Evaluation of Atili (Canarium schweinfurthii) fruit oil from different extraction methods for potential use as a natural bio-preservative

This study evaluated the quality indices and antimicrobial activity of oils extracted from Canarium schweinfurthii (Atili fruit) using four methods: soxhlet, conventional extraction (with modification), cold solvent, and cold press oil extraction methods. The soxhlet method produced the highest oil yield (44.72%) and the lowest peroxide value (77.27 meq/kg), indicating greater oxidative stability. The conventional method yielded oil with the lowest acid value (38.15 mg KOH/g) and free fatty acid content (19.17 mg KOH/g). Soxhlet extracted oil had the least density (0.92 g/mL), while cold solvent-extracted oil had the lowest specific gravity (0.94). The antimicrobial properties of the extracted oils were tested against food spoilage and pathogenic microorganisms, including Aspergillus flavus, Penicillium sp., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Saccharomyces sp. using agar-well diffusion and micro-broth dilution methods. The oils demonstrated broad-spectrum antimicrobial activity, with P. aeruginosa showing the least susceptibility and spoilage yeast being the most susceptible. Antibacterial activity was achieved at an average oil concentration of 6.25%, while antifungal effectiveness was sustained at concentrations above 12.50%. These findings highlight the potential of C. schweinfurthii oil, particularly soxhlet-extracted oil, as a natural bio-preservative for fruits and vegetables, providing an environmentally friendly alternative to synthetic preservatives for post-harvest loss reduction.