Development of an Electrochemical Method for Tannin Removal from Grape Pomace Extracts

Grape pomace (GP) is a by-product of food industry production rich in polyphenols which is beneficial to the human body. One significant challenge in utilizing grape pomace extracts in food industry is the presence of tannins, which have negative sensory attributes, such as bitterness and astringency. In addition to the bitter taste, the bioavailability of tannins is low. In this study, we developed an electrochemical (EC) method as a green technology to efficiently remove tannins from grape pomace extracts. High-Performance Liquid Chromatography (HPLC) was employed to analyze flavonoids, phenolic acids, and anthocyanins in the grape pomace, both pre- and post-EC treatment. HPLC results demonstrated the effectiveness of the EC method in tannin removal, and this is also comfired by Fourier-Transform Infrared Spectroscopy (FTIR) results. Under optimized conditions (current: 0.15A, NaCl concentration: 1.5 g/L, electrolysis time: 30 minutes, pH: 5.0), the Total Tannin Content (TTC) decreased by 83% following electrochemical treatment.