Combined Application of Gamma-Aminobutyric Acid and Carnauba Wax as Edible Coating on Pomegranates in Cold Storage

Pomegranate is a popular fruit, rich in antioxidants and minerals but sensitive to postharvest storage. The efficiency of 5 and 10 mM γ-Aminobutyric Acid (GABA) combined with 0.5% carnauba wax as edible coating was investigated on extending the cold storage life of pomegranate fruit (Cv. Malas Saveh) after 45 and 90 days. Coatings maintained fruit freshness, inhibited the chilling injury symptoms, reduced peel malondialdehyde formation (minimum of 0.74 nM g-1), reduced loss of aroma/taste, and increased aril antioxidant activity (maximum of 94.9%). Aril anthocyanin content was more stable in 5 mM GABA coated than uncoated fruits. However, the coatings caused more weight loss on 45th day (11.0% in 10 mM GABA and 8.3% in the control). This parameter was similar in coated and uncoated fruits after 90 days. Aril phenolic content in coated fruits was higher on 90th day but not on 45th day (maximum of 0.08 mg.100g-1 in the control on day 45). Aril lightness increased in the control sample on 45th day while coated fruits were more similar to harvest time. After 90 days, the control and treated samples were similar. The color scales (a*, b*, and Chroma) values of peels and arils declined by storage without any significant effects of coatings. Peel and aril Hue did not change by storage time or coatings. Results suggested some benefits of coatings for retaining the postharvest quality of pomegranate fruits.