Characterization of common wheat flours (Triticum aestivum L.) through multivariate analysis of conventional rheological parameters and gluten peak test indices

- Wheat quality evaluation by rapid tests is still a challenge along the value chain.
- Conventional empiric rheology is time consuming and often requires large sample size.
- GlutoPeak is a new rapid test that measures gluten aggregation behavior.
- PLS multivariate regression allows to predict conventional indices using GlutoPeak.
- A rapid estimate of flour end-use can be gained using GlutoPeak + PLS.

The GlutoPeak consists in high speed mixing of a small amount of wheat flour (<10 g) added with water, and in registering a torque vs. time curve in a very short time (<10 min). Peak torque, peak maximum time, and energy values are calculated from the curve, and used to estimate the aggregation behavior of gluten. The information brought by the GlutoPeak indices is still difficult to interpret correctly, also in relation to the conventional approaches in the field of cereal science. A multivariate approach was used to investigate the correlations existing between the GlutoPeak indices and the conventional rheological parameters. 120 wheat flours-different for protein, dough stability, extensibility, tenacity, and strength, and end-uses - were analyzed using the GlutoPeak and conventional instrumentation. The parameters were subjected to a data exploration step through Principal Component Analysis. Then, multivariate Partial Least Squares Regression (PLSR) models were developed using the GlutoPeak indices to predict the conventional parameters. The values of the squared correlation coefficients in prediction of an external test set showed that acceptable to good results (0.61 ≤ RPRED2 ≤ 0.96) were obtained for the prediction of 18 out of the 26 conventional parameters here considered.