Germination conditions for brown rice (Oryza sativa L.) and its application in beverage production

Sprouted brown rice (Oryza sativa L.) has significantly higher levels of bioactive compounds than unsprouted rice, such as phenolics, γ-aminobutyric acid, and vitamins. This study aimed to optimize processing parameters to develop a germinated brown rice beverage combined with green tea that has superior sensory quality, nutritional value, and storage stability. The main parameters under study included soaking time (0–24 h) and germination time (0–4 days). After germination, the rice was subjected to high-temperature treatment at 180°C for different durations (4–16 min). The extraction time using water as the solvent ranged from 5 to 20 min, and the mixing ratios of germinated rice extract and green tea were 4:6, 5:5, and 6:4. Based on the results, the optimal conditions for producing high-quality products were: soaking for 12 h to achieve maximum moisture content, germinating for 3 days to maximize germination rate and polyphenol content, high-temperature treatment for 8 min to achieve the desired color and sensory characteristics, extracting for 15 min, and a 6:4 mixing ratio (germinated rice:green tea) for a balanced and acceptable flavor. The resulting beverage showed stability when stored at 30°C, retaining approximately 70% of the total polyphenol content after 72.68 days, as predicted by the Q10 shelf-life model. These findings provide a scientific basis for developing functional beverages derived from sprouted brown rice with enhanced biological properties and extended shelf life.