Ultrasonic pretreatment and epigallocatechin gallate incorporation enhance the formation, apparent viscosity, and antioxidant activity of pea protein amyloid-like fibrils

Research on the application of plant protein-based carrier in the field of food is increasing in recent years. Pea protein, a critical plant protein source in food processing, has the advantages of high nutritional value, low price and low allergy. In this study, the effects of pre-ultrasonic treatment on the fibrillation behavior of pea protein, the microstructure, rheological property and antioxidant activity of pea protein amyloid-like fibrils as well as the interaction between epigallocatechin gallate and pea protein amyloid-like fibrils were examined. Thioflavin T fluorescence illuminated pre-ultrasonic treatment could dramatically facilitate the formation of beta-sheet structure. Interaction between epigallocatechin gallate and pea protein fibrils was mainly through hydrophobic interaction, evidenced by intrinsic fluorescence spectroscopy, X-ray diffraction and surface hydrophobicity analysis. Antioxidant properties and apparent viscosity of pea protein fibrils were remarkably enhanced with both ultrasound and epigallocatechin gallate addition. The pre-ultrasound treated amyloid-like fibrils were more slender than those without treatment in terms of morphology. It was found that pre-ultrasound treated pea protein fibrilsepigallocatechin gallate composites exhibited the highest stability, viscosity and antioxidant activities, which showed great promising as excellent carriers of bioactive substances. The results obtained in this study could enable the utilization of pea protein fibrils-based hydrogel for stabilizing, encapsulating, and delivering bioactive compounds in food processing.