Texture and pH in fish muscle related to ‘cell fragility’ measurements

Abstract
Summary: The cell fragility method relates the protein denaturation of cold‐stored fish to the optical density of a muscle homogenate. A high E1/2 cm value has been claimed to indicate a good quality frozen fish while a low one would indicate considerable cold‐storage deterioration. Three independent groups of workers have now shown that the initial optical density of a muscle homogenate may vary considerably. It appears to be correlated with the pH of the muscle, which in turn is related to the texture. It has been found that a fish with a high pH has a soft texture and gives a low cell fragility reading, while a high reading is given by fish with low pH, which have a firmer texture.At low temperatures denaturation of the muscle is slight during coldstorage, so that this pH effect may well predominate in determining the optical density of the homogenate. Thus, while the cell fragility technique is not invalidated as a research tool, it can give misleading information when used on commercial samples of unknown pH.