Efficacy of essential oils against gray mold and effect on fruit quality during cold storage in table grapes

Abstract

This study investigated the effect of thyme, cinnamon, and oregano essential oil treatment (spraying and fumigation) on gray mold (Botrytis cinerea) and the quality of Taify table grapes in cold storage. Fruit were sprayed with 0.5% and 1% concentrations, fumigated with 2% or 4% concentrations, and stored at 2 °C ± 1 °C for 4 weeks. Compared with the untreated controls, all treatments had a stronger effect on quality maintenance. In addition, spraying was more effective than fumigation. Fruit sprayed with oregano oil with 1% concentration exhibited the least weight loss, decay, infection, and physical damage. They also exhibited the least changes in soluble solid content, vitamin C, and berry coloring. The second most effective treatment was spraying with cinnamon oil with 1% concentration. Furthermore, all treatments reduced the natural occurrence of B. cinerea. The highest reductions were observed in the oregano treatments (spraying with 1% and 4% concentrations). The lowest reductions were observed in the thyme treatments (spraying with 0.5% and 1% concentrations). The lowest levels of peroxidase and polyphenol oxidase enzymes were observed in the treatments with oregano (spraying with 0.5% and 1% concentration) and cinnamon (spraying with 1% concentration). Our results suggest that cinnamon and oregano essential oils could be used as natural antifungal compounds during postharvest storage.