Combined tuning of brown rice starch architecture via dielectric barrier discharge plasma and Lycium barbarum peptides: multi-scale structural and physicochemical enhancement

Brown rice has great nutritional values and gradually becomes an excellent health-focus staple to consumers. While it seriously suffers from starch retrogradation, resulting in poor textural quality and limited shelf life. This study investigated the effects of combined treatment of dielectric barrier discharge (DBD) and Lycium barbarum peptides (LBP) on the structural and physicochemical properties of brown rice starch (BRS). The results revealed that DBD, LBP, or their combined treatments significantly affected the structural features of BRS, including a decrease in the amylose content, relative crystallinity, molecular weight distribution of amylose and amylopectin, short-range ordering, and the ratio of double-helix structure; while the proportion of amorphous structure increased. We also found that amylopectin branch chain length distribution shifted to shorter chains (A and B1 chains), especially in DBD- and combined-treated samples. Moreover, these modifications reduced the gel structure strength, pasting viscosity, and disrupted water-binding capacity shifting to more free water, drastically retarding the retrogradation behaviors of BRS. Significantly, dual modification outperformed individual treatments and showed more noticeable and functional properties. This enhancement could be ascribed to the depolymerization and etching effects of DBD treatment improved the accessibility for hydrogen bond interactions between LBP and BRS, highlighting a green strategy to fundamentally inhibit BRS retrogradation. The combination of DBD and LBP offers a promising approach for designing stable, high-quality starchy foods with extended shelf-life and advances the application of physical-biological combinatorial starch modification.