ANTIOXIDANT CAPACITY OF OLIVE POMACE AND CITRUS PEELS: NEW STRATEGIES TO IMPROVE QUALITY OF GLUTEN-FREE FOODS

Abstract

INTRODUCTION: In recent years, the rise in celiac disease has led to an increase in the production of gluten-free food products based on maize and rice flours, characterized by a high glycaemic index and a low supply of bioactive compounds, limiting the nutritional benefits. A promising solution is the valorisation of agro-industrial by-products, such as olive pomace and citrus peel, which are rich in polyphenols and natural antioxidants, for the development of healthy gluten-free foods. METHODS: Extracts were obtained from olive pomace and citrus peels, using ethanol/water (80:20% v/v) with and without sonication. After 24 hours, the olive pomace sample was centrifuged. Samples were then evaporated in a Rotavapor for a further 24 hours, after which stock solutions were prepared in PBS. Antioxidant capacity (Ferric ion reducing antioxidant power - FRAP) and polyphenol content (Folin-Ciocalteu), were analysed. RESULTS: Yields for 5 g of samples for each protocol (sonicated and non-sonicated) were ± 110 mg for orange peels, ± 87 mg for lemon peels, and ± 92 mg for olive pomace. FRAP and Folin-Ciocalteu analyses confirmed a high antioxidant capacity and a significant polyphenol content, suggesting a strong bioactive potential. CONCLUSIONS: Preliminary results suggest that these by-products may represent a valuable source of bioactive compounds with potential health benefits. Further studies on intestinal cells (CACO-2) will assess polyphenol absorption and its effect in modulating oxidative stress and inflammatory response. Incorporating these extracts into gluten-free food products could contribute to the improvement of nutritional quality and, at the same, promote sustainability and circular economy.