The content of this one is boring, but for the yeast fermentation reaction has a very important understanding, we first come to understand the difference between aerobic fermentation and anaerobic fermentation. Yeast can be fermented in an anaerobic or aerobic state (or it is called anaerobic for fermentation, aerobic respiration), but the process is different from the product.
Yeasts are essentially facultative anaerobic organisms, the so-called facultative anaerobic organisms, meaning that in an aerobic environment can survive, in the aerobic environment, the implementation of aerobic respiration, in an oxygen-free environment, the implementation of fermentation (Fermentation), fermentation is not yeast-specific, including lactic acid bacteria, acetic acid bacteria will be different fermentation chemical reaction.
In the absence of oxygen, the yeast is subjected to anaerobic fermentation in which glucose is converted to CO2 and ethanol and produces energy (ATP) by glycolysis.
C6H12O6 → 2C2H5OH + 2CO2 + 2ATP
In the aerobic conditions, yeast can quickly bud propagation, yeast glucose by aerobic breathing (glycolysis → tricarboxylic acid cycle) metabolism of CO2 and H2O.
C6H12O6 + 6O2 → 6CO2 + 6H2O + 30 (32) ATP
So generally generally recognized the advantages and disadvantages of aerobic fermentation and anaerobic fermentation are as follows:
Advantages of anaerobic fermentation:
Can produce alcohol (ethanol), and alcohol will be another organic acid into ester, and ester is an important source of bread flavor. So the bread with anaerobic fermentation when the bread flavor will be better.
Advantages of aerobic fermentation:
Can effectively produce gas, aerobic fermentation of a glucose can produce 6 CO2, than the anaerobic fermentation will only produce more than 2 CO2. So be able to produce a lot of gas, increase the bread volume. But because there is no alcohol in the fermentation process, so the flavor will be less than the loss of a lot of flavor, that is not necessarily good reason for the pores here.
See here, we are not to be aerobic fermentation, to overturned, so that dough contact with fresh air, you can promote the conduct of aerobic fermentation. If the dough as far as possible with the air, it will promote the conduct of anaerobic fermentation But things are not as simple as imagined.
Yeast as long as there is glucose, even in the case of oxygen, it is also taking this alcohol fermentation path, until the glucose run out!
Therefore, the aerobic fermentation of yeast and anaerobic fermentation is not just the difference between aerobic and anaerobic environment, in a glucose environment, the yeast must be the first anaerobic fermentation (alcohol fermentation). And until the yeast runs out of glucose, the use of other sugars or amino acids, it may be aerobic fermentation. While the general flour or yeast has enzymes that can decompose maltose or sucrose into glucose to provide yeast nutrients.
Seemingly simple yeast fermentation, in fact, there are very far behind the principle with the knowledge.
This article comes from the happy baking network
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