Effects of vacuum chopping on physicochemical and gelation properties of myofibrillar proteins from silver carp (Hypophthalmichthys molitrix).

Physicochemical and gelation properties of myofibrillar proteins from silver carp surimi as affected by chopping under different vacuum degrees (0, 0.01, 0.02, 0.04, 0.06 and 0.08 MPa) were investigated. With the increase of vacuum degree, size and quantity of air bubbles in surimi paste decreased, disulfide bond content of myofibrillar proteins decreased significantly (p < .05) and then slight increased (p > .05), while surface hydrophobicity of myofibrillar proteins increased gradually (p < .05). Gel mechanical properties, chemical interactions (nonspecific associations, hydrogen bond and hydrophobic interactions) and FAXL (cross-linking degree of free amino group) of heat-induced surimi gel increased significantly (p < .05) with vacuum degree. Scanning electron microscopy (SEM) observation showed that three-dimensional network of surimi gel under higher vacuum degree was more compact and orderly. Results indicated that vacuum chopping imparted physicochemical and structural changes of fish myofibrillar protein, which might contribute to the improvement in gelling properties of myofibrillar proteins.