Effect of chitooligosaccharides on the denaturation of weever myofibrillar protein during frozen storage

We investigated the effect of chitooligosaccharides on the denaturation of weever (Lateolabrax japonicus) myofibrillar protein during frozen storage at −18 °C for 90 days. Chitooligosaccharides (2.5–10 g dry weight) were added to 100 g of myofibrillar protein, and the changes in the Ca-adenylpyrophosphatase (ATPase) activity, unfrozen water content, solubility, and sulfhydryl content of the myofibrillar protein were examined during frozen storage. We observed that the Ca-ATPase activity and solubility of the myofibrillar protein decreased gradually during frozen storage at −18 °C following the addition of chitooligosaccharides. In contrast, the Ca-ATPase activity and solubility of the myofibrillar protein of the control group decreased markedly during the first 45 days of storage and then further decreased gradually for up to 90 days of storage, indicating a biphasic denaturation pattern. The addition of chitooligosaccharides resulted in a significant increase in unfrozen water and sulfhydryl contents of the myofibrillar protein of the treatment group compared with that of the control group (p < 0.05) during frozen storage at −18 °C.