Determination of hydroxytyrosol produced by winemaking yeasts during alcoholic fermentation using a validated...

Area of Science:

• Enology
• Food Chemistry
• Microbiology

Background:

• Hydroxytyrosol (HT) is a bioactive phenolic compound found in wine.
• The origin of HT in wine, particularly its synthesis by yeast, is not well understood.

Purpose of the Study:

• To investigate the potential of winemaking yeasts to synthesize hydroxytyrosol (HT).
• To identify factors influencing HT production during fermentation, including yeast strain and grape variety.

Main Methods:

• Development and validation of a UHPLC-HRMS method for HT quantification.
• Controlled wine fermentations using various grape varietals and yeast strains (Saccharomyces cerevisiae, Torulaspora delbrueckii).

Main Results:

• Hydroxytyrosol (HT) was identified in the intracellular media of tested yeast strains.
• Saccharomyces cerevisiae strain QA23 demonstrated the highest HT production efficiency.
• Grape variety significantly influenced the final HT concentration in wine.
• Maximum HT concentrations were observed between the fourth and sixth day of fermentation.

Conclusions:

• Winemaking yeasts, such as Saccharomyces cerevisiae and Torulaspora delbrueckii, are capable of synthesizing hydroxytyrosol (HT).
• Yeast strains and grape varietals play crucial roles in determining HT levels in wine.
• This study highlights the significant potential of yeasts in contributing to the hydroxytyrosol content of wine.