No, vitamins don't evaporate from juice. However, they do degrade over time.
Vitamin Degradation in Juice
The statement "juice loses its nutritional value over time" accurately reflects what happens. This loss isn't due to evaporation, but rather to oxidation and degradation caused by exposure to light and oxygen. Sensitive vitamins and other nutrients break down, reducing the overall nutritional benefit of the juice.
Think of it this way: Vitamins aren't volatile compounds that turn into a gas and disappear into the air. Instead, their chemical structure changes, rendering them less effective. Leaving juice uncovered accelerates this process.
Factors Affecting Vitamin Loss in Juice:
- Oxygen Exposure: Contact with air leads to oxidation, damaging vitamins.
- Light Exposure: UV light from the sun can degrade some vitamins.
- Time: The longer juice sits, the more degradation occurs.
- Temperature: Higher temperatures speed up the degradation process.
Practical Tips to Preserve Juice Nutrients:
- Store juice in airtight containers.
- Refrigerate juice immediately after juicing or purchasing.
- Consume juice as soon as possible after juicing or opening.
- Minimize exposure to light.
This information supports the provided reference's statement about juice losing nutritional value over time. The key is to understand that this loss is primarily due to chemical degradation, not evaporation.