Summer and autumn is a good time to eat grapes, but many people will find that when they buy grapes in fruit shops, there is a layer of white frost on the grape mountain, and it is very difficult to clean it, so what is the white frost on the surface of grapes? Is the white frost on the surface of grapes pesticide residues?
Can the white frost on the grape skin be eaten?
In fact, there is not only white frost on the surface of grapes, but also a layer of frost like substance on the surface of plum, sugarcane, blueberry and even winter melon. Don't worry, this white frost is not a harmful substance.
This layer of white frost is the sugar and alcohol substances secreted by fruits and vegetables themselves, also known as fruit powder. They belong to the natural substances of biosynthesis and are completely harmless to human body. It doesn't matter if you don't wash it thoroughly.
And, to some extent, with white frost is a sign of whether the grapes are fresh or not. But it can not be completely avoided that some merchants spray low concentration of fungicides.
How to distinguish the normal white frost: the normal white frost is distributed naturally and evenly, and does not cover the color of the grape skin itself, making the grape look more beautiful. If the frost effect is caused by the agent, its appearance distribution is uneven, and there will be traces of dark blue.
The effect of white frost on grape skin the white frost on grape skin is not only harmless to people, but also has a great effect.
1. Adapt it to the arid environment
This layer of fruit powder has a protective effect on fruit. For example, this layer of fruit powder on the surface of grape can reduce water evaporation, thus preventing rapid water loss and shrinkage after picking, and has a positive effect on adapting to the dry environment.
2. Reduce the infection of pathogenic bacteria
The water-insoluble property of this layer of fruit powder can avoid the formation of a humid environment on the surface of grapes, thus reducing the infection of pathogens.
3. No need to add yeast to make wine
This layer of white cream on the surface of grape also contains yeast, so the self-made wine can be fermented without additional yeast.