OPTIMIZATION THE EXTRACTION PROCESS FOR DETERMNATION OF FLAVONOIDS AND ANTIOXIDANT CAPACITY FROM SOYBEAN SEEDS

Optimization the extraction process of flavonoids from soybean seeds (Glycine max L.) by response surface methodology (RSM) in conjunction with central composite design (CCD) was performed. The maximum yield of total flavonoids content (TFC) and the 2,2-diphenyl-1-pierylhydrazyl (DPPH) free-radical scavenging potential were used as quality indicators. The extraction was carried out three cycles by using acetone as solvent. The range of the independent variables, namely acetone concentration (60?80%, v/v), the ratio of solvent and material (6:1?10:1, v/w), the extraction temperature (30?50°C) and time for each cycle (180?240 minutes) were identified by a first set of single and two factor experiments. The optimum conditions for extraction were found to be at acetone concentration 69%, the ratio of solvent and material 8:1 (v/w), extraction temperature 42°C and 184 minutes for each cycle extraction. Under these optimized conditions, the experimental yields of TFC and DPPH free-radical scavenging potential were respectively 2.2 ± 0.01 mg QE/g DW and 79.49 ± 0.16% which were in close agreement with predicted values, This indicates the suitability of the models developed and the success of RSM in optimizing the extraction conditions.