Bioactive compounds recovery optimization from vine pruning residues using conventional heating and microwave-assisted extraction methods

Polyphenol compounds from vine pruning residue (VPR) were extracted by conventional heating and microwave-assisted treatments. For each treatment, total phenolic compounds and their antioxidant activity were optimized by experimental design. Maximal extraction of polyphenolic compounds (2.17 g/100 g VPR) was obtained at 80 degrees C, 120 min and 45% of ethanol by conventional heating, and 2.37 g/100 g of VPR were extracted by microwave-assisted process at 120 degrees C, 5 min and 60% of ethanol. Ellagic acid and apigenin were the predominant polyphenolic compounds in the extracts, achieving concentration of 68.65 and 208.23 mg/100 g VPR, respectively for conventional heating and 185.15 and 118.84 mg/100 g of VPR for microwave-assisted treatment. The results showed reduction of extraction time and energy consumption for microwave-assisted treatment leading to cost-effective technology for the extraction of polyphenol compounds. Furthermore, the results hereby compiled allow for the tailor-made extraction of specific high-value compounds from a renewable biomass as vine pruning residue.