Why do apples turn brown when cut?

What happens to a cut apple that has been left for a long time? It seems to have changed its "face" and turned into an unsightly brown color, making it unappetizing

Some people think that the ferrous ions in apples are oxidized to ferric ions by O2 in the air, so the apples turn yellow after peeling, but this is not the case

The browning of the apple cut surface is due to the oxidation of various phenolic compounds in the apple cells to form quinone compounds, which are slightly soluble in water, making the apple cut surface brownish yellow

How to keep cut apples from discoloring? Several methods are available:

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The tannin organic substances in the apple flesh will also react chemically with the iron of the blade to form a black iron tannate covering the surface of the apple flesh, making the cut surface of the apple discolored

This article is scientifically checked by Han Sujuan, a senior teacher of the No.