Adsorption/desorption characteristics and separation of anthocyanin compounds from grape wine pele pomace Alicante Bouschet using microporous resins

Grapes are one of the most commonly produced fruit crops in the world. Consequently, the grape industry produces large amount of grape pomace which is a rich source of health promoting polyphenols such as proanthocyanidins, flavones and flavan-3-ols, in this context, there are many types of adsorbents available, but macroporous resins are reported to be the most efficient for polyphenol recovery because of its characteristics such as low cost, high recuperative capacity and long term-validity. Therefore, in this study, the adsorption/desorption characteristics of anthocyanins of grape wine peel pomace Alicante Bouschet (GWPP) on six types of macroporous resins (XAD 2, XAD 4, XAD 7HP, XAD 8, XAD 11 and XAD 16 were investigated. On basis of static adsorption test XAD-7HP and DAX 8 showed higher adsorption/desorption capacities. The adsorption mechanism indicated that the process was better explained by pseudo-first-order kinetics and the Langmuir isotherm model. Adsorption isotherm tests showed that the adsorption process was exothermic on XAD 7HP and DAX 8 when performed at 30° C compared to 40 °C and 50 °C. The results of antioxidant tests indicate that purified anthocyanin extract showed high antioxidant capacity in the both methods of FRAP and DPPH 12.75 and 12.06 mg TE.g-1 respectively. Regarding to high-performance liquid chromatography analysis, the initial and purified extracts were rich in acylated anthocyanins (67.06%) and (71.33%) respectively. Overall, macroporous resins can be an effective tool to purificate anthocyanin instead of using organic solvents, in addition to supply pharmaceutical and food industry with safe and cheap process.