Prebiotic and Antioxidant Potential of Crude Pectin, Pectic Oligosaccharides, and Polyphenols Derived from Orange Peel

Abstract

This study aims to evaluate the prebiotic potential and antioxidant activity of orange peel, and pectin (OPPec), polyphenol extract (OPPoly), and pectic oligosaccharides (OPPOS) derived from the peel by microwave-assisted extraction, ultrasound-assisted extraction and enzymatic hydrolysis, respectively and assessing their individual ability to support the growth of selected probiotic strains (Limosilactobacillus fermentum NCDC-141 (LF) and Lacticaseibacillus rhamnosus NCDC347 (LGG)) and over selected enteric strains (Enterococcus faecalis (EF) and Escherichia coli (EC)). LF showed the highest growth rate when supplemented with 1% and 2% OPPoly (5.29 and 5.25 log CFU/mL, respectively), whereas LGG exhibited the highest growth rate when supplemented with 2% OPPOS (5.46 log CFU/mL) after a fermentation time of 24 h. The highest prebiotic activity score (PAS) was observed for 2% OPPoly with LGG (1.12) and LF (0.86) against EC. Additionally, OPPoly exhibited the highest antioxidant potential in terms of DPPH inhibition (93.73% and 4.05 mg ascorbic acid equivalent/g), total phenolic content (29.27 mg gallic acid equivalent), and total flavonoid content (10.54 mg quercetin equivalent/g), followed by OPP, OPPec, and OPPOS. FT-IR spectroscopy revealed characteristic chemical groups, while SEM imaging showed morphological variations associated with OPP and its fractions. These results suggest that OPPoly and OPPOS generated from waste by-products from the fruit and vegetable processing industry have the potential to selectively enhance the growth of probiotics compared to commensals, along with being a good source of antioxidants as commercial prebiotics and/or dietary supplements. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.