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“Spectroscopic and chemometric determination of functionality and baking quality of wheat”

As the title of my Ph.D. project implies, my field of research is to integrate three different areas in one thesis. Based on the fact that the whole chain from cultivation to consumption determines the quality of the end product, I focus on using the spectroscopic and chemometric methods, which best elucidate these relations in the production of wheat bread.

Spectroscopy: Using multivariate spectroscopic techniques such as near-infra-red (NIR) and infra-red (IR) spectroscopy, you are given a fingerprint of the chemical composition of the wheat samples. By the use of chemometrics, the spectra can predict the content of specific components such as protein, amino acid composition, baking properties and flavour or to choose sample material with sufficient variation for further chemical and rheological studies on cereal, flour, dough and bread. These measurements are made on many levels, from individual grains and gain samples to flour, dough and bread. Furthermore I study both low-field and high-field NMR in connection with a more thorough investigation of the chemical mechanisms behind the observed functionality and baking quality.

Chemometrics: To survey how the chemistry observed using spectroscopy and traditional chemical analyses of cereals, flour, dough and bread correlates with physical and sensory observations on dough and bread is only possible, when you have the right tools. Chemometric, graphic methods as principal component analysis (PCA) and partial least squares regression (PLS-R) are effective in finding the structure – the latent factors in big, complex data sets. Using an ordinary PC, large amounts of data are converted from a large number of samples measured with many variables to simple, comprehensible images, which relate to the innate structure in data. This explorative approach to the world is often the reason for hypotheses that could not normally be devised.

Wheat chemistry and functionality: The functional properties and baking quality of wheat depend on the chemical composition, which again depends partly on type and partly on cultivation conditions. In order to have an inductive approach and not be biased by hypotheses, I screene a large number of samles with large reciprocal variation in both gene material and cultivation conditions using spectroscopy. By the use of PCA I select samples which are significantly different and thus stretch the possible chemical variation in data. This is confirmed by chemical and physical measurements and are validated in relation to the already established knowledge – conceptual validation. To complete the study series, bread is baked from the flour, and a sensory analysis will partly substantiate the already obtained results, partly question the used quality parameters and partly make it possible to design a predictive PLS model for determination of sensory quality already at bulk level based on the large number of experiments.

Sampling: As all materials, thus also cereal, flour, dough and bread, have a innate heterogeneity, it is important always to be in full control of the sampling process and to know the size of the errors that occur in the research process. The biggest errors and thus also the reason for most of the noise in data are due to negligence of the significance of the way the mass of the sample is reduced before it is introduced in the analysis equipment. This part of the work is carried out in cooperation with Kim Esbensen, ACABS, Aalborg University Esbjerg.

The project is carried out in cooperation with Dept of Food Science, KVL. It is funded by an ordinary KVL scholarship. Main supervisor: Lars Nørgaard, KVL. Project supervisor: Anette Kistrup Thybo, DIAS.