Photo-oxidative stress and light-struck defect in Corvina rosé wines: influence of yeast nutritional strategies

Abstract

Light exposure is one of the major factors affecting the sensory quality of rosé wines and resulting in the light-struck fault. The photochemical reaction between methionine and riboflavin leads to the light-struck fault resulting in volatile sulfur compounds such as methanethiol (MeSH) and dimethyl disulfide (DMDS) that are responsible for off-odors with descriptors of onion and cooked cabbage (Fracassetti et al., 2021).

The study investigates the chemical processes that lead to modifications of the volatile chemical profile of Corvina-based rosé wines following light exposure, with a particular focus on the role of yeast nitrogen nutrition.

The study tested seven different nitrogen supplementations: a control (no nutrients), inorganic nitrogen (DAP), organic nitrogen sources (Organic and Organic+Methionine), and combinations of organic and inorganic nitrogen (Mix).

The wines were produced in laboratory scale, all fermentations were carried out in triplicate, in 3 L volumes, at a temperature of 16°C.

After fermentation, the wines were divided into two groups. The first group was bottled into amber bottles then stored in the dark at 16°C temperature for 30 days. The second group was bottled in flint bottles and stored under direct exposure to light for 30 days at a temperature of 16°C.

Volatile compounds were analyzed by the mean of HS-SPME-GC-MS techniques. In total 38 volatile compounds were analyzed belonging to different biochemical classes such as volatile sulfur compounds, esters, fatty acids, alcohols, C₆ alcohols, terpenes, norisoprenoids, benzenoids.

The results showed that light exposure decreased esters, terpenes (linalool, α-terpineol), and norisoprenoids (β-damascenone) while concurrently raising the amount of sulfur compounds linked to light struck defect, like MeSH, DMDS, DMTS.

Finally, a sorting task was conducted to evaluate olfactory similarities among the samples subjected to the nitrogen supplementation after light exposure. It showed that organic nitrogen nutrition strategies clustered together, exhibiting increased attributes of cooked vegetables. These wines showed higher concentrations of sulfur compounds (DMDS, DMTS, MeSH) and a lower content of fruity and floral volatile compounds (α-terpineol, β-damascenone) compared to those in the other cluster, which included the other nitrogen nutrition combinations.

These findings highlighted the importance of nitrogen supplementation sources and management and suitable packaging choices to mitigate the occurrence of light-struck fault in rosé wines, according to the insurgence of faults over the supply chain (Carlin et al., 2022; Fracassetti et al., 2017).

References

Fracassetti, D., Di Canito, A., Bodon, R., Messina, N., Vigentini, I., Foschino, R., & Tirelli, A. (2021). Light-struck taste in white wine: Reaction mechanisms, preventive strategies and future perspectives to preserve wine quality. In Trends in Food Science and Technology (Vol. 112, pp. 547–558). Elsevier Ltd. https://doi.org/10.1016/j.tifs.2021.04.013

Fracassetti, D., Gabrielli, M., Encinas, J., Manara, M., Pellegrino, I., & Tirelli, A. (2017). Approaches to prevent the light-struck taste in white wine. Australian Journal of Grape and Wine Research, 23(3), 329–333. https://doi.org/10.1111/ajgw.12295

Carlin, S., Mattivi, F., Durantini, V., Dalledonne, S., & Arapitsas, P. (2022). Flint glass bottles cause white wine aroma identity degradation. https://doi.org/10.1073/pnas.