Groundnut carbohydrates - a review

Abstract

This review summarises comparative studies conducted here and elsewhere on the various carbohydrate fractions of groundnut. Mono- and oligosaccharides, starch, xylan, glucomannan and cellulose were some of the fractions isolated and characterised. The xylan was shown to be highly branched, having a backbone of β-1,4-linked D-xylopyranose residues and further substituted at C-2 (9.6%) and C-2, C-3 (15.6%). The glucomannan, containing more of glucose than mannose (mol ratio, 4:1) was a linear β-1,4-linked polymer. Investigations using scanning electron microscope of enzymically digested groundnut starch revealed several types of 'pitting' on the starch granular surface. The effects of processing and germination on the make up of groundnut carbohydrates were also investigated. Incubation of the defatted groundnut flour (GNF) with a partially purified hemicellulase preparation indicated almost complete breakdown of the pentosan constituents and resulted in a greater extraction (over 90%) of proteins from GNF.