AUTHOR=Li Jing , Hong Mengnan , Qi Baiyu 

TITLE=Impact of Torulaspora delbrueckii During Fermentation on Aromatic Profile of Vidal Blanc Icewine

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.860128

DOI=10.3389/fmicb.2022.860128

ISSN=1664-302X

ABSTRACT=<p>Non-<italic>Saccharomyces</italic> yeasts usually have a positive effect on improving the diversity of wine aroma and increasing the differentiation of wine products. Among these non-<italic>Saccharomyces</italic> yeast species, <italic>Torulaspora delbrueckii</italic> is often studied and used in winemaking in recent years, but its application in icewine has not been reported yet. In this study, indigenous <italic>T. delbrueckii</italic> strains (TD1 and TD2) and <italic>Saccharomyces cerevisiae</italic> strains (commercial yeast SC1 and indigenous icewine yeast SC2) were sequentially inoculated for icewine fermentations; meanwhile, pure <italic>S. cerevisiae</italic> (SC1 and SC2) fermentations were used as the control; TD1, TD2, and SC2 strains used were screened from spontaneous fermentations of Vidal blanc icewine. The aim was to investigate the effect of <italic>T. delbrueckii</italic> on the aroma complexity of icewine, which is of great significance to the application of <italic>T. delbrueckii</italic> in icewine production. The results showed that <italic>T. delbrueckii</italic> was completely replaced by <italic>S. cerevisiae</italic> at the middle and later fermentative stages in mixed culture fermentations. Compared with the icewine fermented with pure <italic>S. cerevisiae</italic>, mixed culture fermented icewines contained lower acetic acid and ethanol, and higher glycerol. The inoculation of <italic>T. delbrueckii</italic> greatly impacted the levels of several important volatile compounds, and more 2-phenylethyl alcohol, isoamyl acetate, linalool, D-limonene, p-cymene and cineole were produced, and the fruity, flowery, and sweet characteristic was intensified. Moreover, the relevance of strain-specificity within <italic>T. delbrueckii</italic> to aroma compound differences was shown. To our knowledge, this study is the first to investigate the application of <italic>T. delbrueckii</italic> in Vidal blanc icewine fermentation, and volatile aroma compounds in the icewine fermented by <italic>T. delbrueckii</italic> and <italic>S. cerevisiae</italic>.</p>