OPTIMIZATION OF CONDITIONS FOR OBTAINING URTICA DIOICA L. EXTRACT AND THE STUDY OF ITS ANTIOXIDANT PROPERTIES

Abstract

The purpose of the presented study was to select optimal conditions and develop a technology for obtaining nettle extract, which in the future can be used in food technologies. Nettles were harvested in May before the appearance of inflorescences. The place where the plant is collected is a forest near the village of Lvovka in the Shigonsky district of the Samara region. Mathematical optimization of the conditions for obtaining water-alcohol extract of nettle dioecious was carried out. Nettle extraction was carried out in the traditional way, with ultrasound treatment and ultrahigh frequency currents. To obtain an extract with the highest yield of extractives, it is recommended to use 75% ethyl alcohol as an extractant at a hydromodule of 1 : 10, a temperature in the range from 45 to 55 °C, and an extraction time of 2 hours. In addition, it is possible to use ultrasonic radiation or microwave processing to obtain the extract, which also contribute to an increase in the yield of dry substances. Nettle extract, prepared with the help of ultrahigh frequency currents, showed the greatest antioxidant activity. This extract contains 1309.9 mg of gallic acid and 322.9 mg of catechin per 100 g of feedstock, and its antioxidant activity is 2.5 mg/ml. At the same time, with the help of a microwave field, the extract can be obtained in a minimum time.