2. More Recent Rheological
Methods and Newly Developed Equipment
As we have said, rheological methods involve more work but are often
more relevant to the baking properties of the raw materials. There are several
conceivable ways of improving these existing basic methods. Firstly, the depth
and scope of the information yielded by the analyses can be increased, for
example by combination; secondly, the work required can be reduced or faster
and more reliable evaluations achieved by improving the software used for
calculation.
This chapter is mainly concerned with methods that are at the
development stage or currently being implemented in cereal laboratories. In no
way do we wish to question the important benefits and achievements of
established methods. The new developments should be regarded as complementing
the older procedures, and the basic testing plan for bread wheat or rye, for
example, is not likely to change in the near future.
2.1. Chopin Consistograph
The manufacturer has described important aspects in publications
(Dubat, 1999 and 2000). The device was developed on the basis of the Chopin
Alveograph Mixer and is fitted with a pressure sensor connected to a computer
for performing measurements and processing the results. The sensor measures the
pressure that builds up as the wheat dough forms during mixing. The mixing
paddle was modified as compared to the earlier Alveograph Mixer. Doughs mixed
in the Chopin Consistograph can then be tested further in the familiar manner
in the Alveograph. The stages of the preliminary test and the main test give an
overview of the procedure (Fig. 69).
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| Fig. 69: Stages of the preliminary test and the main test in the
Consistograph |
In comparative tests we compared water absorption values measured in
the Chopin Consistograph with those of the standard method using the Brabender
Farinograph and calculated a correlation of r = 0.64. Although the scatter is
still considerable, the positive impressions gained from the work predominate.
After some familiarization it is very easy to operate the device, including its
control unit and computer. In spite of the necessity for a preliminary test and
a main test, the overall measuring time is not very long. After the preliminary
tests the software shows the user the quantities to be weighed in and the
required amount of liquid directly.
2.2. Perten Shakematic 1090
(Automatic Shaking Device for Falling Number Analysis)
Perten Instruments has carried out intensive development work on new
instruments on the basis of ICC Standard Method No. 107/1, "Falling
Number", and the equipment required for the test.
A labour-saving device that has attracted too little attention so far
is the automatic sample mixer for rapid and uniform preparation of the
suspensions for the standard falling-number method of testing wheat and rye
meal and flour. Although it is a worthwhile aid to making up suspensions for
determining the Falling Number, it should be designed in such a way that larger
samples can be produced, for example for use in the Gluten Aggregation Test or
the viscosity test on rye. Unfortunately it is very slow to find its way onto
the market. But a similar instrument is already sold by NIRWeinard, Bad Viebel
(Germany).
Modern Cereal Analysis by New Rheological Methods:
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