Polyphosphate Treatment of Frozen Cod. 2. Effect on Drip, Yield, Lipid Hydrolysis and Protein Extractability in Twice-Frozen Newfoundland Summer Trap and Fall Cod

• Published in: Journal of the Fisheries Research Board of Canada
• Main Authors: MacCallum, W. A., Shieh, H. S., Chalker, Dorothy A., Dyer, W. J., Idler, D. R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1964
• Subjects: General Medicine; Gadus morhua; Newfoundland
• Online Access: http://dx.doi.org/10.1139/f64-044; http://www.nrcresearchpress.com/doi/pdf/10.1139/f64-044

Thaw-drip from once-frozen fall-caught Newfoundland cod (Gadus morhua L.), thawed after storage at −23 °C for up to [Formula: see text] weeks, was equal to total drip from twice-frozen fish treated with sodium tripolyphosphate between freezings. Treatment of twice-frozen cod before the first freezing only had no effect on reducing total thaw-drip below that from twice-frozen untreated samples and the yield, although higher in the former than in the latter, was no better than that from once-frozen untreated fillets. Yields from twice-frozen fish were improved greatly by dipping prior to the second freezing and by dipping before each freezing. Treatment between freezings gave yields close to 100% of initial fillet weight whereas losses with the untreated once- and twice-frozen product appear close to 7 and 15%, respectively.With summer-caught trap fish, characterized by higher thaw-drip values which were not affected by treatment, yields of twice-frozen cod were improved; however, losses were still about 12% in fish treated between freezings.Treatment of twice-frozen cod from the two sources did not appreciably affect lipid hydrolysis or protein denaturation. However, lipid content and free fatty acid production were significantly higher in the trap fish samples as compared to the fall-caught cod.