译 名：
Mixing stages distinguishing of steamed bread dough withchanges of gluten protein property and structure
作 者：
Liu Changhong;Du Yunhao;Wang Lutong;Zhang Huang;Wang Yuanhui;Henan University of Technology/National Engineering Laboratory for Wheat & Corn Further Processing;Henan University of Animal Husbandry and Economy;
关键词：
mixing;;physical properties;;food processing;;steamed bread dough;;gluten;;property
摘 要：
The changes of gluten property were studied during dough mixing in order to indicate different stages of dough mixing in steamed bread process. As a kind of typical wheat flour for Chinese steamed bread, the special first class flour was used as raw material in this experiment. A small-sized mixer was used as mixing machine to prepare the steamed bread dough.During the dough mixing, the contents of gluten, gluten index, disulfide bond and free mercapto group, hydrogen bond and hydrophobic force, the peristalsis recovery and hardness changes of the dough were measured and analyzed. As a very important factor on steamed bread quality, the gluten content and gluten index would observably influence dough's physical behavior, such as gas-holding capacity, elasticity and extensibility etc. The gluten construction and extension would relate to some intermolecular force, such as disulfide bond, free mercapto group, hydrogen bond and hydrophobic force and so on. As the factors determining the extensibility and gas-holding capacity of steamed bread, peristalsis recovery and hardness of dough should be taken as important basis of dough properties in different stirring period. The results showed that: In the mixing procedure, some dough properties would increase before the first stage and then decease at last stage such as gluten content,gluten index, disulfide bond content, hydrogen bonding, and hardness of the dough. On the opposite, some factors of the dough would rise after falling such as free mercapto, hydrophobic force and peristalsis recovery quantity. Compared with gluten content peak(8 min), the gluten index peak(6 min) was a little bit forward. And gluten quantity and quality could not absolutely match only one of the intermolecular forces(disulfide bond, free mercapto group, hydrogen bond and hydrophobic force). So the gluten formation should be decided by several intermolecular forces altogether. The hardness changes of dough would be similar to gluten index. According to the test result above and the product features of steamed bread, the dough mixing could be divided into 4 important stirring stages: 1) Material blending and water absorption period. In the beginning(original 4 min in this experiment) agitating, the dough would come into being, and gluten would start to form, and the hardness of dough was increasing; 2) Gluten forming period. In this period(4 min to 8 min in this experiment) agitating after the water absorption of flour and the formation of dough, protein would absorb much water and form gluten more and more,and the gluten content, hydrogen bonding and hardness would reach maximum, and the crude dough was becoming fine and smooth; 3) Gluten expansion period. In this period(8 min to 18 or 20 min in this experiment) agitating after gluten forming,the hardness of dough would decrease gradually, and dough peristalsis kept very low degree, and dough extensibility reached best state; 4) Gluten breaking period. Stirring over the gluten expansion(after 20 or 22 min), the dough would start to produce water, become sticky and soft, and the gluten content and hydrogen bonding would reduce quickly, and peristalsis would increase obviously. It was suggested that: If the dough need fermentation(first mixing in two times mixing process), the dough agitating should be kept in second period. And if the dough directly went to shaping and proofing stage after mixing, the best situation of dough should be in the third period.
