Some Properties of Sorghum Starches

Abstract

Starch granules were prepared from sorghum (Sorghum bicolor (L.) Moench) grains which were collected in Japan, Korea and Indonesia. Properties of starches, i.e. iodine absorption spectra, distribution of isoamylase-debranched materials, X-ray diffraction patterns, gelatinization characteristics by photopastegraphy and differential scanning calorimetry, and starch-granule susceptibility to amylases were investigated. The results obtained were as follows: 1) Four samples collected in Japan and five ones collected in Korea had waxy-type starches, two samples of Korea (K-6 and K-7) and a sample of Indonesia (I-1) had nonwaxy-type. 2) The nonwaxy type starches, K-7, K-6 and I-1, contained approximately 14, 19 and 24% amylose, respectively. 3) Waxy-type starches had higher gelatinization temperature than those of nonwaxy-type starches, starches of Korean samples tended to have larger heat of gelatinization. 4) Low gelatinization temperature and characteristics of amylopectin in the I-1 starch was supposed to be influenced by a sugary gene. 5) All starches had A-type patterns of X-ray diffractograms. 6) Starch-granules of both waxy and nonwaxy sorghum had higher susceptibility values to amylases comparing with those of normal maize starch-granules.