Prevention of frozen-dough from deterioration with incorporation of glutenin-polyphenols conjugates prepared by ultrasound

The development of protein-polyphenol conjugates is attracting more research interest in recent years due to their potential application in food industry. In this study, three types of polyphenols (proanthocyanidin, catechin and curcumin) was conjugated with glutenin by radicle polymerization induced from ultrasound treatment. The conjugates showed decreased content of free amino groups and sulfhydryl, which can be evidence of formation of conjugates between glutenin and polyphenols. Conjugation with polyphenols led to disruption of hydrogen bonds, changes in tertiary and secondary structure, increasing of particle size and charge density of glutenin. Furthermore, the incorporation of conjugates can improve the viscoelasticity properties of frozen dough, which was proved by the increasing of complex modulus and decreasing of creep compliance values. The microstructure observation revealed that the conjugates played an important role in the development of gluten network, which could prevent the frozen dough from deterioration. In addition, the incorporation of conjugates also improved the loaf volume and hardness of frozen dough bread.