Fig. 68: Modern instrumental methods of cereal analysis

1. Introduction
For many years the cereal industry has been making efforts to predict processing quality as early, quickly and reliably as possible on the basis of commercial samples. Over the past few decades, analytical values obtained by indirect methods have been used more and more to complement or even replace the results of baking trials. Fig. 68 gives an overview of the most commonly used testing methods for characterizing wheat and rye for bread baking.

The purpose of this chapter is to give an insight into the routine methods in general use at the present time. The tests are carried out on cleaned sample material and fall into the categories of physical, chemical and rheological methods and standard and basic baking trials. Standard baking trials are those whose procedure and evaluation have been specified by established national or international organizations, i.e. they are standardized.

By basic baking trials we mean procedures that are not standardized but whose performance in the published manner is especially recommended so that they can be taken as a basis for further tests of one's own (Brümmer and Neumann, 2002).

Physical methods such as sifting and weighing determine sizes and masses. Drying and conductivity mainly give information on the moisture content, while ashing reveals mineral concentrations. In some countries these methods are used to determine levels in whole grains and also in milled products. Washing and swelling methods serve mainly to determine the (wet) gluten content and also the quality of the protein by means of the sedimentation value after Zeleny. Great progress has been made with the introduction of near-infrared techniques. In these methods, calibration of the instruments is extremely important for precision and comparability. In Germany this is offered as an on-line service by the Association of Cereal Research (AGF) in Detmold.

Chemical methods are used chiefly to determine the overall protein content. Other methods are either no longer usual (maltose determination) or have not yet been introduced (pentosan content).

Rheological methods play a major role (See Rheology ), and the more recent methods described here also complement mainly the rheological testing sector. This is a clear indication of the significance of rheological methods in the context of cereal analysis. The chapter does not deal with sensory methods. Their importance is still not fully recognized, although they involve very little work and the results they produce are very valuable and far-reaching.

As far as the indirect routine methods are concerned, their limitations and restricted ability to predict such aspects as baking properties have often been emphasized, and in fact correlation coefficients of r = 0.5 to 0.6 usually have to suffice in practice.

Modern Cereal Analysis by New Rheological Methods:



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