Effect of germination duration on structural and physicochemical properties of mung bean starch

Mung bean seeds were germinated at 25 °C for 12, 24, 36, 48, 60 and 72 h. Changes in structural and physicochemical properties of mung bean starch during germination were investigated. Microscopy analysis showed germination did not change the shape of starch granules, but granules isolated from germinated mung bean starch exhibited dents surface structure compared with smooth surface of native starch. The molecular weight of starch isolated from germinated mung bean was found to be smaller than that of native ones. Although germinated mung bean showed greater crystallinity than that of native sample, the germination did not change the crystalline structure type of starch (C-type). Moreover, solubility and swelling power of starch varied depending on germination duration and testing temperature. Peak viscosity and trough viscosity slightly decreased as germination prolonged to 72 h. Furthermore, starch isolated from mung bean germinated for 12 h showed greater enthalpy (ΔH) than that of starch isolated from native sample; while, ΔH decrease as germination time prolonged from 36 to 72 h. The obtained results may help in understanding the influence of germination on functional properties of mung bean starch and choosing appropriate applications to promote utilization of mung bean starch in food industry.