Abstract: The purpose of this study was to investigate the effect of sugars with different molecular weights on structural, functional and rheological properties of plant protein modified by Maillard reaction. Crosslinked rice dreg protein by transglutaminase (TGase) was used for glycosylation reaction in a wet state with ribose, glucose, lactose, or gum arabic, and then the properties of Maillard reaction products (MRPs) were analyzed. The results showed that as the reaction proceeded, the degree of substitution (DS), pH and degree of browning (DB) of the system changed significantly, and the most evident changes were observed when ribose and glucose were involved in the reaction, followed by lactose and gum arabic. The structure of ribose made it susceptible to reaction with free amino groups such as Lys and Arg in rice dreg protein (RDP). The solubility and emulsifying properties of MRPs from theses sugars were enhanced in varying degrees, and the decreasing order was ribose, glucose, lactose, and gum arabic. Rheological data indicated that all samples were pseudoplastic fluids, whose apparent viscosity showed a shear-thinning phenomenon, and the apparent viscosities of MRPs from glucose and ribose were larger than that of crosslinked RDP, while those of MRPs from lactose and gum arabic were smaller.

Key words: transglutaminase crosslinked rice dreg protein, Maillard reaction products, glycosylation reaction, structure, functional properties