The Binding Mechanism of 2,5-Dimethylpyrazine with Amyloid Fibrils Derived from Different Protein Sources

Abstract This study systematically investigated the binding patterns and interaction mechanisms between protein amyloid fibrils formed via acid-heat treatment from different sources (soybean, pea, rice, gluten) and 2,5-dimethylpyrazine. The results indicated that fibrillation modification of proteins significantly enhanced their binding capacity for aroma molecules. However, differences in microscopic morphology, structural characteristics, and physicochemical properties among amyloid fibrils from different protein sources directly affected their binding capacity and the thermal stability of binding to 2,5-dimethylpyrazine. Among them, pea amyloid fibrils (PAFs) exhibited a high binding ratio of 36.64% and demonstrated good binding thermal stability across different temperatures (50–120 °C). The superior aroma-binding capability of PAFs was closely associated with their high surface hydrophobicity, abundant β-sheet content, and regular aggregation-state morphology. Spectroscopic and thermodynamic analyses further revealed distinct binding mechanisms among the different protein amyloid fibrils and the aroma molecule: hydrophobic interactions dominated for SAFs, van der Waals forces and hydrogen bonds were primary for PAFs, while electrostatic interactions were predominant for RAFs and GAFs. This research provides a theoretical basis for the design and screening of aroma stabilization in plant-based meat, holding significant application value for improving the flavor quality of plant-based foods.