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Roles of TMAOase in muscle and drips of Alaska pollock fillets at various freeze/thaw cycles
Author(s) -
Lee Jinhwan,
Park Jae W.
Publication year - 2018
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/jfpp.13427
Subject(s) - trimethylamine , chemistry , food science , dimethylamine , haddock , fish <actinopterygii> , fishery , biochemistry , biology
Abstract Whole pollock quickly frozen at the Bering Sea were thawed: whole fish (WF) and headed/gutted fish (HF). Each treatment was filleted after 0, 12, 24, and 72 hr of refrigeration. Chemical analyses in fillets and drips at different freezing/thawing (F/T) cycles were conducted. Trimethylamine‐ N ‐oxide demethylase (TMAOase) activity, formaldehyde (FA), and dimethylamine contents were significantly higher in HF as the number of F/T cycles increased. FA in fillets and drips were significantly reduced at 12‐F/T, which indicated that FA was possibly linked to protein denaturation and textural toughness. Drastically increased trimethylamine and pH of HF72h at 1‐F/T might have been caused by endogenous microorganisms or enzymes. F/T, which is often used to mimic long‐term frozen storage, likely induced the rapid release of FA through the maximization of ice crystals followed by the accumulation of TMAOase. Practical applications Headed and gutted Alaska pollock before filleting and subsequent freezing was found to be more sensitive to TMAOase activity than whole fish, easily leading to textural toughening as higher shear force values were observed. However, when fillets made from whole fish after long refrigeration were subjected to 12 freeze/thaw cycles, textural toughness was also observed. Therefore, it is suggested that Alaska pollock whole fish should be filleted and frozen within 3 days of postharvest if fillets are to be stored frozen for longer periods (i.e., 2 years).