30E-17 |
Physicochemical property changes in hard wheat flour dough during resting as influenced by flour strength and mixing time |
Y. R. KIM, Food Science, Purdue University, 1160 Food Science Building, West Lafayette, IN 47907, P. Cornillon, Danone Vitapole, 15 avenue Galilee, Le Plessis-Robinson, 92350, France, and O. H. Campanella, Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907. Very limited amount of work has been reported on the effects of resting time on physicochemical properties of hard wheat flour dough. Interpretation of the fundamental rheological property changes of dough during resting is not consistent in literature. For better understanding of physicochemical property changes of dough during resting, it would be necessary to consider various factors, including flour type, mixing time, and the type tests. The objective was to investigate the effects of resting on rheological and NMR properties of hard wheat flour dough having different strength and mixing times Dough samples were prepared using selected strong and weak hard wheat flour in a mixograph mixer at different mixing times. Small and large deformation tests and NMR relaxation time measurements were performed during resting. After 30 to 45 min of resting, both small and large deformation tests showed that stiffness, measured by G* and maximum stress in small and large deformation tests, respectively, decreased gradually, probably due to stress relaxation. During the initial 30 to 45 min of resting, stiffness of optimally and overmixed dough increased, possibly due to re-polymerization of protein. This phenomenon was more obvious for strong flour dough, and was not observed for undermixed dough. Small and large deformation tests for undermixed dough did not match. However, comparing the stress growth curves during resting, the trends in the stress at which strain is relatively small were similar to G* in small deformation, suggesting that small and large deformation tests might be affected by different types of molecular interactions. Decreased water mobility during resting, as measured by NMR, was possibly attributed to increasing molecular interactions caused by prolonged hydration. It was found that the effects of resting on the physicochemical properties of hard wheat flour dough were different according to flour strength, mixing time, and the type of rheological tests.
Session 30E, Food Engineering: Rheology and texture
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