Reductions of anti-nutritional factors of germinated soybeans by ultraviolet and infrared treatments for snack chips preparation

Ultraviolet (UV) and infrared (IR) treatments were conducted to reduce anti-nutritional factors of 5-day germinated soybean. Exposure time/duration and distance/height to UV/IR were 24/48/72 h for UV treatment at 7/17/27 cm distance and 1.0/1.5/2.0 h for IR treatment at 15/20/25 cm distance. These resulted in significant reductions (P < .05) of lipoxygenase-1, lipoxygenase-3, and trypsin inhibitor activities to 24, 83, and 50% respectively for UV treatment (17-cm distance, 24-h exposure) and 31, 95, and 98% respectively for IR treatment (15-cm distance, 1.5-h exposure). When combined, as the optimal treatment, the highest reduction was obtained (55, 97, and 99% reduction in lipoxygenase-1, lipoxygenase-3, and trypsin inhibitor activities respectively). Chemical analysis showed that chips made from UV-IR treated germinated soy had moisture, protein, starch, and lipid contents of 4.0, 46, 15, and 11 g/100 g respectively. These chips also had the lowest anti-nutritional factors due to high reductions in lipoxygenase-1 (62%), lipoxygenase-3 (98%), and trypsin inhibitor activities (100%) and low estimated glycemic index (13). However, the chips had low scores for flavor (3.3), texture (4.9), and overall impression (3.6) for their sensory analysis. Despite low in soybean anti-nutritional factors for these chips, improvement in consumer acceptance is required.