Pulsed light treatment enhances starch hydrolysis and improves starch physicochemical properties of germinated brown rice.

BACKGROUND: Recently, germinated brown rice (GBR) has gained substantial attention as a functional food because of its nutritional attributes. Notably, pulsed light technology (PLT) has emerged as a promising tool for enhancing rice germination and, consequently, has improved the nutritional and functional qualities of GBR-derived products. However, further research is required to comprehensively understand the impact of PLT on GBR physicochemical properties. The present study aimed to investigate the stimulating effects of PLT on starch hydrolysis, starch structure and functional properties of GBR. RESULTS: The PLT substantially boosted α-amylase activity during brown rice germination, leading to a 10.9% reduction in total starch content and a 17.3% increase in reducing sugar content, accompanied by elevated free water levels. Structural analysis indicated no changes in starch crystalline types, whereas gelatinization temperature slightly increased. Pasting properties exhibited a significant drop in peak viscosity. Scanning electron microscopy showed surface erosion of starch granules with microstructural changes. Furthermore, correlation analysis established positive links between α-amylase activity, reducing sugar accumulation, starch structure and functional properties in GBR. CONCLUSION: The present study demonstrates that PLT enhanced the physicochemical properties of GBR starch, significantly improving the stability of GBR products, thereby contributing to expanded applicability of rice starch in the food industry. © 2023 Society of Chemical Industry.

Combined transcriptome and metabolome analyses reveal the mechanism of abundant bioactive compounds and high antioxidant activity in germinated weedy rice.

Germinated brown rice has recently garnered widespread attention due to its high nutritional value. Previous research demonstrated that the bioactive components and functional properties of germinated brown rice varieties exhibit significant differences. Three germinated rice cultivars weedy rice WR04-6 (WR) and two cultivated rice cultivars with superior eating quality, Koshihikari (YG) and Daohuaxiang (DHX), were analyzed using metabolites and transcriptome profiling. Widely targeted metabolomics results showed that 85.9% and 71.2% of differential metabolites for WR vs. YG and WR vs. DHX were enriched in WR, respectively. The substances mainly included amino acids and derivatives, carbohydrates and its derivatives, organic acids and its derivatives, and flavonoids. Higher antioxidant activity was detected in WR compared to cultivated rice in metabolome analysis. Transcriptome analyses indicated that 18 responsive genes played pivotal roles in the conversion of key metabolites. These findings will provide theoretical underpinnings for the development of rice germplasm resources and the formulation of functional germinated grain foods.