What is the fermentation principle of baking powder?
Yeasts are the earliest microorganisms used in the history of human civilization. Yeasts contain various enzymes, such as amylase. During fermentation, amylase first turns the starch in the flour into sugar, which then turns the sugar into carbon dioxide. The carbon dioxide is heated and expanded when steaming the steamed bread, which leaves many small holes in the steamed bread, and also produces a small amount of alcohol and ester volatile acid, so it is very soft and delicious to eat.
When I was a child, I ate the steamed buns that my mother had just steamed. I can’t help but ask: “Mom, why is the steamed bun so soft?” Mom always says, “This is the effect of baking powder.” Let’s learn about baking powder today.
In fact, baking powder contains yeast, and yeast is the earliest microorganism used in the history of human civilization. Yeasts contain various enzymes, such as amylase. During fermentation, amylase first turns the starch in the flour into sugar, which then turns the sugar into carbon dioxide. The carbon dioxide is heated and expanded when steaming the steamed bread, which leaves many small holes in the steamed bread, and also produces a small amount of alcohol and ester volatile acid, so it is very soft and delicious to eat.
However, fermenting with fresh yeast requires extensive experience. Because this fermentation method takes a long time, if the control is not good and the fermentation is overdone, the noodles will be sour or not soft enough. Later, people replaced the role of yeast with a chemical fluffing agent, that is, baking powder. Baking powder is different from fresh yeast. It does not contain yeast. After being heated, it directly produces carbon dioxide gas, which makes bread, steamed bread, etc. appear many small holes and become soft. There are four kinds of baking powder that are used more at present.
1. Baking soda (sodium bicarbonate)
Under the action of acidic substances contained in food, baking soda can be decomposed into sodium ions, water and carbon dioxide gas, which can play a fluffy role. However, the reaction of baking soda to release gas requires the presence of acidic substances, which is completed in a short period of time, and the initiation of the reaction is difficult to control. If the amount is too large, bitterness or astringency will be produced. For these reasons, baking soda is rarely used alone as a leavening agent, but is generally one of the components of a complex leavening agent.
2. Smelly powder (ammonium bicarbonate)
Odor powder is generally used when a large amount of gas needs to be generated quickly. The smelly powder is not resistant to heat. As long as the temperature rises to 60-70 °C, it will decompose and release a large amount of carbon dioxide and ammonia. Due to the rapid release, very little ammonia remains in the finished product, so there is no smell of ammonia. However, because the smelly powder is easy to decompose and release ammonia gas and lose its effect, it is difficult to store and is generally less used in the family. Stinky flour is used when baking peach crisps or certain cookies.
3. Alum (Potassium Aluminum Sulfate or Potassium Aluminum Sulfate)
Commonly used alum is actually an acidic mixture that emits gas when it interacts with food inherent or added ingredients such as baking soda, and plays a fluffy role. Generally, it is also a component of acid as a complex fluffing agent. The characteristic is that it can react quickly at high temperature. A common example is to fry fried dough sticks.
4. Baking powder
This is a composite fluffing agent, which is generally a mixture of solid alkali and acid powder. They do not react under dry conditions. Once they meet water, they will dissolve and react, releasing gas. Baking soda is commonly used for solid alkali powder, and solid acid powder includes tartrate (tartar) and phosphate (such as calcium phosphate and sodium pyrophosphate), which have a fast reaction speed. In addition, there is also the use of alum as a solid acid, the reaction rate is much slower, but very fast at high temperature. Because baking powder is easy to store and control, it has become the most commonly used fluffing agent at present, and baking powder is used in most pastries. Some self-raising flours sold in the market have also been mixed with baking powder, which needs to be quickly shaped and placed in the oven after adding water.
5. The hazards of chemical fluffing agents:
Since the reaction products of baking soda and stinky powder (carbon dioxide, ammonia) are also products of human metabolism, as long as they are not used in excess, they will not cause obvious health problems, but will destroy some nutrients in food such as vitamins. Alum and baking powder both contain aluminum. Many international reports have pointed out that aluminum is closely related to senile dementia, and it also reduces memory and inhibits immune function, hinders nerve conduction, and the excretion of aluminum from the human body is very slow. Regarding the use of baking powder, especially aluminum-containing Alum and baking powder, we should mainly pay attention to avoid excessive intake of aluminum, and try to eat less food containing aluminum. The aluminum contained in food will cause harm to human body if it exceeds the national standard.
Baking powder is a chemical leavening agent.
Yeast is a biological fluffing agent.
Yeast is a single-celled facultative anaerobic eukaryotic microorganism. After being added to the dough, it can generate carbon dioxide gas through its own metabolism to achieve the purpose of fluffing. This process is usually called fermentation. In the past, old noodles were often used for fermentation, mainly relying on wild yeast and some miscellaneous bacteria. The dough often contained organic acids and made it sour. It was necessary to add baking soda to neutralize the sour taste. Metabolites from miscellaneous bacteria and added baking soda can introduce harmful components or destroy nutrients. The active yeast commonly used in modern times has high purity and rarely produces acidic substances. At the same time, yeast itself is composed of protein and carbohydrates, and is rich in B vitamins and other trace elements such as calcium and iron, and has a high nutritional value. value. Yeast, as a fluffing agent for pasta, needs enough time and temperature to generate carbon dioxide.
Obviously, yeast is a kind of beneficial biological fluffing agent, which has no negative effect on the human body, and can provide nutrients and vitamins that are necessary and lacking in human beings. It is the most ideal fermentation method. It is essentially different from chemical baking powder. All in all, yeast is not chemical baking powder!