Browsing UAF Graduate School by Subject "Preservation"
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Biochemical and microbiological assessments of dried Alaska pink salmon, red salmon and Pacific cod headsFish heads are generally considered as unsuitable byproducts for human consumption in the United States. The initial objective was to compare the moisture content and water activity levels on dried pink salmon (Oncorhynchus gorbuscha) and dried red salmon (O. nerka) using different temperature and time integration. The secondary objective was to compare shelf life characteristics, rancidity and mold growth, between dried pink dried salmon and dried Pacific cod (Gadus macrocephalus) heads stored for up to 180 days at the ambient temperature (21°C) for East African seafood markets. The third objective was to assess the antioxidant effects for frozen and dried pink salmon heads stored for up to 60 days. In a preliminary experiment, dried red salmon heads were found unsuitable due to the water activity levels above 0.6. The critical moisture contents were detected around 10% for pink salmon heads and were around 15% for Pacific cod heads to reduce water activity levels below 0.6 in these products. The applicable drying temperatures of 50°C lasting over 50 hours for pink salmon heads and 50°C for over 24 hours followed by 30°C for over 24 hours for Pacific cod heads were found optimal. Dried Pacific cod heads showed shelf stability as a potential dried seafood product. Frozen pink salmon heads had 60 days shelf life, while heads with antioxidant glazing retarded oxidation levels (p <0.05). The antioxidant treatment in dried pink salmon heads kept oxidation levels lower than the acceptable limit up to 60 days. This study provided essential information to improve the utilization of these Alaskan seafood byproducts.
The effects of freezing and storage time on the quality of reindeer meatRestaurants, wholesalers and retailers of fresh meat require a year round consistent supply of uniform quality product to sustain demand and justify niche market costs such as advertisement and stocking product. Frozen reindeer meat could be stored, short or long term to increase availability provided there are no adverse effects of freezing. No studies to date have evaluated the effects of freezing and storage time on reindeer meat quality. Nine reindeer steers (castrated bulls; age 2.5 years) were fed a balanced milled ration at the University of Alaska Fairbanks (UAF) Reindeer Research Program (RRP) facility at the Agricultural Forestry Experiment Station (AFES). In February, animals were transported to a USDA approved meat processing facility for slaughter where both striploins (M. longissimus dorsi) were removed from the carcasses. The striploin samples were allocated to four subsamples consisting of fresh (control), freshly frozen, 6 month frozen and 12 month frozen treatment groups to determine if freezing and frozen storage of reindeer meat for up to one year effects meat quality. All samples underwent shear force measurement, water holding capacity (WHC) determination, proximate analysis, sensory evaluation, TBARS (rancidity) and fatty acid methyl ester profile (FAMES) analysis. Meat was sampled after 6 months of frozen storage for amino acid and mineral analysis. Shear force values were not significantly different amongst treatment groups fresh to 12 month (P=0.992). Purge and cooking loss variation were significant between fresh and 12 months (P = 1e-05,1e-04). There was no significant difference from fresh to 12 month in moisture, ash and protein content while lipid content variation was significantly different (P = 0.99, 1.00, 1.00 and < 1e -6 respectively). Tenderness and juiciness attributes were not significantly different among treatment groups fresh and 12 month (P=0.91 and P=0.53); however, an off flavor attribute was significantly different (P=0.005) amongst treatment groups suggesting that off flavor diminishes with freezing. While not detected in sensory evaluation, mean TBARS (rancidity) values increased significantly (P = <.1e-04) between fresh and 12 months. Characterization of reindeer muscle indicated that the amino acid profile and selected mineral were consistent with that of a high quality nutritional meat product. Omega 3 fatty acid (W3), Omega 6 fatty acid (W6), Monounsaturated fatty acid (MUFA), Polyunsaturated fatty acid (PUFA), the ratio between Omega 3 and Omega 6 (W3/W6) and the ratio between PUFA and MUFA (PS) were not significantly different while Saturated fatty acid (SAFA) was significantly different amongst treatments groups from fresh to 12 months. (P= 0.35, 1.00, 0.96, 0.12, 1.00, 0.14 and 0.03). Results of this study suggest reindeer meat can be frozen for up to a year without compromising quality. This could facilitate the marketing flexibility for the reindeer industry to be able to provide a consistent supply of product year round to niche restaurants and wholesalers while commanding a premium price.