Comparison of contents of phytates and saponins and the effect of processing in some selected edible beans in Sri Lanka
Keerthana Sivakumaran, MA Jagath Wansapala, HM Theja Herath
Legumes which are important sources of proteins, minerals and vitamins, comprise significant amounts of anti-nutritional factors (ANFs) leading to limited functionality and bioavailability of proteins and minerals. This study was focused on determining the contents of phytates and saponins in eleven legume varieties in Sri Lanka and the effect of processing on their contents. Eleven legume varieties, Mung bean (MI5, MI6), Cowpea (Waruni, MICP1, Bombay, Dhawala, ANKCP1), Soybean (MISB1, Pb1) and Horse gram (ANK Black, ANK Brown) were analyzed to determine the phytate contents on eluted acid extracted fraction from anion exchange chromatographic technique followed by spectrophotometrical determination while saponins by double solvent extraction gravimetric method. Soya bean (Pb1) had the significantly (p ≤ 0.05) highest initial phytate content of (9.12 ± 0. 61 mg/g) and horse gram (ANK Black) had the lowest phytate content (2.60 ± 0. 26 mg/g). Saponin content ranged from (8.01 ± 0.70 mg/g) in soyabean (Pb1) to (12.76 ± 1.28 mg/g) in soyabean (MISB1). Processed legumes, soaking followed by autoclaving, showed a reduction in phytate and saponin contents ranging from 8.34% - 33.05 % and 6.35% - 72.02% respectively.