Impact of different ultrasonication strategies on the structural, rheological, and functional properties of mung bean protein isolate–gum arabic conjugates formed via the Maillard reaction

Abstract BACKGROUND The impact of different ultrasound (US) strategies on the formation of mung bean protein isolate–gum arabic (MBPI–GA) conjugates formed by the Maillard reaction was investigated to overcome the techno‐functional limitations of native mung bean protein isolate (MBPI). Two primary sonication strategies – pre‐sonication of protein (P100, P200) and co‐sonication of the protein‐polysaccharide mixture (PG100, PG200) – were compared with traditional wet‐heating controls. RESULTS High‐intensity ultrasound (200 W) significantly accelerated Maillard reaction kinetics, resulting in the highest degrees of grafting (44% to 47%) compared with wet‐heated MBPI–GA conjugates without ultrasound treatment. Fourier transform infrared (FTIR) spectroscopy and reactive sulfhydryl group analyses confirmed that ultrasonic cavitation induced structural unfolding, as evidenced by a significant reduction in ‐sheet fractions and a concomitant increase in random coil content, exposing buried reactive sites. All sonicated conjugates exhibited more than a twofold increase in protein solubility compared with the native protein. The PG200 strategy maximized emulsifying activity index (EAI) and water‐holding capacity (8.5 g g −1 ), and PG100 yielded the highest in vitro protein digestibility (approximately 60%) and improved thermal stability. The denaturation temperature () increased from 81.32 °C (native MBPI) to 82.65–83.63 °C in the co‐sonicated conjugates, accompanied by a pronounced reduction in denaturation enthalpy () from 15.7 to 5.5 J g −1 . Rheological assessments revealed that the conjugates formed a heat‐stable, liquid‐like network in which the loss modulus () consistently exceeded the storage modulus (), thereby preventing thermal gelation and precipitation during processing. CONCLUSION These findings suggest that co‐sonication of MBPI–GA mixtures is a highly effective green modification strategy for producing homogeneous, functional, and highly digestible plant‐based biomacromolecules. The resulting conjugates show considerable potential for use in liquid food formulations and high‐temperature industrial processes. © 2026 Society of Chemical Industry.