Investigation of the qualitative and appearance characteristics of Eryngium caeruleum L. based on colorimetric and browning indices in storage conditions

Abstract

The eryngo plant is an herb related to the Apiaceae family with the greatest diversity of species, has a gorgeous taste when eaten as a vegetable, and is traditionally used in folk medicine for its health benefits. The present study was to assess the effects of different drying methods and storage times on the quality and appearance of Eryngium caeruleum. The treatments of this study were drying methods (room temperature (25°C) with proper ventilation, oven temperature 55°C, vacuum oven temperature 55°C, and a microwave with a power of 500 W) and storage times (1, 75, and 150 days). The lowest brightness index and the highest browning index were found in the shade-dried samples kept in the refrigerator for 150 days. In these samples, the numerical values of chlorophyll were lower than others. After 75 days, in the vacuum oven-dried samples, the maximum levels of total phenolics and flavonoids and antioxidant activity were calculated. The colorimetric test showed that the oven-dried samples maintained their green color well. However, the storage decreased the quality of plant samples due to the degradation of chlorophyll. Overall, this study showed that the highest greenness and appearance qualities were found in the samples dried in a vacuum oven at 55°C. It seems that appearance indices can be introduced as an initial and quick step in the qualitative assessment of dried leafy products.