The polysaccharides from porphyra yezoensis suppress the denaturation of bighead carp myofibrillar protein

In this study, investigated was the effect of the porphyra yezoensis polysaccharides (PPs) on the denaturation of bighead carp (Aristichthys nobilis) myofibrillar protein (MI) during frozen storage at -18 degrees C for 90 d. The PPs (2.5%, 5%, and 7.5%, respectively) was added to 100 g of Mf. The changes in the Caadenylpyrophosphatase (ATPase) activity and unfrozen water content in Mf were examined to evaluate he denaturation of Mf during frozen storage. Ca-ATPase activity decreased gradually during frozen storage at -18 degrees C upon addition of PPs. By contrast, Ca-ATPase activity in the control group dropped drastically during the first 45 d of storage and then further decreased gradually for up to 90 d of storage, indicating a biphasic denaturation pattern. PPs addition significantly increased sulfhydryl contents in the Mf of the treatment groups compared with that of the control group (p < 0.05) during frozen storage at -18 degrees C. (C) 2014 Elsevier B.V. All rights reserved.