Learn the science behind why mint paste turns black so quickly. Discover how oxidation is the culprit and tips to slow down the process.
1 Answer
Mint paste blackens due to oxidation of phenolic compounds and enzymatic browning, especially when exposed to air and light over extended periods. Adding an acid like lemon juice can help prevent this.
Detailed Explanation:
Mint leaves contain phenolic compounds, which are naturally present in many plants. When mint paste is exposed to oxygen in the air, these compounds undergo oxidation. This process leads to the formation of dark-colored pigments, causing the paste to darken. Additionally, mint contains enzymes, such as polyphenol oxidase (PPO), that catalyze browning reactions. These enzymes react with phenolic compounds in the presence of oxygen, accelerating the browning process. Light can also contribute to the degradation of chlorophyll and other pigments in the mint, further contributing to the darkening effect. The longer the paste is stored, especially without proper preservation techniques, the more pronounced the blackening becomes.
Pro Tip:
To prevent mint paste from blackening, add a small amount of lemon juice or another acidic ingredient like vinegar during preparation. The acid inhibits the enzymatic browning process and acts as an antioxidant, slowing down oxidation. Store the paste in an airtight container in the refrigerator to minimize exposure to air and light.