LAUSR

Anthocyanins are being explored as natural food colorants thanks to their diverse color portfolio. However, the main challenge for food industry application is their instability and pH-associated color change which occurs in majority of the foods containing natural pigments. Anthocyanin-derived pigments pyranoanthocyanins are being largely investigated as stable natural food colorants, since they are resistant to pH, SO 2 or ascorbic acid. In this study two experimental approaches were compared for the synthesis of pyranoanthocyanin vitisin A and three vinylphenolic pyranoanthocyanins (malvidin-3- O -glucoside-4-vinylcatechol, malvidin-3- O -glucoside-4-vinylphenol, and malvidin-3- O -glucoside-4-vinylguaiacol). Synthesis of pyranoanthocyanins with artificial ageing of model wine solution at 30 °C was compared to the fermentation of model grape must with yeasts. Both model solutions contained Vitis vinifera L. cv. Pinot Noir anthocyanin skin extract. The fermentation with the yeast Pichia guilliermondii ZIM624 showed higher potential for the production of vinylphenolic pyranoanthocyanins in comparison to artificial ageing at 30 °C. The results show a 50-fold higher yield of malvidin-3- O -glucoside-4-vinylphenol obtained by fermentation in comparison to artificial ageing. In contrast, artificial ageing of model wine produced higher yield of vitisin A (21.3%) while fermentation with P. guilliermondii ZIM624 produced this pyranoanthocyanin to a lesser extent (1.1%). The vitisin A yield in fermentations with six other yeast strains was lower than 4%. Produced pyranoanthocyanins were isolated with semi-preparative HPLC–DAD and identified with HPLC–PDA–MS 3 . The color of pyranoanthocyanin methanol fractions ranged from orange to pink, to light purple.