The effect of modified starches on the gel properties and protein conformation of Nemipterus virgatus surimi.

ABSTRACT

The study investigated the effect of native cassava starch (NCS), hydroxypropylated starch, acetic acid esterification starch (AAES), acetylated distarch phosphate on gel properties and protein conformation of Nemipterus virgatus surimi. Addition of 10 g kg-1 NCS or 20 g kg-1 AAES could significantly promote the gel strength and textural profiles of the surimi gels (p < .05). The water holding ability and whiteness of surimi were remarkably increased when the four types of starch were added at all concentrations (p < .05). In rheological test, the lower G' was observed in surimi samples added with starch at low temperature, suggesting starch played an inactive filler role in surimi. Along with the increase of starch additive amount, ionic bond and hydrophobic interaction first increased and then decreased, while hydrogen bond first decrease and then increased. According to Raman spectroscopy data, small content of starch promoted the heat-induced conformational transition of surimi protein from α-helix to ß-sheet, leading to the change in gel properties of surimi gels. Scanning electron microscopy photographs showed surimi gels added with 20 g kg-1 starch had the finer and denser network structure. Therefore, 20 g kg-1 AAES or 10 g kg-1 NCS or 10 g kg-1 HS could be proposed to a potential modifier to effectively improve the quality of surimi products.