Modulating techno-functional and flavor binding characteristics of pea protein through ultrasound mediated dextran conjugation: Impact of power levels and underlying mechanism

This study investigates the influence of ultrasound-assisted Maillard conjugation on the aroma-binding and techno-functional properties of pea protein-dextran conjugates. Despite increasing interest in enhancing plant protein functionality, the effects of conjugation on protein-aroma interactions, particularly under varying ultrasound intensities, remain largely unexplored. To address this gap, four ultrasound amplitudes (25-100 %) were compared with a traditional 15-min wet-heating method. Conjugation was confirmed through glycation degree, browning index, Maillard reaction indicators, and FT-IR spectral changes. Aroma profile and binding behavior were evaluated using headspace analysis via Selected Ion Flow Tube Mass Spectrometry (SIFT-MS). Ultrasound up to 50 % amplitude enhanced glycation efficiency and significantly improved solubility (from 35 % to over 71 %), oil-binding capacity, emulsification indices, and foaming properties, while reducing water-holding capacity. Although conjugation was a short-term process, the formation of Maillard-derived volatiles such as furans, alcohols, pyrazines, and sulfur compounds was observed, which declined at the highest ultrasound intensity. The interaction of octanal (aldehyde) and 2-octanone (ketone) with the protein was improved under optimal conjugation conditions in controlled aroma-binding assays. These changes were correlated with alpha-helix, beta-sheet, and random coil content, as well as with denaturation temperature and enthalpy, zeta potential, solubility, and conjugation degree.