The "frost" on the surface of Xiaoqing orange is not microorganism, but the crystallization of citrus volatile oil. Its main component is limonene, which is a monoterpene compound, colorless oily liquid with lemon-like fragrance. Limonene is a natural ingredient in many fruits (mainly citrus), vegetables and spices. Citrus fruits (especially peels) have a high content. Limonene has good antitussive, expectorant and bacteriostatic effects. Compound limonene is clinically used to promote gallbladder function, dissolve stones, promote the secretion of digestive juice and eliminate intestinal gas accumulation.

What factors are related to the formation of "white frost"?

First, limonene is volatile. If stored in a closed environment for a long time, these substances will slowly precipitate on the surface of orange peel and oxidize into white material, forming "white frost".

Secondly, the formation of hoarfrost is closely related to the origin and processing technology. In the producing areas, usually only the green husk in the core producing areas of Xinhui has the phenomenon of "white frost". The more citrus fruits there are in the core producing areas, the more oil bags there are on the citrus peel, and the more frost there will be. When processing, to "defrost", we must ensure the activity and integrity of the oil package. Only after repeated sun exposure and long-term low-temperature baking can frost precipitate on the surface of small green oranges.

03. How to distinguish "frost" from "mildew"?

Frost is basically a round white spot, while mold is a spreading cotton wool. Frost is usually white, while mold is usually brownish yellow or dark green.

Frost smells fruity, while mildew is an unpleasant musty smell.

Frost is dry and granular. If it is moldy, the mold will be slippery, lack of texture and fall off.

Therefore, "white frost" small green oranges can be drunk. Please feel free to drink and pay attention to the correct storage.