Aging mechanism of fermented dough such as bread, steamed buns, and baked cakes
Starting | Du Dechun
The main characters in the fermented dough, bread and steamed buns, are aged due to starch moisture escape and starch aging.
Trace the causes of aging, treat the disease and seek the root cause; in order to effectively solve it.
The bread that has been cooled remains fresh for an extended period of time.
But inside the bread, the water gradually begins to transfer from the center to the epidermis, the moisture is gradually decreased slowly, the rate of water loss varies according to the volume of the bread and environmental conditions, the small long bread is fast, the large round bread is slow; The climate is fast when it is dry, and slow when it is wet.
When the relative humidity of the environment is low, moisture is emitted into the atmosphere through the bread crust, and the bread becomes hard and crisp; When the relative humidity is high, although the water transfer is carried out as usual, the water loss is much slower, and some of the water stays in the bread crust, causing the crusb to wrinkle and soften.
After 18 to 24 hours of bread fermented with yeast and 48 hours of bread fermented with flour fat, regardless of the relative humidity, the bread placed at room temperature will have another change: the skin is no longer crispy, and it is soft or hard, the bread is lost in elasticity and softness, it is easy to drop the slag, the bread loses its unique aroma, and the taste deteriorates: the bread has aged.
The mechanism of bread aging is still not very clear, and scientific research has only put forward a few hypotheses. To be sure:
Loss of moisture is not the only cause of bread aging.
Some researchers attribute the cause of aging to chemical changes (changes in the configuration of molecules), that is, the crystallization of starch. However, the crystallization of starch is irreversible, and the aging bread can be restored to freshness in a short period of time after returning to the oven under conditions that are not excessively dry.
In addition, the author believes that changes in physical properties have occurred during the aging process of bread. Physical changes are reversible, which partly explains why aging bread can be reheated to freshness.
Bread fermented with flour fertilizer ages much more slowly than those fermented with yeast. In the former case, the gluten in the ball in front of the furnace can hardly be extracted, while in the latter case, the gluten can be extracted almost completely.
Therefore, some people think that the aging of bread also has a lot to do with gluten.
Other production factors can also affect the speed of bread aging, such as the use of overheated water when mixing, the use of too much yeast during fermentation, or the use of more inoculation dough, and the addition of a certain number of yeasts, which will accelerate the aging of bread.
Environmental conditions also have an impact on aging, in practice, often use the method of low temperature storage of bread to delay the aging of bread.
Methods to reverse the aging of bread and steamed buns:
Different types of bread and steamed buns must be matched with different emulsifiers, enzymes, humectants and other excipients.
Emulsifier + enzyme preparation + water retention + humectant, etc.
Du Dechun:
Ph.D., Chief Engineer, Bakery Process Technology.