Interaction of polysaccharides on gel characteristics and protein microstructure of threadfin bream surimi gel

Abstract

SummaryPolysaccharide is widely used to improve gel characteristics of surimi gel. The impacts of the polysaccharides tamarind kernel powder (TKP) and tapioca starch (TS) at concentrations of 0%, 2.5% and 5% by weight were investigated on protein conformation [Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM)] and textural characteristics (rheological property, gel strength, solubility, SH contents) of threadfin bream surimi gel. Higher G′ and G″ values were observed in surimi paste added with TKP. Hydrogen bonding increased at higher concentrations of polysaccharides. Addition of TS increased hydrophobic interaction and promoted alteration of the α‐helix to the β‐sheet in the gel structure, while adding TKP to surimi gel had the opposite effect. FTIR images indicated that higher concentrations of polysaccharides resulted in abundant specific polysaccharide functional groups. Microstructures of surimi gel with TKP exhibited an irregular network, with large voids leading to decreased gel strength, while addition of TS increased network density, promoting higher gel strength.