The effect of dehulling of yellow peas and faba beans on the distribution of carbohydrates upon dry fractionation

Summary

The impact of dehulling as a pre-treatment for dry fractionation on the distribution of inositol phosphate and the composition and quantity of different carbohydrates in the fine and coarse fractions from yellow peas and faba beans was elucidated. For peas, low molecular weight carbohydrates markedly increased during air classification in the fine fraction whereas for faba beans this tendency was less pronounced. Sucrose and raffinose series oligosaccharides were higher in the coarse and fine fractions, respectively, independently on dehulling pre-treatment. A large part of the insoluble non-starch polysaccharides (NSP) was removed by dehulling and mostly assigned to cellulose. Dehulled faba beans and peas contained similar amount of total and soluble NSP, of which the latter were assigned to pectin and arabinogalactan. In general, dehulling increased the amounts of soluble NSP. Dehulling enriched phytic acid in remaining seeds and it was further enriched with protein in fine fractions. Regarding the aimed product e.g., fine fraction, dehulling gives a slight reduction of non-digestible oligosaccharides and phytic acid in peas but not in faba beans.