Optimization of the green extraction process of antioxidants derived from grape pomace

The wine industry generates a large amount of waste, such as grape pomace, which contains compounds of interest. In this study, the ecological technologies of ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE) were investigated to recover compounds of interest from the grape by-product. A fractional factorial design was used to explore the best extraction conditions and Box-Behnken response surface (MSR) methodology was performed for optimization using water as solvent. The best extraction conditions (time: 15 min, temperature: 65 °C, and amplitude: 70 %) resulted in the highest concentrations of phenolic compounds, anthocyanins, and antioxidant activity by the ABTS and DPPH assay. These two green technologies, ultrasound and microwaves and water as the solvent, applying a statistical optimization model allowed to improve extraction yield sustainably to find the best extraction conditions. The compounds extracted have the potential to be used in the food industry.