Development of methods for the quality assessment of wheat and spelt

Context

Reference methods for the quality assessment of wheat have been used for several decades (eg Brabender Farinograph, Chopin Alveograph, Hagberg Falling Number, Zélény Index, …). Now, these criteria don't fit with the present needs of the cereal chain (breeding companies, elevators, milling and bread-making industries, …). These tests are indeed less and less able to discriminate and are not sufficient to sort out the best wheat for a given end-use. This is mainly due to major changes in wheat culture (improved cultivars, better nitrogen fertilisation, better ear fertility, higher seed weights). This led to higher yield with major changes in the maturation conditions of the crop which affected the composition and the technological properties of the grains. For these reasons, the different partners of the various wheat chain are looking for new tools to assess the wheat and to a lesser extend the spelt quality for a better fit with the end-uses.

Objectives

In this context the research activities of the "Cereal technology laboratory" are largely focussed on the development of new methods to assess the technological qualities of wheat grains and fractions mainly white flour for breadmaking. Beside the classical tests, these new methods contribute to the characterization of the varieties for the National Catalogue. These methods also contribute to the selection of new breeds of wheat and spelt.

Results obtained

The research is organised in main topics : 1) Development of a prototype for the quality assessment of wheat flours (rheology) A new instrument was developed for the estimate of rheological properties of bread making dough according to the response to the shear stress and to the raise of temperature (kneading plus a heating and cooling cycle). A ß-version of the prototype "Multigraph" will be soon commercialised by Chopin-Dubois under the name "Mixolab". The working procedures allow the analysis of white flours as well as entire ground material. It means that it can be used through the entire cereal chain up to producers and plant breeding companies. 2) Methods for a better understanding of the Starch – amylotytic enzymes interactions In close connection with the "starch project", the research work allowed a clear distinction between the contribution of the sole starch and the one of the amylolytic enzymes on the pasting properties of diluted flour solutions as measured with the Rapid Visco Analyzer (RVA). An AgNO3 2 mM solution was used as enzymes inhibitor for, on the one hand, the determination of the intrinsic pasting properties of the starch itself (according to its composition and structure) and on the other hand, for the determination of the viscosity drop due to a-amylase activities as measured by colorimetric methods like Amylazyme and Ceralpha (commercial kits by Megazyme). 3) Development of tests for the quality assessment of wheat prior to the harvest (unripe cereals). Since a few years, the Hagberg Falling Number is used in pre-harvest quality assessment of the wheat. Unripe ears are collected in the fields and brought to the laboratory for threshing. After oven drying, the Hagberg Falling Number is determined to estimate the physiological maturity of the crop in order to start the harvest at the optimum from the enzymatic point of view. Provided that the weather conditions are good, the enzymic activities remain stable. 4) Adaptation of classical methods for the quality assessment of wheat and spelt Classicaly, the Chopin alveograph measures the rheology of a dough on the basis of a constant hydratation (the water is added according tyo the moisture of the flour). The recent acquisition (october 2004) of a brand new alveo-consistograph instrument allows the determination of the water absorption (consitograph) and the determination of the dough rheology on the basis of a consistency (the water is added to reach a fixed consistency). This new approach can also contribute to the evaluation of the varieties within the National Catalog trials (D2) and for the development of new breeds (D3)

Contribution

see achieved results

Partners

Several CRA-W's Research Units take part in this project

The "Cereal technology Lab" collaborates with : • The "Food chemistry laboratory" of Prof J Delcour, KU Leuven, • The BIOT department of the Hoogeschool Gent, CTL, Prof M Eeckhout, Ing I De Leyn, • The Rheotec company, Markedaal – Belgium, Mr M. Aelvoet, • The Chopin-Dubois company, Villeneuve-la-Garenne, Paris-France, Mr A. Dubat.