| Acetaldehyde, a naturally occurring oxidation product of ethanol, is a probable human carcinogen found in wine. In this experiment, it was monitored periodically by gas chromatograph equipped with nitrogen-phosphorus detector (GC-NPD). Due to the high volatility and water solubility of acetaldehyde, it was derivatized to 2-methylthiazolidine with cysteamine hydrochloride for GC analysis. Three types of wine were analyzed: organic white wine, regular white wine, and sherry. The white wine samples were stored at 6°C, 25°C, and 40°C without light exposure for 60 days, while the sherry wine samples were stored under the same condition for 40 days. As a result, the majority of the wine samples show a rise-peak-fall trend during the course of storage at various temperatures and headspace conditions. Highest acetaldehyde level was detected for organic white wine on Day 45, regular white wine on Day 30, and sherry wine on Day 20, indicating that the rate of acetaldehyde formation depends on the wine type. As predicted, temperature is a key factor in the formation of acetaldehyde. The amount of acetaldehyde formed is positively related to the storage temperature for organic white wine, but is negatively related to regular white wine and sherry. Another interesting finding is that the acetaldehyde levels in both types of regular wine are equal or greater than that in organic white wine, indicating the added sulfites could not completely eliminate acetaldehyde. These results have significance in food forensics by providing quantitative data of acetaldehyde exposure in wine. It is also useful for wine industry and customers to strictly control the storage conditions to avoid undesired oxidation which affects the quality and taste of wine. |
