2019 Volume 25 Issue 6 Pages 863-869
Anthocyanins and tannins were extracted from the skins of Cabernet Sauvignon (CS) and Muscat Bailey A (MBA) grapes. Insoluble cell wall materials (IC) were prepared from the skin, pulp, and seeds of CS and MBA. The adsorption properties of anthocyanins and tannins by IC were analyzed in a model solution.
In CS, skin IC had the potential to adsorb 12% of skin total anthocyanins, and pulp and seed IC each adsorbed 4%. In MBA, skin IC had the potential to adsorb 20% of skin total anthocyanins, pulp IC, 5%, and seed IC, 3%. In both CS and MBA, skin IC also had the potential to adsorb 30% of skin tannins. In addition, pH (2.5 to5.0) and ethanol concentration (0 to 14%) affected skin tannin adsorption. Anthocyanin adsorption was maximum at pH 3.2 in CS and pH 3.0 in MBA, and minimum at pH 3.6 in CS and pH 3.4 in MBA. Tannin adsorption was maximum at pH 3.3 and minimum at pH 4.2 in both cultivars. On the other hand, both skin anthocyanin and tannin adsorption decreased with increasing ethanol concentration in both MBA and CS. These results suggest that must pH may affect the extraction and adsorption of phenolics.
