Changes in temperature and substance during fermentation
Abstract：A series of complex biochemical reactions in fermentation cellars must be reflected in material changes, which is a convenient and simple way to study fermentation dynamics in cellars. We investigated the fermentation temperature and substance changes in the cellars of wine and other Luzhou-flavor koji, and found that there are common rules. After the cellars are sealed, the yeast uses the germanized liquor in the fermentation tank, the enzyme hydrolysis, the nitrogen acid and the remaining oxygen in the cellars to multiply.
A series of complex biochemical reactions in fermentation cellars must be reflected in material changes, which is a convenient and simple way to study fermentation dynamics in cellars. We investigated the fermentation temperature and substance changes in the cellars of wine and other Luzhou-flavor koji, and found that there are common rules.
After the cellars were sealed, the yeast used the germanized liquor in the fermentation tank, the enzyme hydrolysis, the nitrogenous acid and the remaining oxygen in the cellars to multiply, and some aerophilic bacteria also grew in large numbers, so the temperature in the cellars rose rapidly. Because the fermentation of Qu wine is governed by natural conditions, the product temperature rise varies with the season, and the product temperature rises to a higher level in about 5 days, which is about 7-14℃ higher than when it is stored in the cellar. As the temperature rises, saccharification and fermentation accelerate, and with the increase of oxygen consumption Co:, yeast changes from respiration to fermentation.
At this time, the growth of yeast is inhibited, the number of cells is greatly reduced, the fermentation rate is slowed down, and the product temperature is gradually decreased, and the product is slowly decreased after 20 days and 30 days after the cellar is sealed until the end of the fermentation. This created a favorable environmental condition for the requirement of slow digestion and drunkenness of Qujiu production.
With the metabolic activities of acid-producing bacteria such as acetobacter, butyric bacteria, lactic acid bacteria, caproic acid bacteria and other microorganisms in the cellar, organic acids gradually accumulate, reflecting the slow rise of acidity during the fermentation process, while the pH changes little. This shows that the fermentation grains have a certain buffer capacity, which is conducive to the fermentation of yeast and the catalytic reaction of enzymes. The production and accumulation of organic acids in the fermentation grains are directly related to the formation of various flavor components.
After the cellars were sealed, the yeast used the germanized liquor in the fermentation tank, the enzyme hydrolysis, the nitrogenous acid and the remaining oxygen in the cellars to multiply, and some aerophilic bacteria also grew in large numbers, so the temperature in the cellars rose rapidly. Because the fermentation of Qu wine is governed by natural conditions, the product temperature rise varies with the season, and the product temperature rises to a higher level in about 5 days, which is about 7-14℃ higher than when it is stored in the cellar. As the temperature rises, saccharification and fermentation accelerate, and with the increase of oxygen consumption Co:, yeast changes from respiration to fermentation.
At this time, the growth of yeast is inhibited, the number of cells is greatly reduced, the fermentation rate is slowed down, and the product temperature is gradually decreased, and the product is slowly decreased after 20 days and 30 days after the cellar is sealed until the end of the fermentation. This created a favorable environmental condition for the requirement of slow digestion and drunkenness of Qujiu production.
With the metabolic activities of acid-producing bacteria such as acetobacter, butyric bacteria, lactic acid bacteria, caproic acid bacteria and other microorganisms in the cellar, organic acids gradually accumulate, reflecting the slow rise of acidity during the fermentation process, while the pH changes little. This shows that the fermentation grains have a certain buffer capacity, which is conducive to the fermentation of yeast and the catalytic reaction of enzymes. The production and accumulation of organic acids in the fermentation grains are directly related to the formation of various flavor components.
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