The finger lime (Citrus australasica), an indigenous citrus fruit native to Australia, is rich in bioactive compounds such as phenolics with strong antioxidant properties. Although often considered an agro-industrial byproduct, its peel contains substantially higher levels of phenolic compounds and antioxidant capacity than the pulp. In this study, peels from three finger lime varieties (pink, red, and green) and pulp from the red Champagne variety were freeze-dried and used to obtain antioxidant extracts through ultrasound-assisted extraction (UAE) employing 50% ethanol as solvent. The total phenolic content (TPC) was quantified, and optimal extraction conditions were determined as 30% amplitude, a solid-to-liquid ratio of 1:40, and a 5-minute treatment, yielding TPC values exceeding 300 mg GAE/sample. The optimized extract was incorporated into starch-based biopolymer films to develop active food packaging. Starch was selected due to its low cost, non-toxicity, and ease of processing, while glycerol served as a plasticizer to enhance flexibility. Films containing different concentrations of finger lime extract (5–20%) were produced and evaluated for their physicochemical, mechanical, and optical properties. Additionally, the films were characterized for biodegradability, antioxidant activity, and total phenolic content. The formulation showing the most promising antioxidant performance was further tested for its ability to delay lipid oxidation in soybean oil samples. Overall, the incorporation of finger lime extracts into starch-based films demonstrates strong potential for developing biodegradable active packaging materials with significant antioxidant functionality, contributing to more sustainable food preservation systems.

This poster qualifies for consideration for the Elsevier Competition