The effect of preharvest salicylic acid treatment on some quality characteristics of fresh thyme (Origanum onites L.) during cold storage

This study was carried out in Egirdir Fruit Research Institute and Postharvest Physiology laboratory of Horticulture Department of Agriculture Faculty at Isparta University of Applied Sciences in 2021-2022. In the study, the effect of preharvest salicylic acid (SA) treatments on storage life and quality of thyme was investigated. For this purpose, 1.5 mM salicylic acid was applied to thyme plants 10 and 20 days before full bloom. The thyme harvested at full bloom satage was transported immediately to the laboratory. Thyme samples placed in modified atmosphere packages (MAP) were stored at 1°C and 90±5% relative humidity for 25 days in normal atmosphere composition (21% O2 and 0.03% CO2). Some quality analysis (weight loss, leaf color, gas composition in MAP, respiratory rate, ethylene production, sensory evaluation, essential oil content and essential oil components) were performed at 5 day intervals during storage. According to research findings, the better results were obtained from SA treated thymes compared to control samples, in general. Salicylic acid treated thymes gave positive results in terms of respiratinon rate, ethylene production, essential oil content, essential oil component and external appearance. As a result, it was determined that the preharvest SA treatment could be one of the cheapest and most practical methods for delaying quality losses in thyme during storage in MAP.