Improvements of Modified Wheat Protein Disulfide Isomerases with Chaperone Activity Only on the Processing Quality of Flour
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- 作者：Guang Liu ; JingJing Wang ; Yi Hou ; Yan-Bo Huang…
- 关键词：wPDI ; Site ; directed mutagenesis ; Alkylation ; Wheat flour ; Wheat protein ; Bread quality
- 刊名：Food and Bioprocess Technology
- 出版年：2017
- 出版时间：March 2017
- 年：2017
- 卷：10
- 期：3
- 页码：568-581
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Food Science; Chemistry/Food Science, general; Agriculture; Biotechnology;
- 出版者：Springer US
- ISSN：1935-5149
- 卷排序：10
文摘
Wheat protein disulfide isomerase (wPDI) with oxidoreductase activity, isomerase activity, and chaperone activity catalyzes the formation of disulfide bonds in gluten in vitro; the addition of wild-type wPDI weakened yet the flour processing quality. To develop the potential flour improvers from wPDI, the modified wPDIs were prepared by the biological or chemical method, and their effects on the processing quality of flour in connection with bread making were investigated by farinograph, texture profile analysis, electrophoresis, size exclusion chromatography, and scanning electron microscopy. A truncated protein of wPDI, fragment AB with oxidoreductase, and isomerase activities only was firstly confirmed to exert deteriorative effects similar to wPDI on the dough and bread quality. Then other two modified wPDIs, mPDI and aPDI, were prepared by site-directed mutagenesis and alkylation, respectively. Both mPDI and aPDI considerably retained the chaperone activity of wPDI but completely lost oxidoreductase and isomerase activities. After adding the appropriate amount of mPDI or aPDI, the stability time of dough was significantly prolonged from 3.60 to 4.15 or 4.13 min, respectively. The enhanced gluten network matrix and decreased hardness and chewiness of bread further suggested that dough was strengthened by the treatment of mPDI or aPDI. Moreover, the formation of gluten network was facilitated by the modified wPDIs with chaperone activity only for the increase amount of gluten macropolymer and the decrease content of SDS-soluble gluten. Consequently, mPDI and aPDI are valid candidates of flour improvers in food industry.