Effect of optimized germination on nutritional functional and phytochemical characteristics of green gram

Abstract Germination is an effective bioprocessing strategy for enhancing the nutritional quality and functional potential of legumes. This study systematically evaluated the effects of controlled germination on the nutritional, functional, phytochemical, antioxidant, and sensory characteristics of ten elite green gram (Vigna radiata L.) cultures, with the objective of identifying genotypes suitable for sprout-based functional food applications. Germination was conducted for 8, 12, 16, and 20 h, and optimization was achieved based on overall sensory acceptability (OSA) score using a nine-point hedonic scale. The highest sensory acceptability scores, ranging from 6.01 to 8.60, were observed at 8 - 12 h of germination, whereas extended germination significantly reduced acceptability due to the development of bitterness. Compared with non-germinated samples, optimally germinated green gram cultures exhibited significant improvements in nutritional composition, including increased crude protein content from 17.38 – 24.81 to 20.12 - 26.32 g 100 g⁻1 and crude fiber from 9.86 - 13.82 to 11.36 - 16.42 g 100 g⁻1. Ash content also increased marginally following germination. Vitamin C, which was absent in raw grains, was synthesized during germination and reached levels of approximately 55.04 to 85.48 mg 100 g⁻1. In contrast, anti-nutritional factors were substantially reduced, with tannin content decreasing from 320 - 458 to 65 - 97 mg tannic acid equivalent 100 g⁻1 and phytic acid from about 754 - 906 to 102 - 175 mg 100 g⁻1. Germination significantly enhanced phytochemical composition and antioxidant capacity, as evidenced by increased total phenolic and flavonoid contents and higher DPPH radical scavenging activity, which increased from 23.78 - 32.41% in raw grains to 35.47 - 40.59% in germinated samples. Functional properties, including water and oil absorption capacities, were also significantly improved following germination. Overall, this study presents a novel comparative screening of elite green gram cultures and establishes optimized germination as a practical and scalable approach for developing green gram sprouts in both fresh and dry forms in salads, weaning/supplementary foods, nutrient-dense convenience foods, etc., for improved nutrition.