Effect of fermentation, postfermentation, and postbottling heat treatment on Cabernet Sauvignon glycoconjugates

In Cabernet Sauvignon must, total and phenol-free glycosides (expressed as glycosyl-glucose) rose during fermentation while skin concentrations dropped. Wines were heated postfermentation, prior to dejuicing (rising 2 to 3degreesC per day from 23 to 42degreesC, and held for one day at 42degreesC), or after bottling (at 42degreesC for 21 days) to determine the effect on total glycosides, glycosidic fractions, and anthocyanin complexing. Pre-dejuicing thermal vinification resulted in higher total (12%) and phenol-free (18%) glycosides. Large polymeric pigments rose 208% and small polymeric pigments rose 41%. Skins had lower total glycosides (-16%), and no significant difference in phenol-free glycosides. Postbottling heat treatment resulted in lower total (-15%) and phenol-free (-16%) glycosides, and increased hue (25%). Large polymeric pigments increased 62% compared to control wines.