ON THE PROTEIN DENATURATION OF FREEZE-DEHYDRATED FISH MUSCLE

The protein denaturation of separated white and bloody muscle of jack mackerel (Trachurus japonicus) during the freeze-dehydrating and the subsequent storage (30°C) was studied by following the extractability of muscle protein with 0.6M KCl and the change of salting-out curves, and compared with those of the “whole flesh” (white and bloody muscle not separated from each other) freeze-dehydrated at the same time. The results obtained are as follows: 1) Amounts of extracted myosin decreased remarkably during the freezing and at the end of freeze-dehydrating, but this severe denaturation of protein was regarded by authors as exceptional results owing to the faltiness of experimental conditions. 2) Through freeze-dehydrating process the amounts of the so-called albumin fraction decreased in the bloody muscle and the “whole flesh”, but they remained almost unchanged in the white muscle. 3) The salting-out curves of the extractable myosin with 0.6M KCI suggested that the components of myosin fraction were different among these three kinds of muscles, and salting-out patterns of each muscle changed conspicuously during the experimental period. 4) The rapid denaturation of protein was observed on the first day of the storage at 30°C.