A comparison of the rheological properties of wheat flour dough and its gluten prepared by ultracentrifugation
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Ultracentrifugation has been used as a tool for separating dough into different phases and as dough can be described as a bicontinuous system, gluten forms one phase, and starch another. The aim of this study is to investigate the possibility of using ultracentrifugation to extract gluten from dough. By using this method disadvantages such as excess washing, drying and reconstitution of dried gluten (involving a second mixing) were avoided. Gluten samples were obtained by this method (doughs differing in water content from 42.6 to 47.1%) and the rheological properties of dough and the corresponding gluten were studied in frequency sweep. The gluten coming from dough after ultracentrifugation had water contents in the range of 54.2–58.8%. An increase in water content reduced the storage modulus to a greater extent than the loss modulus for the studied dough. The gluten was not affected to the same extent by an increase in water content, as was the dough. The ratios of G′dough/G′gluten and G″dough/G″gluten approached the value of 1 when the amount of dough water increased. The slope of log G″ versus log for gluten (n″gluten) were always higher than n′gluten. For dough the slope of log G″ versus log (n″dough) were on the same level or higher than (n′dough). It was concluded that both the frequency dependency and the values of G′ and G″ were more or less independent of water content for gluten. On the contrary dough showed a strong dependency of water content in particular for the value of G′ and the frequency dependency of G′.