The number of testing methods for defining the characteristics of wheat flours is raising continuously, as a result of the striking necessity to anticipate their technological behaviour. The technological behaviour is the result of the subtle and complex interactions, which must be analyzed taking into consideration certain specific quality parameters: protein content, wet gluten content, the “strength” of gluten, the Zeleny indices, the falling number, extensibility, resistance etc.
The values endorsed in the literature for the classical parameters for flour quality (protein content, gluten index, wet gluten content, falling number) do not always ensure optimum technological behaviour. Certain studies explored the dependency of a few selected flour quality parameters of others. Additionally, the ways to predict parameter values as a function of monitored, known figures was researched. Anne Ingver and Reine Koppel demonstrated interesting correlations for the flour processed from the Estonian wheat, cultivated in the 1999 – 2003 period. Specifically, the researches focus in this case, on the linkages between physical and chemical parameters, extensografical and farinografical parameters, and the volume of the bread.
Gaines and colab. (2006) tested 33 wheat samples of some varieties cultivated in the United States. Three of the parameters taken into consideration were proven to be superior, with respect to predictability of technological characteristics: the alveografic mechanical work (W), the height of the mixografic peak and the capacity of retention of the solvents (Solvent Retention Capacity, AACC Method 56 – 11), against the gluten index ant the sedimentation indice SDS. Similar investigations have been made by Bettge and colab. (1989), Kostyukovsky and Zohar (2004), Rashed and colab. (2007).
Our research identifies, for the flours obtained from Romanian wheat, the correlations between main quality parameters – physical and chemical, alveografic and farinographic – in order to establish some predictive models for evaluating the value of some parameters, as a function of others.
One hundred flour samples of Romanian wheat, from the crops of the years 2005, 2006 and 2007 have been tested by determinating the main physical and chemical quality parameters (moisture, wet gluten, gluten index, protein, ashes, Falling number) and viscoelastic parameters, specifical for the alveografical method. We gave our results a mathematical simulation, in order to elaborate predictive models for estimating the value of the alveografic parameters – mechanical work (W), resistance (P) and extensibility (L) – based on main physical and chemical quality parameters. We describe two predictive multifactorial models, having the multiple determination coefficients (R2) bigger than 0.965, for each of the alveografic parameters.
As for the mechanical work (W), all the physical and chemical parameters of the flours, may be significant regressors for the predictive simulation of its value.
The extensibility (L) parameter can also be estimated, taken into consideration all the parameters, excepting the gluten index parameter, which is an insignificant regressor.
The alveografical resistance (P) can be modelled taking into consideration the parameters: Moisture, Protein, Falling number and ashes; the parameters Gluten index and Wet Gluten are insignificant regressors.
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