What are the applications of traditional fermentation technology?

The application of traditional fermentation technology includes making kimchi, fruit wine and red wine.

In the process of wine production, bubbles will be produced in the fermentation broth, which is because yeast fermentation produces CO2；; If purple grapes are used to make wine, with the extension of fermentation time.

More and more anthocyanins will enter the fermentation broth from the peel, so the color of the fermentation broth will gradually deepen and become deep red. Generally, there will be no bubbles during the fermentation of fruit vinegar. After the fermentation is completed, a bacterial membrane will appear on the liquid surface of the fermentation liquid, which is the acetic acid bacterial membrane.

Development of traditional fermentation technology

In addition to yeast, there are microorganisms such as lactic acid bacteria and acetic acid bacteria in fruit wine. Lactic acid bacteria can decompose sugar, glycerol, tartaric acid and so on. In fruit wine, thus making fruit wine deteriorate. The content of lactic acid bacteria can be controlled by adjusting fermentation temperature and pH of fruit wine. Sugar in fruit juice is also an important source of carbon and energy for Acetobacter.

Acetobacter can decompose sugar into acetic acid in the presence of oxygen; In the absence of sugar source, ethanol is the carbon source and energy source of Acetobacter, which converts ethanol into acetaldehyde, and then acetaldehyde into acetic acid. Because acetic acid bacteria can only carry out vigorous metabolic activities under aerobic conditions, the growth and reproduction of acetic acid bacteria can be inhibited by reducing the O2 content as much as possible during fruit wine brewing.

In addition, the content of acetic acid bacteria can be controlled by adjusting fermentation temperature and pH value of fruit wine. With the progress of acetic acid fermentation, the pH and fermentation temperature of fermentation broth are not conducive to the growth and reproduction of yeast, so the activity of yeast is very low.

Under our experimental conditions, when the bottle cap is opened, the acetic acid bacteria in the air will enter the fermentation broth and multiply in large quantities, while other bacteria cannot reproduce because they are not adapted to the environmental conditions. In industry, the late fermentation of vinegar needs artificial inoculation of acetic acid bacteria.