Abstract

This study investigates the enzymatic remodelling of chickpea and pea protein isolates to improve performance in high-temperature, foamed beverages. Proteins were treated with microbial transglutaminase (TG) under conditions that favour deamidation rather than crosslinking, and structural, thermal, and functional changes were assessed using Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), amino acid profiling, and foaming assays. TG treatment increased ammonium release and shifted glutamine and asparagine toward glutamic and aspartic acids, confirming deamidation-dominant reactivity. Moderate increases in beta-sheet structures, matrix-dependent thermal stabilization, reduced water-holding capacity, and enhanced oilholding capacity were observed. Functionally, treated proteins showed higher foam capacity and longer foam half-life, especially in chickpea, where foam expansion increased 10-15% and foam half-life was extended, consistent with increased interfacial elasticity. Essential amino acids remained preserved. These findings identify controlled enzymatic deamidation as a clean-label strategy to enhance heat stability and foaming functionality of legume proteins for plant-based barista applications.