Coating Based on PVOH and Starch with Essential Oils of Citronella, Lemongrass, Cinnamon, and Thyme for Preserving Avocado (Persea americana Mill. cv. Hass)

Avocado (Persea americana Mill. cv. Hass) is highly perishable due to its elevated postharvest respiratory activity. This study investigated the efficacy of poly(vinyl alcohol) (PVOH) based edible coatings enriched with starch and essential oils (citronella, lemongrass, cinnamon, or thyme) in preserving avocado quality during cold storage over 29 days. Physicochemical parameters including mass loss, firmness, soluble solids, titratable acidity, ripening ratio, peel color, respiration rate, and fungal incidence were evaluated. PVOH coatings significantly reduced respiration rates and increased acidity, thereby delaying ripening. Incorporation of essential oils further enhanced preservation effects, with PVOH + citronella, PVOH + lemongrass, and PVOH + cinnamon treatments showing superior firmness retention. All essential oil formulations effectively delayed color changes and inhibited microbial growth compared to controls. The combined use of PVOH and essential oils proved particularly effective in maintaining postharvest quality, suggesting their potential as an ecofriendly alternative to conventional preservation methods for extending avocado shelf life while minimizing fungal deterioration.