Extraction of Anthocyanins from Red Cabbage by Ultrasonic and Conventional Methods: Optimization and Evaluation

The objective of this study was to investigate the optimization of conventional extraction (CE) and ultrasonic extraction (UE) conditions of red cabbage (Brassica oleracea L. var. capitata f. rubra) anthocyanins using response surface methodology. The results showed that the highest anthocyanin content of red cabbage anthocyanin extracts was obtained at 40C, with an extraction time of 75 min and ethanol concentration of 42.39% at a fixed solid–liquid ratio (1:3 w/v) for CE and UE. However, it has been determined that ultrasonic application provides 11.92% more anthocyanin extraction in comparison with CE. Thus, anthocyanin degradation that occurs due to high temperature application can be prevented and extraction can be carried out in one stage extraction using less solvent. In conclusion, it has been determined that ultrasonic application is superior to conventional application when used in moderate conditions (temperature-solvent concentration) for anthocyanin extraction purposes. Practical Applications Nowadays, studies on extraction of anthocyanins from fruit and vegetables that contain high amounts of anthocyanins and utilization of these extracts in food industry are of interest. Extraction of anthocyanins is time-consuming and inefficient, and higher extraction temperatures cause the degradation of anthocyanins. Therefore, it is a key focus to develop new extraction methods with faster extraction rates and higher yields in anthocyanin extraction. The results are important for the effectiveness of the ultrasonic extraction method and the optimized conditions could be successfully employed by the nutraceutical and food industry to extract anthocyanins from red cabbage. Extraction can be carried out in a single extraction step by using less solvent and it will have significant contributions, especially for industrial applications.