ISOLATION AND CHARACTERIZATION OF SOLUBLE POLYSACCHARIDES AND INSOLUBLE CELL WALL MATERIAL OF THE PULP FROM FOUR MANGO (MANGIFERA INDICA L) CULTIVARS

摘要

Mature green fruits from monoembryonic (Amelie and Palmer) and polyembryonic (M'Bingue and Tete de Chat) mango cultivars were initiated to ripen with ethylene (10 ppm, 24 h) and then left to reach full ripeness (6 days). After elimination of skin and kernel, pulp was added with HEPES (1/5, w/w) and centrifuged. Soluble polysaccharides were obtained from the supernatant by precipitation with ethanol and freeze-drying. Cell wall material (CWM) was isolated from the pellet by the buffered phenol procedure and further enzymatically destarched. Soluble polysaccharides (similar to 0.5-0.8%/pulp fresh weight) were essentially highly esterified pectic substances (uronic acids content similar to 50-60%; degree of methyl esterification similar to 89-97%) and their molecular weights were higher in the polyembryonic cvs. CWM, similar to 1%/pulp fresh weight, was mainly built of cellulose (similar to 20%) and highly esterified pectic substances (uronic acids similar to 13-24%; degree of esterification similar to 63-73%). Hemicellulosic glucans were more abundant in the monoembryonic (similar to 9%) than in the polyembryonic (similar to 4%) cultivars.