IMPROVING POSTHARVEST QUALITY OF TABLE GRAPE CV. "RISH BABA" USING THYMUS KOTSCHYANUS AND CARUM COPTICUM ESSENTIAL OILS

ABSTRACT The antifungal activity of different concentrations of Thymus kotschyanus and Carum copticum essential oils (0, 100, 200, 300, 400 and 500 µL/L) on mycelial growth of Botrytis cinerea and Penicillium digitatum under in vitro condition were investigated. Also, the preservative property of various concentrations of these essential oils (0, 250 and 500 µL/L) to maintenance quality parameters of “Rish Baba” table grape were studied. Chemical compositions of the essential oils were also determined by gas chromatography–mass spectrometry analysis. Major compounds found in essential oils from T. kotschyanus and C. copticum were carvacrol (28.54%) and thymol (63.18%), respectively. The results of in vitro assay showed that T. kotschyanus and C. copticum essential oils in 300–500 µL/L concentration completely inhibited the mycelial growth of B. cinerea and P. digitatum. Also, at the end of the storage period, all the applied concentration of essential oils reduced disease severity compared to control fruit. The application of essential oil did not affect the berry shrinkage and rachis browning. However, essential oil treatment showed high preservative effect on weight loss, appearance, flavor, berry browning, total soluble solids (TSS), titrable acidity (TA) and TSS/TA of treated fruits. Therefore, essential oils may be used as an alternative for the synthetic chemicals for control of postharvest phytopathogenic fungi, and in turn to fulfill consumer requirements for more natural and healthy fruits. PRACTICAL APPLICATIONS Postharvest disease of perishable fruits such as table grape renders heavy losses during transit and storage. Use of chemical fungicides such as SO2 generator pads are basic means of controlling postharvest diseases of table grape. Public awareness about chemical residues in food and interest to use of organic crops intended search to find a new safe alternatives to synthetic fungicides. The main reason for examine the possibility use of essential oils are they plant origins, safe, no side‐effect and their acceptability for consumers. Consequently, recently the interest to use of essential oils to preserve of fruits and vegetables has increased. The goal of this research was to examine the possibility use of T. kotschyanus, C. copticum essential oils to maintain postharvest quality of table grapes.