A study of the intervarietal differences of cotyledon and seed coat carbohydrates in soybeans

A selection of food grade soybean varieties from Canada and Japan, and an e xperimental line which produces a high proportion of 'stone seeds', were se parated into seed coat and cotyledon. Following the removal of oil and prot ein, the samples were fractionated into polysaccharide groups, first by sol ubility in water and then secondly in a scheme using aqueous ethanol, sodiu m carbonate and KOH. The subfractions were hydrolysed using 1 M and 12 M su lfuric acid then analysed by HPLC for monosaccharides and by a colourimetri c method for uronic acids. The results showed that there was very little in tervarietal difference in the carbohydrate composition of the cotyledons bu t there were some significant differences in the seed coat composition. A h igh concentration of xylose was found in the KOH soluble hemicellulose frac tions which was highest in the stone seed sample and lowest in the Japanese varieties. (C) 2000 Elsevier Science Ltd. All rights reserved.