Total Phosphorus, Phytate Phosphorus Contents and the Correlation with Amylose in Selected Edible Beans in Sri Lanka

Legumes of eleven varieties cultivated in Sri Lanka, Mung bean (MI5, MI6), Cowpea (Waruni, MICP1, Bombay, Dhawala, ANKCP1), Soybean (MISB1, Pb1) and Horse gram (ANKBlack, ANKBrown) were analyzed for phosphorus content and phytate content. Total phosphorus content was quantified by dry ashing followed by spectrophotometrical measurement of acid soluble Phosphate-Molybdate complex, while phytate phosphorus using anion exchange chromatographic technique followed by spectrometrical measurement of the digested organic phosphorus and amylose content by Simple Iodine-Colourimetric method. Where the least value for phosphorus was observed 275.04 1.44 mg/100g in ANKBlack and the highest in MISB1 with 654.94 0.05 mg/100g. The phytate phosphorus content (which is a ratio of phyate to total phosphorus) was highest in Dhawala. The phytate phosphorus was highest in Dhawala with 67.42 % and least in Bombay with 24.87 %. The amylose content of the legumes was least in Pb1 with 8.71 0.13 mg/100mg and the highest in MI6 22.58 0.71 mg/100mg. The correlation between total phosphorus with phytate and phytate phosphorus were significant (p less than 0.05) and positive (r = 0.62 and r = 0.63). Amylose content of legumes was significantly correlated negatively (p less than 0.05) with the total phytates content (r = -0.82).