Effects of ultrasound combined with pH-shift assisted glycosylation modification on the structural and functional properties of by-product proteins extracted from shrimp heads

A protein isolated from the heads of <i>M. rosenbergii</i> shrimp (MHPs), a shrimp by-product, possesses high nutritional value, but its low solubility limits its application. This study examined the effects of ultrasound coupled with the pH-shift assisted glycosylation modification of MHPs on the physicochemical properties and epigallocatechin gallate (EGCG) loading capacities of the proteins. The results indicated that ultrasound coupled with pH-shift assisted glycosylation effectively enhanced the glycosylation degree of MHPs to 48.3 %. MHPs processed by this method exhibited looser spatial structures, higher thermal denaturation temperatures (98.5 °C) and lower interfacial tension, which facilitated the formation of a denser, more ordered network at the oil/water interface. These favorable changes effectively improved the solubility, oil/water adsorption capacity and emulsifying performance of MHPs. Notably, the MHPs modified using ultrasound coupled with pH-shift assisted glycosylation had a higher EGCG loading capacity, and the prepared MHP-EGCG complex exhibited an excellent antioxidant capacity.