ON THE PECTIC SUBSTANCES OF MANGO FRUITS

Peels and fruit pulp of two Guinean mango varieties (Ceni and Springfield) were studied. The polyuronide content of the dried fruit material varied from 14.6 to 21.3% depending on the type of raw material (variety and part of the fruit) and methods of treatment prior to drying. By hydrochloric acid extraction at 85-degrees-C and pH = 1.5, the pectic substances were extracted most fully from the dried mango peels (Ceni, 24.5% and Springfield, 22.3%) and least fully from the fleshy part of ordinary mango (Ceni, 5.8%). The molecular mass of the pectins obtained ranged from 72 000 to 83 000 and the gel strength was between 162 and 232-degrees according to Tarr-Baker. The content of bound amino acids in the pectic preparations obtained was in the 1-7% range and did not depend on the degree of esterification of pectin. The carbohydrate composition of the pectins obtained was estimated to be in the following ranges: galacturonic acid (40-70%); arabinose (2-4%); rhamnose (1-2%); xylose (1-7%); mannose (1-3%); galactose (14-22%) and glucose (8-22%).