Oligosaccharides in Eleven Legumes and Their Air‐Classified Protein and Starch Fractions

Abstract

ABSTRACT Oligosaccharide compositions of flours from dehulled seeds of eleven legumes were determined by gas‐liquid chromatography and mass spectroscopy. While soybean contained 11.7% sugars, concentrations in lupine, cowpea, chickpea and lentil were about 8%; lima, navy and northern beans, field pea, mung bean and fababean contained about 5% of sugars. Sucrose represented 20–55% of the total sugars; stachyose was the principal α‐galactoside in most species. In addition, high amounts of manninotriose were found in chickpea and lentil flours whereas verbascose was a major component in field pea, mung bean and fababean flours. The nine species and biotypes which contained starch were pin milled and air‐classified into protein‐rich and starch‐rich fractions. The protein fractions were 40–90% higher than the flours in α‐galactosides, especially raffinose, manninotriose, stachyose and verbascose. The starch fractions were depleted in α‐galactosides, the concentrations varied from 1.2–2.8% of the fraction.