Effect of extraction conditions on some physicochemical characteristics of pectins from “Améliorée” and “Mango” mango peels

The extraction of pectins from mango peels can offer a way to upgrade byproducts arising from the processing of these tropical fruits. In this work, several extraction conditions (HCl, or deionised water, or ammonium oxalate) were tested in order to isolate pectins from the peels of two mango varieties (Améliorée and Mango) harvested in Cameroon. After determining uronic acid and neutral sugar contents of mango peels and their alcohol insoluble residues (AIR), extracted pectins were analysed for their uronic acid and neutral sugar contents, their degree of methylation and acetylation, and their average molar mass and intrinsic viscosity. The extraction method was shown to significantly act upon yield (9–32% dry AIR), uronic acid (262–709 mg/g dry weight) and neutral sugar (160–480 mg/g) contents of pectin, their degree of methylation (52–86%) and acetylation (1–8%), their molar mass (245,000–432,000 g/mol), and their intrinsic viscosity (320–1346 mL/g). The physicochemical behaviour of pectins could be influenced thereof. With a good recovery yield, a high average molar mass and intrinsic viscosity and a high degree of methylation, ammonium oxalate-extracted mango pectins present good characteristics to be exploited industrially for their gelling properties.