Extraction of pectin from Elephant Apple and Pomelo fruit peels: Valorization of fruit waste towards circular economy

Abstract

Citrus fruit peels are used as the primary source for pectin production, effectively transforming fruit waste into a valuable resource and making a significant contribution to fostering a circular economy. This study aimed to extract pectin from locally available citrus fruits such as Elephant Apple, inner peel (IP), and outer peel (OP) of Pomelo. Pectin was extracted using acid hydrolysis and sodium-hexa-meta-phosphate extraction, and its physiochemical properties, including moisture, ash, methoxyl content, equivalent weight, anhydrouronic acid (AUA), and degree of esterification, were analyzed. The sodium-hexa-meta-phosphate method yielded higher average pectin percentages (6.73±3.4%) than the acid hydrolysis technique (3.65±1.36%), with Pomelo IP showing the highest yield (10.84±0.19%), followed by Elephant Apple (6.37±0.10%) and Pomelo OP (2.97±0.11%). The pectin powder from Pomelo IP using the sodium-hexa-meta-phosphate method exhibited low moisture (7.36±0.07%) and ash (3.07±0.06%), high esterification (75.56±0.09%), and satisfactory methoxyl (7.48±0.02%), AUA (56.18±0.05%), and equivalent weight (920.67±3.51mg/mol). The extracted Pomelo peel pectin exhibited favorable physicochemical properties, indicating strong potential for stable storage and efficient gel formation, making Pomelo IP a promising source for pectin extraction.