Concentration-Dependent Effect of Shrimp Head Protein Hydrolysate on Freeze-Induced Denaturation of Lizardfish Myofibrillar Protein during Frozen Storage

Abstract

With the aim of finding an effective way of utilizing shrimp waste, the suppression of freeze-induced denaturation of lizardfish myofibril by proteolytic shrimp head protein hydrolysates (SHPH) during frozen storage at -25°C was investigated by determining the amount of unfrozen water and Ca-ATPase activity in myofibrillar samples containing SHPH from three different species of shrimp at various concentrations (2.5-10% dried matter). The amount of unfrozen water increased markedly after freezing and decreased gradually during frozen storage in the samples containing SHPH, regardless of shrimp species. Over 120 days of storage, the Ca-ATPase activity of myofibril containing SHPH slowly decreased, whereas that of the control fell drastically after the initial freezing. These results suggest that the interactions between myofibrillar protein and the active components of SHPH, such as hydrophilic amino acids and peptides, may retard freeze-induced denaturation in fish myofibril during frozen storage. SHPH exhibited optimum suppression of freeze-induced denaturation at concentrations of 5-7.5%, regardless of species differences.