Yueqi An1, Qing Liu1, Yaru Xie1, Shanbai Xiong1,2, Tao Yin1, Ru Liu1,2. 1. College of Food Science and Technology/National R&D Branch Center for Conventional Freshwater Fish Processing (Wuhan), Huazhong Agricultural University, Wuhan, China. 2. Collaborative Innovation Center for Efficient and Health Production of Fisheries, Hunan, Changde, China.
Abstract
BACKGROUND: Ultrasound and Ca2+ have been used separately to increase myosin properties in fish processing. However, little is know about how myosin changes are affected by Ca2+ and ultrasound in combination. The present study aimed to investigate the effects of the ultrasound-calcium combination system on aggregation and conformational changes of silver carp myosin. RESULTS: Ultrasound facilitated a Ca2+ -induced increase in turbidity. As the Ca2+ concentration increased from 0 to 100 mmol L-1 , there was an obvious increase in the turbidity, solubility and mean hydrated particle size of myosin after ultrasound treatment compared to without treatment. Moreover, changes of total and reactive SH contents depended on the ultrasound-calcium combination conditions. Under this combination system, myosin surface hydrophobicity significantly increased for the synergistic effect of ultrasound and Ca2+ . Furthermore, the ultrasound-calcium combination conditions could affect myosin gelation, with better gelation properties being observed for myosin treated with a combination of 60 mmol L-1 Ca2+ and 9 min of ultrasound. CONCLUSION: The combination system reported in the present study was beneficial for myosin unfolding, facilitating intermolecular interactions between Ca2+ and myosin. Ultrasound treatment promoted myosin aggregation via the induction of Ca2+ and reduced the critical concentration of Ca2+ required to aggregate myosin. In the fish processing industry, this combination system can enhance the gelation properties of surimi-based products.
BACKGROUND: Ultrasound and Ca2+ have been used separately to increase myosin properties in fish processing. However, little is know about how myosin changes are affected by Ca2+ and ultrasound in combination. The present study aimed to investigate the effects of the ultrasound-calcium combination system on aggregation and conformational changes of silver carp myosin. RESULTS: Ultrasound facilitated a Ca2+ -induced increase in turbidity. As the Ca2+ concentration increased from 0 to 100 mmol L-1 , there was an obvious increase in the turbidity, solubility and mean hydrated particle size of myosin after ultrasound treatment compared to without treatment. Moreover, changes of total and reactive SH contents depended on the ultrasound-calcium combination conditions. Under this combination system, myosin surface hydrophobicity significantly increased for the synergistic effect of ultrasound and Ca2+ . Furthermore, the ultrasound-calcium combination conditions could affect myosin gelation, with better gelation properties being observed for myosin treated with a combination of 60 mmol L-1 Ca2+ and 9 min of ultrasound. CONCLUSION: The combination system reported in the present study was beneficial for myosin unfolding, facilitating intermolecular interactions between Ca2+ and myosin. Ultrasound treatment promoted myosin aggregation via the induction of Ca2+ and reduced the critical concentration of Ca2+ required to aggregate myosin. In the fish processing industry, this combination system can enhance the gelation properties of surimi-based products.