Ultrasound-assisted Maillard reaction of ovalbumin/xylose: The enhancement of functional properties and its mechanism

This study aims to optimize the ultrasound treatment conditions for enhancing the degree of glycation (DG) of ovalbumin (OVA)-xylose conjugates through Maillard reaction and investigate the correlation between DG and functional properties affected by structural changes. The structural and functional properties of classical heating OVA, glycated OVA, ultrasonic treated OVA, and ultrasound-assisted glycated OVA were investigated to explore the interaction mechanism of ultrasound treatment on foaming and emulsifying properties improvement. Results indicated that the ultrasound assistance increased free sulfhydryl content, surface hydrophobicity and particle size of OVA-xylose conjugates, and thus enhancing the surface properties, which were strongly linear correlated with DG under different glycation parameters (pH, xylose/OVA ratio, heating time). Additionally, circular dichroism spectroscopy analysis revealed that ultrasound promoted the conversion of α-helices to β-sheets and unfolded structures, which was consistent with the formation of short amyloid-like aggregates that observed by atomic force microscopy phenomenon. Overall, our study provides new insights into the effects of ultrasound treatment on Maillard-induced protein functional properties enhancement, which may be a new strategy to tune the DG and functionality of protein-saccharide grafts during ultrasound processing.