100-5 |
Cryoprotection of frozen rainbow trout, Oncorhynchus mykiss, fillets for smoked trout production |
S. JITTINANDANA, P. B. Kenney, S. D. Slider, and R. A. Kiser. Dept. of Animal & Veterinary Sciences, West Virginia Univ., Agricultural Sciences Bldg., PO Box 6108, Morgantown, WV 26506-6108 Deterioration in food quality results from biochemical, enzymatic and functional changes in proteins during freezing and frozen storage. Using cryoprotectants in frozen fillets would improve texture development, processing yields, and quality of smoked fish products produced from these frozen fillets. This study was conducted to determine if sucrose/sorbitol or sodium lactate, alone or with phosphates or magnesium chloride would preserve quality of frozen trout fillets that were subsequently used for smoked trout production. Fillets were soaked in 8.0% (w/v) sucrose/sorbitol (1:1 w/w) or 1.0% (w/v) sodium lactate, alone or in combination with 0.5% (w/v) sodium tripolyphosphate/tetrasodium pyrophosphate (1:1 w/w) and 0.05% (w/v) magnesium chloride for 90 min. The experimental design was a 3x2x2 factorial, randomized incomplete design with three replications. Water was used as a control. Smoked fillets and trout mince were prepared, and muscle color, raw and cooked pH, brine uptake, cook yield, shear force, salt content, water-phase salt content, and proximate composition were measured. Mince was used for texture (hardness and cohesiveness) evaluations. All responses were determined at 0 and 90-d frozen storage. L*, a*, and b* values of intact fillets, treated with cryoprotectants and stored for 90 days at –20°C, were lower than untreated fillets prior to freezing (P<0.05). Sucrose/sorbitol and sodium lactate increased (P<0.05) gel hardness and cohesiveness, cook yield, pH and fat content of smoked products compared to an opposite effect for water after frozen storage. A greater increase in cook yield and cooked moisture content was effected by sucrose/sorbitol than by sodium lactate (P<0.05). Phosphates increased (P<0.05) pH of fillets after soaking that in turn decreased L* value (P<0.10) and increased b* value and cooked pH (P<0.10). Magnesium chloride enhanced (P<0.05) the increase in cooked pH caused by frozen storage. Frozen storage increased (P<0.05) salt content, water-phase salt content, raw and cooked ash, and decreased (P<0.05) brine uptake and fillet shear force. Cryoprotectants minimized negative effects of frozen storage on intact fillets.
Session 100, Seafood Technology: Texture, Chemistry
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