Studies on the Quality of Newfoundland Cod.: 11. Thaw-Drip in Polyphosphate-Treated and Untreated Fillets

• Published in: Journal of the Fisheries Research Board of Canada
• Main Authors: Chalker, Dorothy A., MacCallum, W. A., Idler, D. R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1965
• Subjects: General Medicine; Gadus morhua; Newfoundland
• Online Access: http://dx.doi.org/10.1139/f65-069; http://www.nrcresearchpress.com/doi/pdf/10.1139/f65-069

Two laboratory methods used to determine thaw-drip were compared: a still-air defrost method in which samples are thawed at 3–5 °C so as to permit no contact between the drip and the fish, and a water-immersion method in which samples are thawed in a plastic bag at 20–21 °C. Using pre-rigor frozen, paired fillets of Newfoundland trap-caught cod (Gadus morhua), it was shown that it is feasible to use the air-defrost method to compare the amount of thaw-drip from polyphosphate-treated and untreated fillets.The still-air defrost method using weight determinations gave a truer absolute value of thaw-drip. Both methods showed that polyphosphate treatment reduced thaw-drip but the water-immersion method showed a greater percentage reduction in thaw-drip as a result of treatment.The work clarifies a point concerning the variability of uptake of polyphosphate and the difficulty in getting reproducible results even using paired fillets. This points up a serious limitation to its commercial application and throws serious doubt on the use of large numbers of fish as a statistical approach to the assessment of the effect of polyphosphate.