Sustainable Optimization of Ohmic Heating–Assisted Extraction of Polyphenolics from Goji Berry (Lycium barbarum L.): LC–MS/MS Profiling and Blueness–Greenness Assessment

This study aimed to extract bioactive compounds from goji berry (Lycium barbarum L.) fruit using the ohmic heating–assisted extraction (OHAE) method and optimize the extraction conditions. In this context, firstly, the extraction conditions to be applied for the OHAE method were determined using the response surface method (RSM)-Box Behnken experimental design. During the study, temperature, holding time, and electrical field strength were determined as independent variables, while the total phenolic compound (TPC), total flavonoid compound (TFC), and antioxidant activity (DPPH) were selected as dependent variables. As a result of the optimization, the optimum conditions were determined to be 60 °C for the temperature, 60 min for the holding time, and 45 V/cm for the electrical field strength, and the composite desirability value of the model was 0.90. The highest experimental results for TPC, TFC, and DPPH were found to be 23.83 mg GAE/g, 7.33 mg QE/g, and 24.53 mg TE/g, respectively. In addition, the polyphenolic profiles of all extracts obtained under different process conditions were determined by LC–MS/MS, and rutin was the phenolic detected at the highest rate in the extracts. In addition, the blueness and greenness of the analytical method used in this study were evaluated using the BAGI and ComplexGAPI metrics, respectively. The results indicate that OHAE is an effective and sustainable method for extracting bioactive compounds from goji berries.