PROCESSING EFFECTS ON ANTI-NUTRITIONAL FACTORS, PHYTOCHEMICALS, AND FUNCTIONAL PROPERTIES OF HORSE GRAM (MACROTYLOMA UNIFLORUM) FLOUR

Abstract

The work aimed to study the effect of processing methods, namely soaking, fermentation, germination, and roasting on anti-nutritional compounds, phytochemicals, and functional property of horse gram flour. Horse gram was soaked in water (1:3 w/v) up to 24 h to get soaked horse gram. While after 12 h soaking in water (1:2 w/v) seeds were ground into a slurry and allowed to ferment naturally for 48 h in a sterile flask. The soaked seeds after 24 h were spread in a muslin cloth to germinate for 72 h at 27±3°C, 90% RH. The unsoaked seeds were roasted on low flame for 10 min in an iron pan. Treated horse gram seeds were then dried in a cabinet drier at 50°C for 24 h except for roasted horse gram, and milling was done to get the flour. Anti-nutritional factors were significantly reduced after fermentation, particularly phytic acid, tannin and oxalate content were reduced by 69.5, 69.3, and 66.7 % respectively while reduction during germination was 61.6, 54.6 and 61.6 % respectively. But, soaking and roasting reduced polyphenols and flavonoids content. Meanwhile, increment in phytochemicals was observed during germination (26% and 30.7%) and fermentation (86.9% and 53.8%) respectively. In the case of antioxidant content, it decreased during soaking (28.7%) while increases during roasting (29.1%), germination (51.6%) and fermentation (59.9%). Bulk density and viscosity decreased during treatment, while water absorption capacity and oil absorption capacity increased in treated horse gram flour. The study showed that germination and fermentation can produce a significant reduction in the anti-nutritional factor and a considerable rise in bioactive components along with the improved functional property of horse gram flour as compared to the untreated one.