Influence of combined salt concentration and low-frequency ultrasound on physicochemical and antioxidant properties of silver carp myofibrillar protein

Abstract

The present work aimed to evaluate the combined influences of salt sodium chloride (NaCl) concentration and low-frequency ultrasound on the functionality of silver carp myofibrillar protein (MP). Silver carp MP was set using different salt concentrations (0.2, 0.4, 0.6, and 0.8 M NaCl) and low-frequency ultrasound treatment (12 min, 350 W). The samples showed a high solubility (85.30 - 93.80%) across various treatments. The turbidity was lowered significantly by increasing the salt concentration with no sonication, while the turbidity changes were insignificant with the combination treatment (NaCl + U12). Ultrasonic treatment of combined 0.4 M salt (NaCl 0.4 M + U12) achieved the highest water holding capacity (WHC) making up 6.46 g water/g MP. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) inhibition ranged from 16.33 to 43% and 13.27 to 25.69%, respectively, and the highest values were shown in the sample containing 0.4 M salt with sonication (NaCl 0.4 M + U12). It could be concluded that the best treatment was ultrasonic with 0.4 M salt (NaCl 0.4 M + U12). The treatment provided the optimal antioxidant activity with good protein solubility and WHC. The integrated results indicate that employing NaCl with ultrasonic treatments (NaCl + U12) could improve the functionality of silver carp MP. These results are very promising for increasing the potential advantage of this fish species as the sources of proteins for several applications.