Effect of different drying methods on some phytochemical traits of Chuchak (Eryngium caeruleum Trautv.)

The post-harvest techniques of medicinal plants such as drying, is very important in their production cycle. The present study was carried out to evaluate the effect of different drying methods on some phytochemical traits of Chuchak in the spring of 2020 based on the completely randomized design with three replications. The chuchak samples were collected in the vegetative stage from the gardens of Noor city, Iran. The drying treatments were shade-drying at room temperature (25±3 °C), sun-drying, oven-drying (45, 55 and 65 °C), vacuum oven-drying (45, 55 and 65 °C), microwave-drying (200, 500 and 800 watts), and fresh samples. The studied traits were moisture content based on fresh and dry weight, drying time and speed, ascorbic acid content, protein content, total carbohydrate content, total phenol and flavonoid content and antioxidant activity. The results of the variance analysis showed the significant effect of drying methods on all studied properties of the samples (P≤0.01). The mean comparison showed that the minimum drying time and the maximum speed drying were related to the microwave (800 watts). The highest amount of ascorbic acid (385.72 µg/mg), protein (19.72%), total phenol (47.19 mg GA per 1 g dry matter), total flavonoids (50.96 mg quercetin per 1 g dry matter) as well as antioxidant activity (76.02%) was observed in the fresh plant and then in the oven-drying (55 °C).