Effects of tannic acid on gluten protein structure, dough properties and bread quality of Chinese wheat.
BACKGROUND
The effects of tannic acid, which is present in many plants, on the structure of gluten proteins and the properties of dough and bread were studied. Tannic acid was added at levels of 0.01, 0.02 and 0.03 g kg(-1) during the dough-making process.


RESULTS
The added tannic acid acted negatively on disulfide bond formation but interacted with gluten proteins via other covalent bonds, as detected by UV spectroscopy and dynamic rheometry. Rheological properties and texture of the bread were measured by farinograph, extensograph and texture profile analyser. Texture analysis indicated little change in adhesiveness and resilience of the bread at all three levels of tannic acid compared with the control, but changes in hardness and chewiness of the bread made with added tannic acid indicated that tannic acid could delay bread staling.


CONCLUSIONS
The effect of tannic acid on flour and dough is different from that of other flour redox agents. It breaks down disulfide bonds but also has positive effects on dough properties and bread quality. Disulfide bonds are commonly considered to be the most important factor affecting changes in the quality of bread. However, this study presents the new concept that other covalent bonds can also improve the quality of flour and bread and uses this property to investigate new, safe and efficient flour additives.
Zhang
Li
L
China-UK HUST-RRes Genetic Engineering and Genomics Joint Laboratory, College of Life Science and Technology, Huazhong University of Science & Technology, Luoyu Road 1037, Wuhan 430074, China.
Cheng
Libao
L
Jiang
Lijun
L
Wang
Yuesheng
Y
Yang
Guangxiao
G
He
Guangyuan
G
D000975:Antioxidants; D001939:Bread / Q000032:analysis / Q000592:standards; D004220:Disulfides / Q000737:chemistry; D005433:Flour / Q000032:analysis / Q000592:standards; D005519:Food Preservation / Q000379:methods; D005983:Glutens / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013634:Tannins; D014908:Triticum / Q000737:chemistry*
D000975:Antioxidants; D004220:Disulfides; D013634:Tannins; D005983:Glutens