Characterization of enzyme-hydrolyzed vegetable proteins from mung bean, soybean, and pea and their roles in the formation of volatile compounds by thermal interaction with reducing sugars

The development of plant-based foods with desirable meaty and savory flavors remains challenging due to differences in protein composition and flavor precursors compared with animal proteins. The objective of this study was to systematically compare the physicochemical properties and flavor-producing potentials of enzyme-hydrolyzed vegetable proteins (EVPs) derived from mung bean, soybean and pea. Degree of hydrolysis, molecular weight distribution, and free amino acid profiles were determined, and volatile compounds generated through Maillard reactions with reducing sugars were analyzed. Our results showed that the mung bean EVP exhibited the highest degree of hydrolysis, whereas that from soybean showed the lowest. Pea EVP contained the highest total content of free amino acids, while that of soybean contained the lowest. Leucine and lysine were abundant in all EVPs, whereas sulfur-containing amino acids were relatively limited. Principal component analysis revealed that both EVP type and reducing sugar significantly influenced volatile compound profiles. EVPs from mung bean and pea produced greater amounts of Strecker aldehydes, heterocyclic compounds, and sulfur-containing compounds than soybean hydrolysate. These findings demonstrate that the intrinsic properties of EVPs critically influence Maillard reaction-driven flavor formation and provide practical insights for selecting plant protein sources to enhance flavor characteristics in plant-based food applications.