Cell Wall–Anthocyanin Interactions during Red Wine Fermentation-Like Conditions

The effects of temperature and concentrations of ethanol and anthocyanin on the adsorption and desorption processes of anthocyanin onto cell wall material were investigated. Independent variables included temperatures of 15 and 30°C, model wines with ethanol concentrations of 0 and 15%, and anthocyanin concentrations of 1, 1.5, and 2 g/L. These experiments were conducted in triplicate in bench-top solutions that mimicked a single-berry fermentation environment. Desorption experiments were carried out immediately after completing the adsorption experiments to minimize changes on the cell walls that may have affected the kinetics of the process. Results indicate that more than 90% of anthocyanin adsorption occurred within the first 60 min of interaction with cell wall material. However, desorption appeared to occur much faster; a maximum was reached after 30 min. Temperature and concentrations of ethanol and anthocyanin were found to have a significant effect on both adsorption and desorption kinetics. Results show that phenolic concentration in the final wine not only depends on the amount released from the grapes but also on its interactions with the solids in the fermentor. Additionally, these interactions are dependent on temperature and ethanol concentration.