| Abstract: | The presence of sulfites in alcoholic beverages, particularly in wines, can cause allergic responses with symptoms ranging from mild gastrointestinal problems to life threatening anaphylactic shock in a substantial portion of the population. We have developed a simple and inexpensive biocatalytic method that employs wheatgrass (Triticum aestivum) chloroplasts for the efficient oxidation of sulfites in wines to innocuous sulfates. A sufficiently high rate of sulfite oxidation was obtained in the presence of ethanol at concentrations commonly found in most wines. Crude chloroplast preparations at a concentration as low as 5 mg/mL were capable of reducing sulfite in commercial white wines from 150 ppm to under 7.5 ppm within 3 hours. A 93% removal of sulfite in commercial red wines was observed with 1 mg/mL chloroplasts within 45 min. Optimal sulfite removal efficiency was observed at pH 8.5 and was promoted by illumination, indicating the participation of light-induced photosynthetic electron transport processes in sulfite oxidation. Overall, this work indicates that biocatalytic oxidation using wheatgrass chloroplasts can be employed to remove sulfites from beverages prior to consumption. |
