New starches. Preparation and properties of starch and its fractions of two varieties of groundnuts

Abstract

The isolation and properties of starch and its fractions from two varieties of groundnuts have been investigated. Starch contents were 13.0 and 18.2% on dry basis of defatted flours. Gelatinization temperatures were 62.0°-66.5°–71.0°C and 63.4°-68.2°-73.2°C and iodine affinities were 5.95 and 6.3 for the two varieties, respectively. Starches from both varieties presented single-staged swelling and solubility behaviour. The amylose content of starch was found to be 30.0% and 28.2%. The molecular weight determinations of amyloses were obtained by gel filtration. The molecular weights of amyloses were approximately 350,000 and 380,000 respectively. The amylopectin fractions from both varieties of groundnuts seem to have molecular weights higher than 20 × 10⁶. Both starches were found to be non-ionic.