When persimmon is not ripe, persimmon meat contains a lot of tannic acid, which has strong convergence. It can stimulate the tactile nerve endings in the mouth to get excited, but it has a "astringent" feeling and a bad taste. Moreover, the content of tannin (tannic acid) in persimmon varies greatly, generally between 0.4% and 4%.
The tannin content of mature sweet persimmon can be as low as 0. 1%, while the tannin content of immature persimmon can be as high as 4%. After eating persimmon with high tannic acid content, tannic acid will combine with protein in food under the action of gastric acid to form a precipitate, which is easy to form stones.
Extended data
Persimmons are astringent because they contain more soluble tannins and have astringent effects on oral mucosa. The purpose of artificial astringency removal with ripening agent is to convert soluble tannins into insoluble tannins, so that persimmons have no astringency when eaten in the mouth.
At present, ethephon used in the market is a common ripening agent, and the ethylene released by it can make persimmon ripen quickly. Vendors will dilute ethephon with water and apply it to the bottom of persimmon with a small brush. Within three days, the persimmon will change from hard to soft, and the color will become more and more red, which looks no different from the mature persimmon.
A small amount of ethephon is generally not harmful to human body, but if green persimmon is ripened and marketed prematurely, it needs a large amount of ethephon, so that there will be more residues in the fruit, and long-term consumption will interfere with the endocrine system of human body and endanger health. When consumers eat persimmons, if they find that the color is beautiful, but the taste is very light, it means that ripening agents are used.
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