Classification of whole wheat flour using a dimensionless number

The rheological standards currently used for classifying refined wheat flour for technological quality of bread are also used for whole wheat flours. The aim of this study was to evaluate the rheological and technological behavior of different whole wheat flours, as well as pre-mixes of refined wheat flour with different replacement levels of wheat bran, to develop a dimensionless number that assigns a numerical scale using results of rheological parameters to solve this problem. Through farinograph and extensograph results, most whole wheat flours evaluated presented parameters recommended for bread making, according to the current classification. However, the specific volume of breads elaborated with these flours was not suitable, that is, the rheological analyses were not able to predict the specific volume of pan bread. The development of the Sehn-Steel dimensionless number allowed establishing a classification of whole wheat flours as "suitable" (Sehn-Steel dimensionless number between 62 and 200) or "unsuitable" for the production of pan bread (Sehn-Steel dimensionless number lower than 62). Moreover, an equation that can predict the specific volume of whole pan bread through this dimensionless number was developed.