Phenolic Content, Antioxidant Potential, and Antimicrobial Activities of Fruit and Vegetable By-Product Extracts

Abstract

The use of fruit and vegetable by-products as natural food additives has recently been suggested, due to their richness in polyphenols. The aim of this research study was to determine polyphenolic content and the antioxidative and antimicrobial activities of 13 fruit and vegetable by-product extracts obtained with three solvent mixtures. The Folin-Ciocalteu method was employed to calculate the total phenolic content, while antioxidant capacity was assessed with DPPH· and ABTS ·+. The highest total phenolic content and antioxidant capacity values were obtained for the acetonic extracts. Pomegranate peels and hazelnut skins showed the highest values of total phenolic content (212.3 and 166.3 mg GAE/g dw, respectively) and antioxidant capacity (95.7 and 92.9 of inhibition percentage, respectively, for DPPH· assay). The antimicrobial activity against twelve foodborne pathogens and spoilage microorganisms was evaluated. Pomegranate and apple peels showed the highest inhibition of Staphylococcus aureus and Pseudomonas fluorescens. The results obtained demonstrated that by-products could be used as natural food additives with beneficial health properties.