Isolation and Characterization of Soluble Polysaccharides and Insoluble Cell Wall Material of the Pulp from Four Mango (<i>Mangifera indica</i> L.) Cultivars

Abstract

Mature green fruits from monoembryonic (Amélie and Palmer) and polyembryonic (M'Bingue and Tête 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 (∼0.5−0.8%/pulp fresh weight) were essentially highly esterified pectic substances (uronic acids content ∼50−60%; degree of methyl esterification ∼89−97%) and their molecular weights were higher in the polyembryonic cvs. CWM, ∼1%/pulp fresh weight, was mainly built of cellulose (∼20%) and highly esterified pectic substances (uronic acids ∼13−24%; degree of esterification ∼63−73%). Hemicellulosic glucans were more abundant in the monoembryonic (∼9%) than in the polyembryonic (∼4%) cultivars. Keywords: Mango; Mangifera indica L.; cultivars; pulp; soluble polysaccharides; cell wall material