Denaturation of Fish Muscle Proteins During Frozen Storage

Studies on the freeze denaturation of fish muscle proteins were reviewed with emphasis given to changes in their physico-chemical and biochemical properties during frozen storage. Denaturation of actomyosin commonly occurs during frozen storage and the side-to-side aggregation of myosin molecules appears to play a major role in this reaction. The author's group performed freezing studies with isolated preparations of proteins from fish muscle, i.e., actomyosin, myosin, H-meromyosin (HMM), L-meromyosin (LMM), and actin. Freeze denaturation occurred with individual proteins as well as with their subunits. Not only aggregation but also some conformational changes were observed. Denaturation was inhibited significantly in the presence of added monosodium glutamate (MSG). About 30 compounds were found to inhibit denaturation and their mechanisms of action are discussed.