POLYSACCHARIDES FROM THE CELL-WALLS OF PINEAPPLE FRUIT

Cell wall material from pineapple fruit was obtained and sequentially extracted with 50 mM NaOH at 2 degrees C, 1 M KOH at 2 and 20 degrees C, and 4 M KOH at 20 degrees C. From the 4 M KOH-soluble fraction, a ''neutral'' polysaccharide and an acidic one were isolated by chloride anion exchange chromatography. The ''neutral'' fraction was composed of xylose, arabinose, glucose, galactose, and minor quantities of mannose. The infrared spectra showed an absorption band at 900 cm(-1) of beta-linked polysaccharides. The methylation analysis revealed the main glycosidic linkages of the ''neutral'' polysaccharide: 1,4-linked xylose with branching points in C-3 and C-2, 1,4-linked glucopyranose with branching points in C-6, and terminal glucopyranosyl, arabinofuranosyl, and arabino/xylopyranosyl residues.