EFFECT OF WAXING AND WRAPPING ON PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF CITRUS DURING STORAGE

The effect of waxing and wrapping on fruit quality, phenolic compounds and antioxidant activity of two citrus cultivars (Satsuma mandarin [Citrus unshiu Marc] and Hamlin orange [Citrus sinensis Osbeck cv Hamlin]) stored at 10 ± 2C for 60 days was investigated. Ascorbic acid, flavanone glycosides, phenolic acids, total phenolics and antioxidant activity (ferric-reducing antioxidant power assay and 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging assay) were determined. During storage, phenolic compounds were relatively stable. Antioxidant activity was influenced by both ascorbic acid and phenolic compounds. Generally, wrapping fruits retained higher levels of flavanones and phenolic acids during storage while waxing was not preferable in preserving phenolic compounds especially after 30 days. Besides, waxing and wrapping retained higher levels of total phenolics after 15 days of storage in both cultivars. PRACTICAL APPLICATIONS Recently, phenolic compounds of citrus fruits have gained much concern because of their benefits to human health. However, studies on changes of detailed phenolic components during postharvest storage are limited. The effect of waxing and wrapping on phenolic compounds and antioxidant activity of Satsuma mandarin (C. unshiu Marc) and Hamlin orange (C. sinensis Osbeck cv Hamlin) during storage are presented in this study. The results show that the two citrus cultivars maintained their functional value because of the stability of phenolic compounds during storage. Wrapping preserved higher levels of phenolic content with improved fruit appearance thus is better for marketing and consumption. While waxing had negative effects on keeping functional quality of fruit after long-time storage. The findings may also be useful for a better understanding of changes in specific phenolic compounds in citrus fruits during postharvest storage.