Rice dreg protein as a high-quality plant-based protein resource: Characterization of structural, functional, and in vitro digestive properties

Background and Objectives

Rice dregs, a by-product of the process of making sugar from broken rice, have a protein content of up to 70%. However, rice dreg protein (RDP) has not yet been fully utilized due to its high-temperature liquefaction denaturation during sugar production. In this study, the structural, functional, and in vitro digestive properties of rice protein (RP) extracted from broken rice and RDP derived from rice dregs were compared, with a view to providing a basis for further utilization of RDP.

Findings

Although RDP was a heat-denatured protein, it was found to have relatively better functional properties and a well-balanced amino acid composition. Structural analysis results revealed that RDP showed a looser and disordered structure. However, SDS-PAGE results showed that the subunit composition of the two proteins was similar. The in vitro simulated digestion results showed that the digests of RDP had higher antioxidant and ACE inhibitory activity, but RDP showed significantly lower digestibility than RP.

Conclusions

Through relevant modifications of RDP, RDP has the potential to be a good source of high-quality protein in the human diet as the demand for plant-based protein increases.

Significance and Novelty

This study can provide a basic theoretical basis for further development and utilization of RDP, which is also of great practical significance for seeking new plant protein resources and increasing the added value of broken rice.