COMPARISON OF RHEOLOGICAL CHARACTERISTICS OF WINTER WHEAT CULTIVARS DETERMINED BY EXTENSOGRAPH AND ALVEOGRAPH

The rheological properties of seven winter wheat cultivars from two harvest years were studied. Rheological testing included two empirical rheological methods, alveograph and extensograph. Principal component analysis on the studied rheological parameters showed that the alveograph and extensograph parameters are influenced by entirely different factors. The first component was responsible solely for the extensograph parameters, primarily for the resistance properties of dough samples. The second component affected the extensograph extensibility (E) and alveograph tenacity (P) parameters as well, in spite of the fact that these parameters refer to different properties of dough. The third component explained only alveograph parameters, such as P, L and G values. The Pearson's correlation coefficients showed that the extensograph area parameter primarily depends on the maximum resistance to extension of dough (r=0.91). The extensibility and resistance at a constant extension of 5 cm properties did not show such strong relationship with the area parameter (r=0.56 and 0.65, respectively). The relationship between the extensograph maximum resistance and extensibility parameters was positive (r=0.20), while the correlation coefficient between alveograph P and L value was negative (r=0.34).