Mango pectin quality as influenced by cultivar, ripeness, peel particle size, blanching, drying, and irradiation

Abstract

Industrial recovery and application of valuable mango (Mangifera indica L.) peel constituents, such as dietary fiber and pectins, require the conversion of the yet under-utilized and highly perishable by-product into a stable commodity. Focusing on efficient pectin recovery, the impact of different cultivars and ripeness degrees as well as various technological procedures on pectin quality by affecting pectin yield, molecular size distribution of pectic polymers, galacturonic acid content, degree of esterification, and content of interfering substances was analyzed. Cultivar and ripeness degree revealed a significant effect on pectin quality. Preservation processes, i.e. oven drying and lyophilization each with and without previous blanching of integral fruits as well as gamma irradiation, notably influenced the quality of the obtained pectin. Blanching prior to drying reduced arabinogalactan and ash impurities, whereas galacturonic acid contents were increased. Most importantly, grinding of dried mango peels to obtain a particle size of ca. 42 μm (d43) significantly enhanced both extraction yield (+70%) and galacturonic acid content (+20%) without increasing the contents of the above mentioned impurities as compared to a peel particle size of ≥10 mm. Mango pectin produced from such peel powders with a small particle size (≤120 μm) improved breaking and sugar binding capacities as well as gelling units (up to 5476 GU). The production of mango peel pectin and its applications were favored by implementing the proposed procedures into the valorization cascade of mango peels.