Work

Structural changes in starch and protein of brown, red, and black rice flours induced by steam-assisted heat treatment

Year: 2026

Type: article

Abstract: This study investigated the effects of steam-assisted heat treatment on starch and protein structural changes in brown, red, and black rice flours. Starch molecular order and crystallinity were assessed using FTIR, XRD, AFM, SEM, image analysis, and digestibility assays, while protein structure and thiol-disulfide chemistry were evaluated by FTIR and chemical analyses. FTIR indicated increased starch short-range order, with crystallinity rising from ∼62% to ∼67% in brown and red rice starches and from 65.85% to 69.01% in black rice starch. XRD revealed greater increases in long-range crystallinity in brown (25.44% to 47.63%) and red (27.10% to 42.81%) rice starches, with a more moderate increase in black rice. These structural changes promoted resistant starch formation, most prominently in brown rice, followed by red and black rice. Protein analyses showed greater structural stability in red and black rice, whereas brown rice proteins exhibited greater unfolding and aggregation following treatment.

Source: Food Chemistry X

DOI: 10.1016/j.fochx.2026.104688