Optimal Conditions for Effective Use of Acid Urease in Wine

摘要

Ethy Carbamate (EC), commonly called urethane, is a well-known carcinogen in experimental animals (Mirvish, 1968; Inai et al., 1991). EC has been identified in various fermented foods and beverages (Walker et al., 1974; Canas et al., 1989; Dennis et al., 1989; Fauhl et al., 1993). In 1976, Ough suggested that EC occurred naturally during fermentation (1976a, b). Published reports indicate that the major pathway of EC formation in wine is the reaction of ethanol with urea (Ough et al., 1988a; Mon-teiro et al., 1989), which has been detected at various concentrations in wine (Ough et al., 1990; Fujinawa et al., 1990). The urea in wine is produced by yeast metabolism of arginine from grape juice (Ough et al., 1988a). Our research group has reported that urea content in wine should be kept below 2 mg/L in order to control EC formation during aging and storage. This would also keep the concentration within target levels of wine industries in the US: 15 μ g/L in table wines and 60 μ g/L in dessert wines (weighed average basis, Kodama et al., 1994).