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

2. Pour an appropriate amount of water into the tank, put an appropriate amount of salt into the water, and let the salt dissolve in the water.

3. Put the washed cabbage into the jar. The height of the cabbage should be higher than the mouth of the jar, and then press the big stone on the cabbage.

4. After 10-15 days, the pickled cabbage will turn golden brown and can be eaten.

Principles of pickling

During the pickling process, vegetables undergo complex changes in appearance and composition. These changes can be divided into two aspects: osmosis and fermentation (see food pickling and preservation). Osmosis uses the higher osmotic pressure of table salt to prevent the growth and development of microorganisms.

The higher the salt concentration when pickling vegetables, the better the preservative effect. However, high-concentration salt solutions will cause strong osmosis, and the vegetables will shrink due to the sudden loss of water in the cells. To avoid shrinkage, add salt in layers. The concentration of brine used will vary depending on the type of vegetable.

For vegetables with delicate tissues and thin cell fluid, less salt should be added; otherwise, more salt should be added. For example, the amount of salt used in cabbage is 4 to 5%, that of potherb mustard is 8%, that of mustard is 12%, and that of pepper is 15 to 20%.

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

The fermentation of sugar in vegetables mainly includes lactic acid fermentation (lactic acid bacteria decompose sugar to produce lactic acid; or, in addition to producing lactic acid, it can also produce acetic acid, ethanol and carbon dioxide), alcoholic fermentation (produced by alcohol mother) Fermentation of sugar to produce ethanol), acetic fermentation (fermentation of sugar to produce ethanol, and then oxidation to acetic acid) and butyric acid fermentation (butyric acid bacteria decompose sugar to produce butyric acid), etc.

Because the sugar content of vegetables is acted upon by different microorganisms, the products produced by fermentation are also different. During the alcoholic fermentation and acetic acid fermentation, the trace amounts of ethanol produced combine with acetic acid to produce esters, and the aroma can enhance the flavor of pickles.

Butyric acid produced by butyric acid fermentation is not only useless for pickling vegetables, but also makes pickles taste bad, so it should be prevented. The fermentation of lactic acid bacteria does not require air, and most film-producing yeasts and molds are aerobic bacteria. Therefore, vegetables should be pressed or sealed when pickling, and they can also be flooded with salt water to isolate the air.

Potential hazards

During the pickling process, nitrite can inhibit the growth of Clostridium botulinum and other types of spoilage bacteria, and has good color rendering and antioxidant effects. , and can improve the flavor of pickled foods. However, nitrite can react with amines, the protein decomposition products in pickled products, to form nitrosamines, which are strong carcinogens. The presence of nitrite in pickled foods is a major potential hazard.

Traditional vegetables take a long time to pickle, and they cannot be eaten after just a few days. Generally speaking, the nitrite content will continue to increase at the beginning of pickling vegetables, reach a peak and then decrease. This peak is called nitrite peak. Some vegetables have one peak, and some have three peaks.

When pickling vegetables, you should choose vegetables with less nitrogen fertilizer. Try to wash the vegetables as clean as possible, and use clean water and tanks to pickle them so that less air enters the vegetable pickling tank.

In order to reduce the nitrite content in pickled vegetables, you can also add some vitamin C when pickling the vegetables. Add 4 capsules of vitamin C to 1 kilogram of cabbage. The main function of adding vitamin C is to block The formation of nitrite can also prevent sauerkraut from growing mold and reduce rancidity and odor. There should also be enough salt to marinate thoroughly. If insufficient salt is used, the bacteria cannot be completely inhibited, which will cause the nitrate in the dish to be reduced to harmful nitrite. ?

Reference material Baidu Encyclopedia - Pickled vegetables