Physicochemical properties of starch extracted from Colocasia esculenta (L.) Schott (Bun-long taro) grown in Hunan, China

Taro (Colocasia esculenta (L.) Schott) starch was extracted from the corms of Bun-long taro cultivated in Hunan, China, and its physicochemical properties were determined and compared with those of potato and sweet potato starches. Bun-long taro starch had an irregular, polygonal shape, and grains were small in size: the surface-average granule diameter ranged from 1.3 to 2.2 mu m. Amylose content in Bun-long taro starch was 8.4 +/- 0.2%, determined by dual-wavelength colorimetry, and the starch had an A-type XRD pattern. The onset temperature (T-o), peak temperature (T-p), and completion temperature of gelatinization (T-c) associated with Bun-long taro starch were 73.6, 80.3, and 88.3 degrees C, respectively, determined by DSC. According to the Brabender amylograph paste viscosity analysis, the viscosity of Bun-long taro starch started increasing at 77 degrees C, which was higher than the temperatures at which the viscosities of potato starch and sweet potato starch started increasing.