Effect of Thymus essential oil in both immersion and fumigant methods on some of the qualitative characteristics of Fakhri cultivar grapes during storage

The use of chemical compounds to prevent corruption and increase the shelf life of agricultural products, including grapes, has many applications. Due to the harmful effects of these compounds on human health and also the tendency of people to use organic products, today the use of low-risk and alternative methods has increased. The use of antimicrobial, antibacterial and antifungal compounds, such as natural essential oils, can be a good way to increase the shelf life of crops. In this study, the effect of thyme essential oil on increasing the shelf life of Fakhri cultivar grapes by two methods of immersion (direct contact) and fumigant (indirect contact) in concentrations (0, 150, 300 and 450 μl / l) In the cold storage with a temperature of 1±2° C and a relative humidity of 90% was tested for 60 days. Traits such as percentage of changes in fruit weight, titratable acidity, total soluble solids, sensory evaluation including fruit texture firmness, Smell and flavor, antioxidant capacity and browning of cluster wood were evaluated. The least percentage of changes in fruit weight and titratable acidity were observed at a concentration of 450 μl /l of thyme essential oil. The control treatment had the highest amount of total soluble solids in fruits (25.2 degrees Brix). Also, the results of sensory evaluation of fruit texture firmness showed that the fumigant method was better than the immersion method with gradual release of essential oil to maintain the firmness of fruit texture better. Sensory evaluation of grape fruit Smell and flavor and taste showed that at high concentrations of essential oil, the sensory evaluation index was lower. Antioxidant capacity was declining in the whole process and fumigant and immersion methods were not significantly different from each other.