In this study, investigated was the effect of the porphyra yezoensis polysaccharides (PPs) on the denaturation
of bighead carp (Aristichthys nobilis) myofibrillar protein (Mf) during frozen storage at
−18 ◦C
for 90 d. The PPs (2.5%, 5%, and 7.5%, respectively) was added to 100 g of Mf. The changes in the Ca adenylpyrophosphatase
(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 ◦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 ◦C.