Malolactic fermentation can have a significant impact on biogenic amine concentrations in wine. This process, which occurs after alcoholic fermentation, involves the conversion of harsh malic acid into softer lactic acid by lactic acid bacteria. While malolactic fermentation is crucial for improving the taste and stability of wine, it can also influence the levels of biogenic amines present in the final product.
Biogenic Amines in Wine
Biogenic amines are organic compounds that are naturally present in various foods and beverages, including wine. These compounds are formed through the decarboxylation of amino acids by microbial enzymes. Biogenic amines can have both positive and negative effects on human health, with high levels being potentially harmful. The most common biogenic amines found in wine include histamine, tyramine, putrescine, and cadaverine.
Impact of Malolactic Fermentation
During malolactic fermentation, lactic acid bacteria such as Oenococcus oeni metabolize malic acid, producing lactic acid and carbon dioxide. This process can have several effects on biogenic amine concentrations in wine:
- Reduction in Biogenic Amines: Malolactic fermentation can lead to a decrease in biogenic amine levels in wine. This is because lactic acid bacteria consume amino acids that are precursors to biogenic amines, thereby reducing their concentration in the final product.
- Formation of Biogenic Amines: On the other hand, malolactic fermentation can also contribute to the formation of certain biogenic amines. Some lactic acid bacteria have decarboxylase enzymes that can convert amino acids into biogenic amines, particularly histamine and tyramine.
- Interaction with Yeast: The interaction between lactic acid bacteria and yeast during fermentation can also influence biogenic amine concentrations. Yeast can produce compounds that affect the growth and activity of lactic acid bacteria, potentially impacting the formation or degradation of biogenic amines.
Factors Affecting Biogenic Amine Levels
Several factors can influence the levels of biogenic amines in wine, including:
- Grape Variety: Different grape varieties contain varying amounts of amino acids, which can affect the potential for biogenic amine formation during fermentation.
- Fermentation Conditions: Factors such as temperature, pH, and oxygen exposure during fermentation can impact the growth and activity of lactic acid bacteria and yeast, thereby influencing biogenic amine levels.
- Microbial Strains: The specific strains of lactic acid bacteria and yeast present during fermentation can determine the extent of biogenic amine production or degradation in wine.
- Winemaking Practices: Techniques such as malolactic fermentation, aging on lees, and the use of additives or fining agents can all play a role in shaping biogenic amine concentrations in wine.
Regulatory Considerations
Due to the potential health risks associated with high levels of biogenic amines, regulatory authorities have established limits for these compounds in wine. In the European Union, maximum limits have been set for histamine and tyramine in wine, with the aim of protecting consumer health and safety.
Monitoring and Mitigation Strategies
Winemakers can employ various strategies to monitor and mitigate biogenic amine levels in wine, including:
- Analysis: Regular testing for biogenic amines using analytical techniques such as high-performance liquid chromatography (HPLC) can help winemakers assess the levels of these compounds in their products.
- Controlled Fermentation: Implementing controlled fermentation conditions, such as temperature and pH control, can help minimize the formation of biogenic amines during winemaking.
- Selection of Microbial Strains: Choosing lactic acid bacteria and yeast strains with low decarboxylase activity can reduce the risk of biogenic amine production in wine.
- Hygiene Practices: Maintaining strict hygiene practices in the winery can help prevent contamination by biogenic amine-producing microorganisms.