The effect of brine- and plate-freezing and length of subsequent frozen storage upon flesh pH, thaw drip, color, flavor, TBA (2-thiobarbituric acid) values, and long chain free fatty acids of Pacific halibut, Chinook and Coho salmon was determined. The effect of freezing method upon sodium, potassium, and chloride concentration was also determined. Flesh pH of all three species generally declined significantly (P ≤ 0.05) with length of storage. The thaw drip of Pacific halibut and Chinook salmon was less for the brine- than the plate-frozen samples after storage for 9 to 31 weeks whereas subsequently the brine-frozen samples had approximately equal or greater thaw drip than the plate-frozen. The thaw drip of all samples, except those from plate-frozen halibut, tended to increase with length of storage. The Hunter 'a' and a/b values of Chinook and Coho salmon generally increased during storage. The difference in flavor between brine- and plate-frozen outside muscle of halibut and Chinook salmon reached a maximum at 31 and 26 weeks of storage respectively, and then steadily decreased. In contrast, the difference in flavor between brine- and plate-frozen Coho salmon outside muscle steadily increased during storage. The difference in flavor between brine- and plate-frozen inside muscle of all species, except for the Coho salmon at 10 weeks and halibut at 31, 62 and 81 weeks of storage, was not significant. The difference in TBA values (an index of oxidative rancidity) between brine- and plate-frozen outside muscle samples rapidly increased and reached a maximum at 45, 26, or 27 weeks (the brine-frozen samples having the higher values) then decreased until there was approximately no difference at 81, 77 and 78 weeks of storage for halibut, Chinook and Coho salmon, respectively. Method of freezing or length of storage had little effect on the TBA values of inside muscle for all species. Method of freezing had little effect on the concentration of individual free fatty acids (percentage of total free fatty acids analyzed). The concentrations of several free fatty acids was affected by length of storage but the pattern of change during storage was erratic. Freezing method had an effect on the concentration of some individual free fatty acids (μ.g per gram of neutral lipid) of halibut and Chinook salmon but not of Coho salmon. In general, with all species, the concentration of the individual free fatty acids was greatest in the inside muscle. Also for halibut and Chinook salmon, particularly where there was a significant difference among storage times, the concentration of the free fatty acids rapidly increased during the first 26 to 31 weeks of storage. Method of freezing and length of frozen storage had a significant effect on total free fatty acids analyzed for only Chinook salmon. Total free fatty acids significantly (P ≤ 0.05) differed between inside and outside muscle of halibut and Chinook salmon but not of Coho salmon. The effect of method of freezing upon potassium concentration was small and varied with species. The effect of brine-freezing upon most variables measured was either small and/or complex. For all three species the sodium and chloride concentration was two to three times greater in the brine-frozen outside muscle than in all other samples. The taste panel results and the TBA values indicate that brine-freezing does impair the quality of the outside muscle of halibut and Chinook salmon during the early stages of frozen storage. / Land and Food Systems, Faculty of / Graduate

Myofibrillar proteins, the main components that impart functional properties to muscle foods, can undergo denaturation and aggregation during frozen storage. The overall objective of this research was to study the changes in protein structure that are associated with the preparation and frozen storage of surimi. In addition, the relative cryoprotective effects of whey protein concentrate, whey protein isolate, soy protein isolate, flaxseed meal and flaxseed protein were assessed in surimi during storage. / Raw surimi was prepared by repeatedly washing Alaska pollock flesh with chilled water. The product was either slowly frozen or underwent rapid freezing using liquid air; in either case it was then subjected to frozen storage at -20°C for 24 months. Protein structural changes were monitored using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), native-PAGE, Fourier transform infrared/attenuated total reflectance (FTIR/ATR) spectroscopy, and differential scanning calorimetry (DSC). / FTIR/ATR spectroscopy showed that during preparation of surimi the alpha-helix content increased with increased number of washing cycles. DSC results revealed a shift in the thermal transition of actin to a higher temperature during surimi preparation. All electrophoresis, FTIR/ATR spectroscopy and DSC results revealed a loss of myofibrillar proteins from surimi after three washing cycles, suggesting that three washing cycles were adequate to prepare surimi. / Native-PAGE showed no major changes in surimi after 24 months storage at -20°C. SDS-PAGE showed relatively minor changes in protein subunit structure with some loss of the myosin light chains (MLC); myosin heavy chain (MHC), actin and tropomyosin were found to be relatively stable. FTIR/ATR spectroscopy indicated a significant decrease in alpha-helix relative to beta-sheet structure in surimi after 2 years of storage at -20°C. The loss of alpha-helical content was more significant in slowly frozen surimi compared to rapid-frozen surimi samples. DSC results revealed a shift in the thermal transition of actin to lower temperatures during frozen storage of surimi. / Changes in the ratio of alpha-helix to beta-sheet structures suggested that flaxseed protein was the most effective cryoprotectant, followed by whey protein isolate and soy protein isolate, for maintaining protein structure stability during frozen storage. Whey protein concentrate and flaxseed meal showed the least cryoprotective ability. After 15 days storage at 4°C, the SDS-PAGE results showed that flaxseed protein was the only cryoprotectant that prevented the degradation of myosin heavy chain, actin and myosin light chains.

Graduation date: 1950

Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 28-33).

No description available.

The storage life at 43°F of ground dover sole fillets (Microstomas pacificus) was determined microbiologically after treatment with ionizing radiation and antimicrobial agents. Sodium benzoate, potassium sorbate and the sodium salts of the methyl and propyl esters of parahydroxybenzoic acid (MPB and PPB) all approximately doubled the refrigerated storage life of irradiated dover sole. The dose levels employed were 0.1, 0.3, and 0.5 Mrad. The concentration of the agents used in each case was 0.1 percent. The normal spoilage of dover sole is caused predominately by the outgrowth of pseudomonads. After irradiation, however, the spoilage is due to the outgrowth of Achromobacter and certain Gram positive organisms. The spoilage pattern was not changed by the antimicrobial agents tested except at the higher dose level (0.5 Mrad), at which the spoilage was caused by yeasts. The additives had no effect on the growth rate of the microorganisms of dover sole. They merely prolonged the length of microbial dormancy that followed radiation exposure. Possible mechanisms involved in the combined effect of antimicrobial agents and irradiation are discussed. / Graduation date: 1965

Graduation date: 1951

No description available.

Graduation date: 1953

No description available.