Application of a biogenic extra cellular ice nucleator for food processing: effects on the freeze‐thaw stability of fish actomyosin from <i>tilapia</i>

Abstract

Summary The effect of biogenic extra cellular ice nucleators (ECINs) on gel‐forming capacity and textural stability of a fish actomyosin (AM) gel system subjected to controlled freeze‐thaw (FT) cycles was studied. Stability changes were quantified by measuring the degree of retention of Ca 2+ ATPase activity and changes in protein surface hydrophobicity. Results showed that different concentrations of ECIN suppressed Ca 2+ ATPase activity loss during FT cycles depended quantitatively on ECIN concentration. After three FT cycles, Ca 2+ ATPase activity retention was 76.20% with the highest ECIN concentration and 20.10% without ECIN, and surface hydrophobicity of AM with ECIN was 150.67, whereas the corresponding value of the control sample was 208.70. By measuring changes in surface hydrophobicity, we observed that ECIN significantly reduces denaturation of AM protein caused by FT cycling. Our data show that ECIN contributes a significant protective effect on gel‐forming capacity of fish and textural stability of fish AM during FT cycling. This demonstrates for the first time that ECINs have the potential to help stabilise the texture of fish AM and potentially other food products during frozen storage.