Saponin-enriched tea tree essential oil nanoemulsion for extending the shelf life of Areca bananas

Postharvest losses of bananas remain a major concern, particularly in tropical regions, where rapid microbial spoilage and quality deterioration severely limit marketability and consumer acceptance. Conventional preservation methods often rely on synthetic chemicals, raising concerns about food safety and sustainability. However, natural bioactive compounds such as tea tree essential oil (TTEO) are limited in direct application due to their poor solubility and stability. To address this gap, the present study developed a stable nanoemulsion of TTEO enriched with saponin (TTEO-Saponin) and evaluated its efficacy in preserving the postharvest quality of Musa × paradisiaca L. var. Areca bananas under ambient storage conditions. The optimized TTEO-Saponin nanoemulsion exhibited a droplet size of 12.23 ± 0.586 nm, a low PDI (0.227 ± 0.070), and a uniform spherical morphology. Antimicrobial assays showed inhibition zones of 12.5 ± 0.2 mm against Escherichia coli and 12.0 ± 0.2 mm against Staphylococcus aureus, with MIC values of 150 μg/mL and 37.5 μg/mL, respectively. Bananas treated with TTEO-Saponin displayed significantly lower weight loss, reduced decay, and suppressed mold growth, extending shelf life by up to 9 days compared with untreated controls. Moreover, antioxidant capacity was maintained throughout storage, contributing to overall fruit quality preservation. These findings demonstrate the novelty and effectiveness of saponin-enriched TTEO nanoemulsions as a natural, eco-friendly strategy for extending banana shelf life and reducing postharvest losses, offering practical potential for sustainable fruit preservation.