PT  - JOURNAL ARTICLE
AU  - Sabrina Zimdars
AU  - Rita Caspers-Weiffenbach
AU  - Pascal Wegmann-Herr
AU  - Fabian Weber
TI  - Stilbenes Can Impair Malolactic Fermentation with Strains of <em>Oenococcus oeni</em> and <em>Lactobacillus plantarum</em>
AID  - 10.5344/ajev.2020.20021
DP  - 2021 Jan 01
TA  - American Journal of Enology and Viticulture
PG  - 56--63
VI  - 72
IP  - 1
4099  - http://www.ajevonline.org/content/72/1/56.short
4100  - http://www.ajevonline.org/content/72/1/56.full
SO  - Am J Enol Vitic.2021 Jan 01; 72
AB  - Malolactic fermentation (MLF) is an important step in winemaking to improve wine quality by deacidification, increased microbial stability, and modified wine flavor. The phenolic composition of the wine influences the growth and metabolism of the lactic acid bacteria (LAB) used for MLF. Due to increased cultivation of fungus-resistant grape cultivars, the present study aimed to analyze the influence of stilbenes on MLF because stilbenes play an important role as phytoalexins in plants to counteract fungal pathogens. The analysis showed that the grapevine-shoot extract Vineatrol and the stilbenes ε-viniferin, ampelopsin A, r2-viniferin, and r-viniferin, as well as mixtures of the five stilbenes, decelerated malic acid degradation. This can be partially attributed to a reduced number of viable cells. However, the direct impact of stilbenes on the malolactic enzyme must also play a role, as shown by the finding that the viability of LAB stabilized, while at the same time, malic acid degradation was reduced. These results show that wines made from stilbene-rich grapes, such as fungus-resistant cultivars, might have a higher risk for a sluggish or incomplete MLF.