The Determination of Wheat Breadmaking Performance and Bread Dough Mixing Time by NIR Spectroscopy for High Speed Mixers

A non-invasive near infrared (NIR) technique has been used to identify changes in the development of bread dough during mixing. A Perten DA-7000 Diode Array NIR instrument with a fibre optic probe attachment was used. Both breadmaking and biscuit making varieties of wheat were examined. Doughs were mixed using a laboratory scale Chorleywood Bread Process (CBP) mixer and NIR spectra were gathered (one every 2 s). Flour quality data were used to determine the relationship between NIR and breadmaking quality attributes and to study varietal differences in breadmaking performance. Instrumental and sensory techniques were used to establish the important quality attributes of commercially and laboratory produced bread. NIR spectra and mixer torque were measured at different mixing times to obtain an overall picture of the mixing process from the initial hydration of the flour particles through optimum dough development until overmixing had occurred. Loaves were produced and assessed for volume by seed displacement and crumb structure using an image analysis technique. The dough elastic modulus was measured at a range of mixing times using a Bohlin VOR Rheometer. Comparison of results from the NIR spectra, dough properties and bread quality was carried out. Results revealed a relationship between the rheological properties of dough and the final quality parameters of bread. NIR was shown to have considerable merit in following dough changes during mixing which were related to final bread quality and thus has the potential to be used as an on-line method for controlling breadmaking mixers.