Development of freezing-point regulators for cultured large yellow croaker

The influence of temperature, freezing medium, water content and size of fish cakes on the freezing process of large yellow croaker (LYC) were investigated systematically. Then the effects of freezing point regulators such as sodium chloride, sucrose, sorbitol, vitamin C and glucose were analysed by response surface methodology. The variables ranges used according to the single factor experiment were 3-7% sodium chloride (w/w), 5-9% sorbitol (w/w) and 2-3% sucrose (w/w) and the responses were optimised by a numerical method and were found to be 5.16% sodium chloride (w/w), 7.15% sorbitol (w/w) and 2.96% sucrose (w/w). All the derived mathematical models for the responses were found to be a significant fit for the predicted data. The results show the freezing point of LYC decreased from -1.5 to -4.2 °C after adding the optimised freezing point regulators, and the texture parameters were not significantly affected in comparison with the control group.