Traditional fermentation technology application of the narrative is correctly

The application of traditional fermentation technology is correctly described as C. The temperature should be controlled at 18~30 ℃ for fruit wine fermentation and 30~35 ℃ for fruit vinegar fermentation.

Traditional fermentation techniques are applied to make kimchi, fruit wine and red wine. In the process of making wine, bubbles will be produced in the fermentation liquid, which is due to the yeast fermentation to produce CO2; if the wine is made from purple grapes, with the prolongation of the fermentation time. More and more anthocyanins will enter the fermentation liquid from the fruit skin, thus the color of the fermentation liquid will gradually deepen into a deep red.

Fruit vinegar fermentation process generally does not appear bubbles, when the fermentation is completed, a layer of bacterial film, which is the acetic acid bacterial film, will appear on the liquid surface of fermentation liquid. The development of traditional fermentation technology, fruit wine in addition to yeast, lactic acid bacteria, acetic acid bacteria and other microorganisms.

Principle of fruit vinegar production:

The bacterial strain is Acetobacter, which belongs to prokaryotic organisms, and the type of metabolism is heterotrophic aerobic. Only when there is enough oxygen can it carry out vigorous life activities. The film observed on the surface of the sour wine is the acetic acid bacteria in the liquid surface of a large number of breeding formation.

Note: Acetobacter is a prokaryotic organism, although there is no mitochondria, but there are many enzymes related to aerobic respiration on the inner side of their cell membranes, so they can carry out aerobic respiration, and cyanobacteria and nitrobacteria and so on, although they are also prokaryotic organisms, but they can carry out aerobic respiration as well.

When oxygen and sugar sources are sufficient, acetic acid bacteria will decompose the sugar in grape juice into acetic acid, when the lack of sugar sources, acetic acid bacteria will be ethanol into acetaldehyde, and then acetaldehyde into acetic acid, the reaction simple formula for C2H5OH + O2 → CH3COOH + H2O. acetic acid bacteria are best suited to the growth of the temperature of 30 ~ 35 ℃.