Pyranoanthocyanins in bilberry (Vaccinium myrtillus L.) wines fermented with Schizosaccharomyces pombe and their evolution during aging.

Fifteen vitisin A-type pyranoanthocyanins (vAPs) were determined in bilberry wines fermented with Saccharomyces cerevisiae and Schizosaccharomyces pombe by HPLC-DAD and UPLC-DAD-ESI-MS/MS. The fermentation involving S. pombe enhanced the production of vAPs compared to the fermentation with pure S. cerevisiae. The formation of vAPs correlated significantly with the decrease in the content of monomeric anthocyanins and pyruvic acid during 12 months of aging. vAPs were more stable than their corresponding monomeric anthocyanins. Methylation in the B-ring and glycosylation with galactose and arabinose further improved the stability of vAPs. Aging for 12 months led to depletion of pyruvic acid and reduction of over 50% of monomeric anthocyanins. The content of vAPs increased by 26-54% during the first six months of aging, followed by a 2.2-10.2% reduction over the following six months. More residual pyruvic acid in S. pombe wines after fermentation consequently enhanced the generation of vAPs during aging.