Physicochemical characterization of mung bean starch

Starch from mung bean (Vigna radiata) was isolated and some of the important characteristics determined The yield of starch was 31.1% on a whole-seed basis. The shape of the starch granule was oval to round to bean shaped, with granules 7-26 mu m in diameter. Scanning electron micrographs revealed the presence of smooth surfaces. The gelatinization temperature range was 58-67-82 degrees C and the enthalpy of gelatinization was 18.5 Jig. The total amylose content was 45.3%, of which 12.1% was complexed by native lipids. The X-ray diffraction pattern was of the 'C' type and the X-ray intensities were much stronger than in other legume starches. The starch exhibited a high swelling factor (43.6 at 95 degrees C) in water The viscoamylographic examination of the starch paste (6% w/v) showed the absence of apeak viscosity, a low 95 degrees C viscosity [200 Brabender units (BU)] an increase in consistency (140 BU) during the holding cycle at 95 degrees C and a set-back of 220 BU. Native granules were readily hydrolyzed by porcine pancreatic alpha-amylase (76.4% in 72 h). Retrogradation of mung bean starch (as measured by changes in syneresis, gel strength, enthalpy and X-ray diffraction intensities) appeared to be more severe than in other legume starches.