Il difetto di luce nel vino bianco : Effetto ed evoluzione nel corso della conservazione = The light-struck taste in white wine : Effect and evolution during the storage

The light exposure of white wine has a detrimental impact on its sensory characteristics. In these conditions, a fault, known as light-struck taste, can appear due to the formation of sulfur compounds, namely methane thiol (MeSH) and dimethyl disulfide (DMDS). The occurrence of photo-induced reactions is strictly related to the presence of riboflavin (RF), a photosensitive compound, and methionine (MET).Wine treatment with bentonite or active charcoal is effective for RF removal, as well as the addition of wood tannins effectively limits the appearance of the defect in model wine. However, the evolution of this fault is not clear during the shelf-life of white wine. In this research, the effects of a light treatment were evaluated in white wine added with RF, MET and antioxidants including sulfur dioxide, glutathione and chestnut tannins, as single or combined addition, and exposed to light followed by the storage in the dark, after 24 months of storage. As expected, the light induced the degradation of RF in all the conditions assayed. MET also decreased by 21–38% depending on the antioxidants added. The investigated antioxidants limited the formation of lightstruck taste as lower amounts of MeSH and DMDS were found when the antioxidants were used singularly. Our data suggest the hydrolysable tannins can be an effective tool to prevent the appearance of light-struck taste in white wine.