CHANGES IN THE COMPOSITION OF STARCH, PECTINS AND HEMICELLULOSES DURING THE RIPENING STAGE OF MANGO (Mangifera indica cv. KENT)

Changes in some polysaccharides during postharvest ripening of ‘Kent’ mangoes were evaluated in the present study. Fruit at physiologi-cal maturity stage were stored to simulate marketing conditions (20 ± 2 °C, 85 % relative humidity) until reaching the ripening stages 2, 3, 4 and 5 (according to the standards of Empacadoras de Mango de Exportación, A. C.). Changes in firmness, starch, pectin, hemicellulose and cellulose were determined. Polysaccharides were obtained from the alcohol-insoluble fractionof the mango flesh. Fruit showed a total firmness loss of 93 % from the ripening stage 2 to 5, which was progressively reduced in 40, 44 and 9 % when the fruit reached the stages 3, 4, and 5, respectively. In that order, the rate of softening was defined as initial, intermediate, and late. During the initial fruit softening, the content of starch was reduced by 90 % and the total sugars by 44 %, while the total uronic acids increased by 39 %. The total concen-tration of arabinose was maintained without significant changes in the different ripening stages at levels of 250 mg·100 g-1 fresh weight; however, a reduction of 50 % in glucose and galactose occurred during the initial softening. The water soluble-fraction was the prevalent pectin fraction with a composition near to 2:1 in the uronide:sugar ratio. During the softening of ‘Kent’ mangoes, changes in solubility and polymerization degree of pectin and hemicellulosic polysaccharides were observed.