How to pickle vegetables?

1. Cut off the roots of the cabbage, remove the rotten parts of the leaves, and clean the cabbage with clear water.

2. Pour the right amount of water into the jar, and put the right amount of salt into the water to make the salt dissolve in the water.

3. Put the washed cabbage in the jar, the height of the cabbage is higher than the jar mouth, and then press the big stone on the cabbage.

4. After 10- 15 days, the cabbage can be eaten after being salted into golden yellow.

Pickling principle

During the curing process, the appearance and distribution of vegetables have undergone complex changes. These changes can be divided into two aspects: infiltration and fermentation (see food preservation). Osmosis is to use the high osmotic pressure of salt to prevent the growth and development of microorganisms.

The higher the salt concentration, the better the anticorrosion effect. However, high concentration of salt solution will cause strong osmosis, and vegetables will shrink because of the sudden loss of water in cells. In order to avoid shrinkage, salt can be added in layers. The concentration of salt water used varies with the type of vegetables.

Vegetables with delicate tissues and thin cell fluid should be added with less salt; On the contrary, you can add more. For example, the salt content of Chinese cabbage is 4-5%, sherry red is 8%, mustard is 12%, and pepper is 15-20%.

Fermentation is the use of microorganisms to decompose complex organic compounds such as carbohydrates and protein in vegetables into simple compounds to obtain nutrients necessary for energy and growth. They have a continuous process of decomposing organic matter in vegetables. Generally, sugar is decomposed first, then pectin and hemicellulose, and then protein is decomposed.

The fermentation of sugar in vegetables mainly includes lactic acid fermentation (sugar is decomposed by lactic acid bacteria to produce lactic acid; Or, in addition to lactic acid, it can also produce acetic acid, ethanol and carbon dioxide), alcohol fermentation (alcohol mother ferments sugar to produce ethanol), acetic acid fermentation (sugar fermentation produces ethanol and then oxidizes it into acetic acid) and butyric acid fermentation (butyric acid is produced by decomposing sugar by butyric acid bacteria).

Because the sugar of vegetables is affected by different microorganisms, the products produced by fermentation are also different. In the process of alcohol fermentation and acetic acid fermentation, a small amount of alcohol and acetic acid combine to form esters, which can enhance the flavor of kimchi.

Butyric acid produced by butyric acid fermentation is not only beneficial to the pickling process of vegetables, but also makes kimchi unpalatable and should be prevented. Lactic acid bacteria do not need air for fermentation, and membrane-producing yeast and mold are mostly good aerobic bacteria, so vegetables should be pressurized or sealed when pickled, or they can be submerged with salt water to isolate the air.

potential hazard

Nitrite can inhibit the growth of spoilage bacteria such as Clostridium botulinum, and has good coloring and antioxidant effects, and can improve the flavor of pickled food. However, nitrite can react with amine, the decomposition product of protein in pickled products, to generate nitrosamines, which are a strong carcinogen, and the existence of nitrite in pickled products is the main potential hazard.

Traditional vegetables take a long time to marinate and cannot be taken out for several days. Generally speaking, the content of nitrite will increase at the beginning of vegetable curing, and then it will decrease after reaching a peak. This peak is called nitrite peak. Some vegetables have one peak, while others have three peaks.

When pickling vegetables, choose vegetables with less nitrogen fertilizer, wash them as clean as possible, and pickle them with clear water and tanks, so that there is less air in the vegetable pickling tanks.

In order to reduce the nitrite content in pickled vegetables, vitamin C can also be added when vegetables are pickled, and 4 tablets of vitamin C can be added to 1 kg of Chinese cabbage. The main function of adding vitamin C is to block the generation of nitrite, and at the same time, it can also prevent sauerkraut from moldy and reduce rancidity and odor. Put enough salt and marinate thoroughly. Without enough salt, bacteria can not be completely inhibited, which will reduce nitrate in vegetables to harmful nitrite. ?

Refer to Baidu Encyclopedia-Vegetable Pickling