Improving interface properties of zein hydrolysis and its application in salad dressing through dispersion improvement assisted by potassium oleate aqueous solution

Abstract

Zein hydrolysis is difficult to achieve due to a high content of hydrophobic amino acids and poor solubility, which limits its application in the food industry. Potassium oleate, an anionic surfactant, can interact with globular proteins to improve properties. In this paper, potassium oleate was used to construct a new reaction system to improve the solubility of zein and to improve the interfacial properties of zein by enzymatic hydrolysis. Results showed that zein solubility increased by 65.48% at potassium oleate concentration of 10 g/L. The surface hydrophobicity of zein decreases with the increase of enzymolysis time. Compared to zein without enzyme treatment, the emulsification activity and emulsification stability of zein increased by 3.57 and 4.63 times, and the foaming capacity and foaming stability increased by 73.45% and 44.65% when the enzymatic hydrolysis time is 10 min. The static and dynamic rheological results show that the rheological properties of enzymatically hydrolyzed zein solution as a fat substitute when replacing 10% of oil are most similar to those of full-fat salad dressing. This study may offer a facile approach to develop novel food-grade material, which are beneficial for the better application of zein in the food industry.