Abstract:It is known to all that noble-rot wine, a sweet wine made from botrytized grapes, has high cost for its special flavor. Aromas of sweet wines made from artificially botrytized grapes and botrytized juice were studied to evaluate the winemaking process of botrytized wines. Normally harvested Vitis vinifera Var. Ecolly grape was obtained in Yangling, Shaanxi Province, China. The grapes and juice were botrytized artificially by Botrytis spp. with high level of glycosidase activity. The winemaking process normally used for making sweet wine was used to make the artificial noble-rot wines. Normal sweet white wine and wine made from air-dried grapes were used as controls. The aromas of wine samples taken in April of the following year were subjected to chemical and sensory analyses. Botrytis-infected wines contained few higher alcohols but contained high esters and fatty acids, especially acetate esters, which were more likely due to high volatile acids induced by fungal infection. More varietal aroma-active compounds, especially terpenols and norisoprenoids, were detected in wines made from botrytized grapes and air-dried grapes than those in normal sweet white wine and botrytized juice made wine. The treatment of over-ripe grapes promoted hydrolysis of aroma precursors, meanwhile, the metabolic activity of B. cinerea also promoted the hydrolysis. Moreover, hydroxy benzoate esters were typical compounds in botrytis-infected wines and γ-decalactone, phenyl acetic acid and 2-nonanone were unique in wine made from botrytized grapes. The wine made from botrytized grapes had the most complex aroma profile, with sweet fruity, caramel, mango and toast flavors; wine made from botrytized juice had fewer aromas. Therefore, grapes botrytized artificially with B. cinerea could be used to make noble-rot wines with high aroma quality.
