Abstract: Waxy corn starch, esterified waxy corn starch and cross-linked esterified waxy corn starch were added separately to myofibrillar proteins at levels of 0%, 2%, 4%, 6%, 8% and 10% to form protein-starch composites for the purpose of investigating the effects of three starches on the water retention, texture properties, whiteness, surface hydrophobicity, rheology and microstructure of myofibrillar protein (MP) gels. The experimental results showed that addition of starch could significantly improve the water holding capacity, hardness and elasticity of MP gels in a concentration-dependent manner (P < 0.05). These indexes were increased but not significantly at an addition level of 10% (P > 0.05). Cross-linked esterified corn starch was the most effective among the starches. All three starches could increase the whiteness of composite gels, but cross-linked esterified corn starch resulted in an excessively high whiteness value (P < 0.05), which is unfavorable to the color. Meanwhile, all the starches could significantly increase protein surface hydrophobicity and gel elastic modulus (P < 0.05). Compared with MP gels, the composite gel structure tended to be more compact and uniform. The effect of cross-linking esterified waxy corn starch on improving MP gel properties except for color was better than that of the other two starches.

Key words: starch, myofibrillar protein, rheological properties, microstructure