Enhancing post-harvest shelf life of guava (Psidium guajava L.) using herbal coating enriched with Allium cepa green leaves

Post-harvest losses of guava, a nutritionally rich tropical fruit, are significant due to its rapid ripening and short shelf life. This study explores the efficacy of herbal edible coatings derived from Allium cepa (Onion) green leaves in extending the shelf life and maintaining the quality of guavas stored at room temperature over a 10-day period. Coating solutions were formulated with varying concentrations of Allium cepa green leaves (2%, 4%, and 6%) combined with corn starch, guar gum, glycerol and psyllium husk, namely as T1, T2, and T3 respectively. Fresh guavas were uniformly coated by dipping and subsequently air-dried before storage. Quality parameters assessed included visual color and appearance, weight loss, physiological loss in weight (PLW), total soluble solids (TSS), microbial load (Total Plate Count), and sensory attributes evaluated by a trained panel using a 9-point hedonic scale. Results indicated that guavas coated with the T3 formulation exhibited significantly lower weight loss and PLW (11%) compared to uncoated controls (12.5%) over the storage period. The T3 coating also effectively maintained color and appearance, delaying noticeable browning and microbial growth observed in uncoated samples. Additionally, T3-coated guavas showed controlled TSS levels, suggesting a slowed ripening process. Microbial analysis revealed that T3 significantly reduced the total plate count to 6.0 × 10³ CFU/g, compared to 1.2 × 10⁴ CFU/g in uncoated fruits. Sensory evaluation highlighted superior scores for T3 in color, appearance, firmness, flavor, and overall acceptability, indicating enhanced consumer acceptability. The T3 herbal coating containing 6% Allium cepa green leaves effectively preserves the physicochemical and sensory quality of guavas during storage, demonstrating its potential as a natural and sustainable method to extend the shelf life of perishable fruits. This approach not only reduces post-harvest losses but also offers a consumer-friendly preservative alternative, contributing to better marketability and reduced environmental impact.