Glycosylation and Deamidation of Rice Endosperm Protein for Improved Solubility and Emulsifying Properties

Abstract

ABSTRACT Rice endosperm protein was prepared by alkali‐extraction method and subsequently modified by controlled glycosylation (RP Glu , RP XG ), deamidation (RP DA ), and enzymatic hydrolysis by alcalase (RP Alc ) methods. The RP Glu and RP XG were prepared by Maillard type glycosylation with D‐glucose and xanthan gum, respectively. The glycosylation improved the emulsion activity (0.721) and stability (26.8 min) of the protein but did not show a substantial improvement in solubility (39.7%). The rice protein modified by controlled alkali‐deamidation (RP DA ) showed highest solubility (68%), emulsion activity (0.776), and emulsion stability (24 min) among the three protein modification methods evaluated in this study. The alcalase treatment to 1.8% DH (RP Alc ) slightly improved solubility (33%), emulsion activity (0.468), and emulsion stability (17.5 min) compared with unmodified rice protein (RP), which had 18% solubility, 0.266 emulsion activity, and 14.7 min emulsion stability. The glycosylation and deamidation methods were more effective than the controlled enzymatic hydrolysis by alcalase in improving solubility and emulsifying properties of rice endosperm protein. Glycosylated and deamidated rice endosperm proteins can find application in enhancing emulsifying properties in suitable products.