Is the white bloom on fruit pesticide residue or a normal phenomenon?
Recently, a netizen left a message asking why the plums they bought all had a layer of "white bloom" on the surface, and it was very hard to wash off. Is this layer of white bloom really pesticide residue?
In fact, it is not only plums that have this white bloom; among fruits, the surfaces of grapes, plums, sugarcane, blueberries and even winter melon also have a similar layer of white bloom. In fact, this white bloom is a sugar alcohol substance secreted by the fruit or vegetable itself, also called bloom, and it is not pesticide residue!
The scientific name of this "bloom" is "fruit bloom", a natural sugar alcohol substance secreted by the fruit or vegetable itself, and it is completely harmless to the human body. These compounds are insoluble in water but soluble in organic solvents such as chloroform, so whether you soak them in water, wash them or rub them, you cannot completely remove this layer of white bloom from the peel. However, it does not matter even if you cannot wash off this white bloom. Because it does not harm our health, and may even help protect the liver and fight viruses, you can eat it without worry. The legend that flour can wash off the white bloom is not actually removing the white bloom, but merely changing the structure of the white bloom or filling in the gaps between the white bloom crystals.
This layer of fruit bloom has a protective effect on fruit. For example, this layer of fruit bloom on the surface of grapes can reduce water evaporation, thereby preventing the fruit from quickly losing water and shriveling after picking, and it plays a positive role in adapting to arid environments. The water-insoluble property of fruit bloom can prevent the formation of a moist environment on the grape surface, thereby reducing infection by pathogenic bacteria. The white bloom on the grape surface also contains yeast, so when making homemade wine, no additional yeast needs to be added during fermentation. It needs to be explained that grapes are a fruit not prone to insects, and bagging is mostly used in cultivation now, so the chance of using high-concentration pesticides is very small. Therefore, if it is confirmed to be the grape's own white bloom, there is no need to wash it off.
To some extent, having white bloom is a sign that grapes are fresh, but it cannot rule out that some vendors spray low-concentration fungicide pesticides. The specific way to distinguish them is: normal "white bloom" is distributed naturally and evenly, and does not cover the grape skin's own color, making the grapes look more beautiful. If it is a chemical "white bloom", however, its appearance is unevenly distributed, and there will also be dark blue traces in it.
Therefore, when you see fruit with "white bloom" in the future, friends, you can buy it with confidence, because that is the freshest fruit!