Determination of mono-, di-, and oligosaccharides in legumes by high-performance liquid chromatography using an amino-bonded silica column

A high-performance liquid chromatography (HPLC) method for soluble sugars analysis, using an [[(aminopropyl)methyl]silyl]-bonded amorphous silica column, was applied to several dry legumes: chickpeas, lentils, white beans, pinto beans, and peas. Monosaccharide (ribose, fructose, glucose, and galactose), disaccharide (sucrose, maltose, and melibiose), and oligosaccharide (raffinose, ciceritol, and stachyose) composition of these samples was analyzed, with special interest on a-galactosides, because of their physiological role in inducing flatulent phenomena in humans after ingestion of legumes. Ciceritol (an inositol digalactoside) was the main sugar in chickpea samples and it was present also in lentils. In all the samples stachyose was found at higher levels than raffinose, and the content of these two flatulence-inducing sugars is higher in beans and lentils and lower in peas and chickpeas. However, great variability has been found in the sugar content of the different samples analyzed, probably due to genetic and environmental factors. The proposed method showed good results for the analysis of 10 simple and complex sugars in legumes, in a final time of about 40 min and in the same chromatographic run.