NONSTARCH POLYSACCHARIDES FROM SUNFLOWER (HELIANTHUS-ANNUUS) MEAL AND PALM-KERNEL (ELAEIS-GUINEENSIS) MEAL INVESTIGATION OF THE STRUCTURE OF MAJOR POLYSACCHARIDES

For the identification and characterisation of major non-starch polysaccharides from sunflower (Helianthus annuus L) meal and palm-kernel (Elaeis guineensis Jacq) meal, extracts obtained by sequential alkaline extraction and delignification of the corresponding cell wall materials were subfractionated by graded ethanol precipitation and size-exclusion and adsorption chromatography. Determination of the sugar and glycosidic linkage composition of extracts and subfractions and intact cell wall materials allowed the identification and quantification of a variety of polysaccharides. In sunflower meal, cellulose (42 % of total non-starch polysaccharides), pectic polysaccharides (24 %), (4-O-methyl)-glucuronoxylans with 8-11 % uronic acid substitution (24 %), (gluco)mannans (5 %) and fucoxyloglucans (4.5 %) were encountered. Major polysaccharides in palm-kernel meal were linear mannans with very low galactose substitution (78 % of total non-starch polysaccharides), followed by cellulose (12 %) and small amounts of (4-O-methyl)-glucuronoxylans and arabinoxylans (3 % each).