Exploring the Sustainable Utilization of Agro-Processing Waste for Pectic-Oligosaccharide Production: Characterization and Antioxidant Assessment

This study aimed to extract and characterize the structural properties of pectic-oligosaccharides 
(POS) from various agro-processing waste materials via oxidative degradation using alkaline hydrogen peroxide. Surprisingly, potato peel demonstrated the highest sensitivity to the oxidative process, allowing to produce POS under milder conditions compared to pomelo peel and orange pomace. The structural diversity among POS products derived from different pectin-rich sources became evident. POS originating from orange pomace and potato peel exhibited a notably smaller average molecular size, constituting approximately 50% and 54%, respectively, of species with DP>5. In contrast, pomelo peel yielded the highest POS content at 19% (w/w). Furthermore, POS derived from potato peel exhibited the lowest degree of methylation, nearly approaching zero, whereas those from pomelo peel and orange pomace displayed DM values of 21% and 15%, respectively. To assess their functionality, the antioxidant properties of POS were evaluated through DPPH and ABTS radical scavenging assays. POS obtained from orange pomace and potato peel exhibited exceptional activity, demonstrating IC50 values against DPPH and ABTS of 1.20 and 1.25 mg/mL, and 6.24 and 5.07 mg/mL, respectively. These findings underscore the scalability potential of orange pomace and potato peel for commercial POS production. Moreover, they open avenues for the development of novel functional ingredients with broad applications across the food, pharmaceutical, and biotechnology sectors, offering sustainable.