wastes, whole Pacific hake (Merluccius productus) and dogfish shark (Squalis acanthias), and a hake/tuna viscera (70/30 wt/wt) mixture were utilized in the investigation. Samples were acidified to ca. pH 3.25 with phosphoric acid (85% w/v) and contained potassium sorbate at the 0.2% (wt/wt) level. Screen separation of bone reduced the ash levels of samples, with the exception of dogfish shark. Loss of bone minerals, specifically calcium and phosphorus, was responsible. Phosphoric acid addition elevated ash and phosphorus contents to higher levels than for raw materials. Acid-stabilized autolysates were stable to microbial outgrowth throughout 8 months of ambient temperature storage. Slight increases in pH levels were generally observed. Sorbate levels decreased at an apparently exponential rate with respect to time (r=-.9146, P [greater than or equal to] .005). Hydrolytic rancidity did not proceed during storage. Stability towards microbial outgrowth, inactivation of endogenous lipases during pasteurization, and maintenance of acidic environmental conditions enhanced fat stability. Oxidative rancidity, as measured by 2-thiobarbituric acid (TBA) numbers, progressed during storage. Carcass wastes showed higher rates and overall levels of oxidation. Initial free fatty acid levels correlated in a linear manner with 0 and 4 month TBA numbers (r=.9548, P [greater than or equal to] .005; r=.9187, P [greater than or equal to] .005, respectively). The regression of TBA numbers at 4 months on zero time values increased in a linear manner (r=.9346, P [greater than or equal to] .005). Proteolysis during storage, as monitored by free amino groups, was not detected. Inactivation of native proteases during processing and the microbial stability of samples were responsible. Levels of available e-amino lysine and tryptophan were stable throughout storage. The protein quality of acidified hake, dogfish shark, orange rockfish, and English sole autolysates, stored for 0, 4, and 8 months, was evaluated using protein efficiency ratio (PER) determinations. Protein quality was not affected by storage in samples of acidified hake, English sole, and orange rockfish (P=.05). Ratios for all samples of hake and the 0 and 8 month samples of dogfish shark did not vary significantly (P=.05) from the casein control. English sole and orange rockfish samples yielded PER values that were inferior to casein and round fish samples (P=.05). The regression of feed consumption and PER values on TBA numbers decreased in a linear manner (r=-.7999, P [greater than or equal to] .005; r=-.8424, P [greater than or equal to] .005, respectively). Higher contents of nutritionally inferior visceral proteins and increased rates of oxidative rancidity in the carcass waste samples probably were responsible for their reduced protein qualities. / Graduation date: 1978

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In processing lobster, approximately 70% of the body weight is discarded as waste. The solid waste consists of shell, viscera and a small amount of meat. Lobster waste is an excellent source of protein (26.6%) crude fat (2.7%) and pigment (98 $ mu$g/g) on a dry weight basis which could be processed into a stable complex known as carotenoprotein. / Procedures for extraction of carotenoprotein from lobster waste have been developed, along with investigation of its distinctive physicochemical properties. The main factors were: demineralization agents (EDTA, HCl or heat) and precipitation agents ((NH$ sb4$)$ sb2$SO$ sb4$ or HCl). Lobster carotenoprotein recovered under different extraction procedures showed significant differences in terms of quantity and quality of the product recovered. However the procedures did not appear to affect the physical properties and amino acid profiles of carotenoprotein. / Optimal recovery involved treatment with EDTA as demineralization agent and precipitation with (NH$ sb4$)$ sb2$SO$ sb4$. Proximate and amino acid analyses indicated the potential of the recovered lyophilized protein as feed ingredient for cultured salmonids.

Lobster waste (including the head and hard carapace, viscera, mandibles and gills) contains approximately 98 $ mu$g/g total astaxanthin, 23% protein, 20% chitin, 34% ash, and 2.2% crude fat on dry weight basis. Carotenoprotein, amounting to 16% of the dry matter was effectively recovered from lobster waste by a trypsin aided process. Air-dried carotenoproteins were enriched in protein by about 108-115%, in crude fat by 540-594% and in carotenoid pigment by about 147-329% as compared with the waste material. Furthermore, the ash and chitin levels in the products were considerably lower than those of the raw material. / Drying characteristics of carotenoprotein was evaluated in a modified air-drier using air temperature (45$ sp circ$C, 55$ sp circ$C or 65$ sp circ$C) and relative humidity (5% and 15%) as main factors. The study indicated that higher temperatures achieved faster drying rates of the product but adversely affected its nutritional composition and/or quality. The proximate compositions of carotenoprotein dried at 45$ sp circ$C and relative humidity of 5% or 15% were comparable with that obtained by freeze drying. / Thus, the process achieved a substantial reduction in the levels of anti-nutrients associated with lobster waste (i.e., ash and chitin) while elevating the levels of carotenoid pigments and essential nutrients such as protein and fat in the recovered product. These characteristics of the tray-dried carotenoprotein suggest that it could be used as an inexpensive source of pigment and protein in diets of cultured salmonid species.

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Shrimp waste samples were extracted with a variety of organic solvents. Each fraction was measured for antioxidant activity by determining the rate of oxidation of β-carotene-linoleic acid in an emulsion system. An ethanol extract exhibited the highest antioxidant activity. Purification of the most active fraction was accomplished by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Antioxidant activity was not significantly effected by heating at 100°C for 4 hr or 30 days storage at 4°C. Purified antioxidant samples were further analyzed by several spectroscopy methods such as Fourier transformed-infrared spectroscopy (FT-IR), mass spectrometry and nuclear magnetic resonance (NMR). The antioxidant was characterized as an ortho-disubstituted benzene. The content of antioxidant in shrimp waste was estimated to be 1.80 ppm. Antioxidant from shrimp waste was extracted and partially purified by silica gel glass column chromatography. Two species of rockfish (Sebastolobus alascanus, Sebastes ruberriumus) were treated with crude antioxidant solution respectively, while rockfish fillets (Sebastes alutus) were treated with different concentrations of antioxidant solutions from the column chromatography. Higher a* values were found in rockfish samples treated with antioxidants compared to the control without antioxidant during iced storage. Furthermore, rockfish fillets treated with 0.20%, and 0.50% (w/v) antioxidant had lower 2-thiobarbituric acid (TBA) values compared to the control group of rockfish fillets (Sebastes alutus). Crude extract (0.50% w/w), and purified antioxidant (0.10%, 0.20%, and 0.50% w/w) from shrimp waste were applied to sablefish mince and evaluated for their effectiveness to inhibit oxidative and hydrolytic rancidity of mince samples. Treatments with crude extract (0.5%), partially purified antioxidant (0.2%, 0.5%) had a significantly lower TBA, and peroxide value (PV) compared to the control group during refrigerated (4°C) and frozen storage (-20°C). The results from free fatty acid values suggested that antioxidant from shrimp waste had no effect on hydrolytic rancidity in sablefish mince. / Graduation date: 1995

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The activity of the tryptic enzymes occurring in the pyloric caeca of several salmons has been measured with respect to the effects of pH, ammonium chloride concentration and temperature on the enzyme bate material prepared from it. Several defferent methods of preparing a commercial bate have been investigated. From these data, an economic estimate of the feasibility of the production of leather bates from salmon pyloric caeca has been made. A sample of bate has been submitted for commercial testing. / Science, Faculty of / Zoology, Department of / Graduate