Phenolic profile of selected grape (
Vitis vinifera
L.) varieties in the course of ripening and
B
Kim Marie Umberath, Louis Backmann, Maren Scharfenberger‐Schmeer, Pascal Wegmann‐Herr, Andreas Schieber, Fabian Weber Abstract
BACKGROUND
Grapevine phenolic compounds play key roles in plant defense and wine quality. Composition depends on factors such as maturity and infections such as grey mold caused by Botrytis cinerea . Grapevines respond to infections by actively modifying their phenolic profile. These changes, along with fungal enzymes such as laccases, influence the overall phenolic composition. As a result of climate change, incidence and severity of infections are increasing, with different varieties being susceptible to varying degrees. This study examines differences in susceptibility and the impact of ripening and B. cinerea infection on phenolic profiles in three grape varieties over two vintages.
RESULTS
Heavy rainfall following prolonged drought increased the risk of infection. Occurrence of infection varied by sugar content, with Riesling showing higher susceptibility than Pinot noir. Compared to the non‐infested Pinot gris variety, the profile changes primarily involved hydroxycinnamic acids and methoxylated compounds. Flavonols were the only group not affected at all. A myricetin hexoside, which is usually not synthesized by white cultivars, was detectable in infested Riesling. Pinot gris and Pinot noir were characterized by high levels of trihydroxylated polyphenols. Riesling showed decreasing levels of phenolics in early ripening stages and induction only at advanced infection. For Pinot noir, the opposite development was observed.
CONCLUSION
Modifications in phenolic composition can be dependent on cultivar, Botrytis laccase activity and substitution pattern of involved compounds. Trihydroxylated compounds might contribute to resistance. These insights provide a foundation for further targeted studies and grape breeding efforts incorporating phenolic profile as an additional factor for resistance. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.