Isolation and Characterization of Pectin from African Star Apple (Chrysophyllum albidum) Fruit

Pectin was isolated from the African star apple (ASA) (Chrysophyllum albidum) fruit at a fully ripe stage from two geographical zones in Ghana. The study employed Box-Behnken design to determine the effects of extraction conditions, time (30–90 min), temperature (70-90^oC), and pH (2.5–3.5) on yield, degree of esterification and uronic acid content of the pectin extracts. The optimal conditions of the design (90^oC for 60 min at a pH of 2.5) predicted a yield of ~ 11%, with a degree of esterification of 65% and uronic acid content of 75%, which were similar to the experimental values of yield (8.5–10.6%), degree of esterification (DE) (66.8–67.1%) and uronic acid (UA) content (74.5–76.2%). The ASA pectin extracted were characterized in comparison with commercial citrus pectin based on their physicochemical properties. The emulsification capacity of the pectin revealed higher emulsion stability, closely related to commercial citrus pectin. FT-IR analysis of the pectin revealed the presence of a polygalacturonic acid in both samples. The study confirmed that commercial citrus pectin and the citric acid extracted pectin from ASA had comparable characteristics and could be utilized as an alternative extraction source.