Comparison of methods of differentiating between fresh and frozen–thawed fish or fillets

Abstract

Freezing is an efficient way of storing fish. Objectively though, it is very hard to determine whether a fish has been previously frozen. Following an appraisal of various methods, we selected a physical determination (torrymeter), a physiological examination (eye lens) and three enzymatic assays (a-glucosidase, b-N-acetylglucosaminidase and b-hydroxyacyl-CoA-dehydrogenase) and applied them to three species: plaice (Pleuronectes platessa), whiting (Merlangus merlangus) and mackerel (Scomber scombrus). We also compared the results obtained following slow and rapid freezing and investigated how spoilage affects the torrymeter measurements and a-glucosidase assay values. For whole fish the physical method using the torrymeter is a reliable indicator. For fish fillets we recommend the enzymatic method using the a-glucosidase assay, which should be accompanied by measurement of the freshness to avoid confusing a frozen-thawed fish and a fish in an advanced stage of spoilage. The values noted for fresh and thawed whiting and plaice indicated cut-off values of 0.15 for whiting and 0.5 for plaice, above which it can be asserted that the sample had been frozen.

Fluorescence spectroscopy and chemometrics in the food classification - a review

“…Fluorescence spectrometry was used to measure lipid oxidation products during frozen fish storage (Aubourg & Medina 1999;Duflos et al 2002).…”

Differentiation between fresh and frozen–thawed sea bass (Dicentrarchus labrax) fillets using two-dimensional gel electrophoresis

“…Exudates are extracts from flesh juice (Morel, 1979) obtained after centrifugation (Ayala et al, 2005;Duflos et al, 2002;Tironi et al, 2010). Briefly, sampling for both groups of fish involved taking a piece of white muscle tissue (1 cm 3 ) from the lateral-dorsal (epiaxial) muscle quadrant of each fish.…”

“…Only the dorsal white flesh of the fillets was used in this study. The preparation of fish exudates was based on soft solubilization of proteins (Duflos et al, 2002). Each stage of the protocol was performed at +4°C.…”

“…deep-frozen). There are several methods to differentiate between fresh and frozen-thawed fish (Duflos, Le Fur, Mulak, Becel, & Malle, 2002;Karoui, Thomas, & Dufour, 2006). Some methods are suitable for whole fish and skin-on fillets, but difficulties remain http://dx.doi.org/10.1016/j.foodchem.2014.12.065 0308-8146/Ó 2014 Elsevier Ltd. All rights reserved.…”

Quality Characteristics of Breast Meat during Post-mortem Storage of Chicken Meat

“…닭고기의 조리형태도 과거에는 통닭이 주로 이용되 었으나, 요즘에는 부분육의 유통량이 증가하는 추세다(Korea Institute for Animal Products Quality Evaluation, 2014b). 또한 닭고기의 소비형태가 부분육으로 전환됨에 따라 제품의 육색, 질감, 보수력 등 과거에는 문제되지 않았던 육질문제가 소 비자는 물론 가공업자에게까지 대두되고 있다 (Roberts, 2008 (Duflos et al, 2002;Lougovois et al, 2004;Jung et al, 2011) 차이가 없다고 하였으며, 본 연구 결과와 유사하였다.…”