Is pickles healthy?

Vegetables are a good source of natural vitamin C, but vitamin C has poor thermal stability and is easily oxidized and inactivated. Exposing vegetables to the air for a long time after cutting, or frying for a little longer, will cause a lot of loss of vitamin C. Pickled vegetables are also exposed to the air for a long time during the pickling process, so there is basically little vitamin C left in pickled vegetables. For example, Chinese cabbage, white radish and sherry red (commonly used raw materials for mustard tuber) are all vegetables rich in vitamin C. However, after pickled into pickles, only tough substances such as inorganic salts such as cellulose and calcium can survive, and their nutritional value is greatly reduced. Moreover, even deteriorated vegetables can remedy defects in shape and color after processing, so it is not easy to judge whether their raw materials are fresh or not.

From this perspective, eating pickles is actually not about nutrition, but mainly about taste and taste. However, canned sufu is a special case. Sufu is mainly the product of soybean fermented protein in the long-term pickling process, which is rich in various amino acids and peptides and has unique nutritional value.

As many people know, vegetables will produce nitrite in the pickling process, which is harmful to human body and may also be converted into carcinogenic nitrosamines. In fact, fresh vegetables also contain nitrate and nitrite, but because vitamin C exists widely in fresh vegetables, nitrite can be reduced to nitric oxide under suitable conditions to reduce the amount of nitrite. However, vitamin C in pickled pickles is almost completely inactive, so nitrite in pickles may accumulate in human body, and may form nitrosamines with secondary amine, a decomposition product of protein.

With the progress of curing, nitrate in vegetable raw materials can gradually become nitrite under the action of bacteria. Therefore, in saline-alkali areas and areas where nitrogen fertilizer is widely used, vegetables are not suitable as raw materials for kimchi because of their high nitrate content. In addition, the research shows that the nitrite content in pickles increases with the extension of pickling time, and it is also related to pickling water, pH value of pickling solution and environmental sanitation. The study also found that the consumption of kimchi was positively correlated with the incidence of gastric cancer.

However, there is no need to be too afraid of nitrite. Nitrite itself has antiseptic effect and can discolor meat. It is a common colorant and preservative in meat processing (for example, you need it when you buy meat-colored powder in the supermarket). A small amount of nitrite is harmless to human body, and excessive nitrite can cause poisoning symptoms such as hypoxia and even death. In order to reduce the harm of nitrite, fresh vegetables or fruits with high vitamin C content can be supplemented while eating pickles, which has degradation effect.