Standardization of Microwave Heating Process Parameters for Extraction of Galactooligosaccharides (GOS) From Ricebean Flour

ABSTRACT Ricebean ( Vigna umbellata ) is a versatile, nutritious crop cultivated in hilly regions, offering significant nutritional contents and serving as a vital livelihood source for the Himalayan population. It has ample amount of nutritional characteristics especially galctooligosaccharides (GOS) which possess prebiotic properties. Therefore, the study was aimed to extract the GOS from ricebean using microwave heating technique. The full factorial design (27 experiments) was applied to optimize the microwave heating process parameters (microwave power: 240–640 W, time: 3–9 min, water to flour ratio: 14:1 to 20:1 mL/g), and its linear and interaction effects of process conditions were evaluated on the GOS yield, total phenolic content (TPC), antioxidant activity (AC) and pH. The GOS, TPC, and AC were significantly ( p < 0.05) influenced by all the process parameters. Microwave power had significant impact on GOS with higher yield 2.58 g/L. In optimization, the best process conditions were obtained at 3 min extraction time, 400 W power, and 14:1 mL/g water to flour ratio with higher desirability (0.77) for maximum GOS yield, TPC, and AC. Moreover, the microwave heating as an ecofriendly technique had the potential to be applied to underutilized pulses (ricebean).