Carbohydrate composition of groundnuts (Arachis hypogea)

Abstract

The proximate composition of defatted edible groundnut flour, processed and unprocessed, has been determined. The flour contains about 38% total carbohydrates of which oligosaccharides account for 18%, starch 12.5%, hemicelluloses A and B 0.5 and 3.5% respectively and fibre (cellulose) 4.5%. Sucrose 13.90 and 14.55%, raffinose 0.89 and 0.92%, stachyose 1.56 and 1.60%, and verbascose 0.41 and 0.42% represent the oligosaccharide fractions (from 70% alcoholic extract) of unprocessed and processed flour, respectively. In addition the unprocessed flour also contained glucose 0.80% and fructose 0.41 % along with two unidentified spots 0.70%. Hemicellulose A consisted of glucose, arabinose, and xylose (4:0.5:0.1) whereas hemicellulose B had galacturonic acid, glucose, galactose, arabinose and xylose (1:4:1:12:6). The fibre fraction on hydrolysis yielded predominantly glucose with only traces of galacturonic acid and rhamnose. The presence of verbascose and xylose in groundnuts has not been previously reported.