Investigation of antioxidant activity of black-berry and cranberry liqueurs, prepared by the method of ultrasonic extraction

Experimental results of antioxidant activity of berry liqueurs prepared by the method of ultrasonic extraction in comparison with liqueurs, obtained by the traditional method are presented in the article. Blackberries and cranberries, characterized by a high content of antioxidants were chosen as the research subjects. Ultrasonic extraction method with which cranberry and blackberry liqueurs were prepared was studied in terms of the given experimental work. An extractor with submersible ultrasonic transducer was used as an experimental device. The process was carried out in the frequency range of 20 - 20.5 kHz at 20-22о С. In accordance with the traditional technology of preparation of berry liqueur cranberry and blueberry were kept for a long-term (more than 2 months) in 40% ethanol solution at a ratio of berries to extractant of 1: 5. Ultrasonic extraction involves brief contact of berries and extractant (up to 15 minutes) with the application of ultrasonic vibrations. Operating parameters of extraction were determined experimentally in the research process. With the increase in exposure time, the yield of biologically active substances increases to reach an equilibrium state corresponding to the most complete raw materials depletion. The optimum extraction time during which the maximum possible transfer of solids in the extract occurs was determined. Ultrasonic extraction method can significantly reduce the processing time and provide a more complete extraction of substances. Diffusion boundary layer is disrupted, the penetration of the extractant in the material is improved during the application of ultrasonic waves. All this leads to a significant acceleration of transition of the active ingredients from the raw material into extractant and to obtaining a product with antioxidant activity greater than the traditional product by 2 times.