Comparison of ovalbumin glycation by microwave irradiation and conventional heating

Solid-state ovalbumin (OVA)-glucose (1:1) mixture was subjected to 480 and 640 W of microwave irradiation (MI) and equivalent conventional heating (CH) for 5, 10 and 15 min. The effects of MI and CH on protein antioxidant activities, emulsifying properties, glycation rate and structural properties were compared. The OVA antioxidant activities, emulsifying activity and emulsion stability increased with the increase in processing time. The improvements were more pronounced under MI than that under CH. The free amino group contents decreased, and the UV-vis absorbance alteration and SDS-PAGE pattern indicated that MI could accelerate the OVA glycation particularly at high power level and resulted in higher glycation rate than that of CH. The secondary and tertiary protein structures were altered by MI and CH at varying degrees. Accordingly, MI could be a new efficient technology that could promote OVA glycation, change protein conformational structure and considerably improve the antioxidant activities and functional properties of protein.