2.5. Perten Falling Number Plus
With this new device, Perten has created an instrument with a wide
variety of applications. It will permit a great diversity of tests and analyses.
After studying this new development closely we can say that the device will probably
go beyond many of the questions answered by routine tests and therefore has capabilities
that will make it excellently suitable for research and development work.
The new measuring technique records three curves of different colours
for each of the two cylinders (Fig. 72).
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| Fig. 72: Measurement curves of the Falling Number Plus instrument (FN Plus) |
A red curve shows the relationship between the resistance of the
suspension and the rise in temperature, i.e. the viscosity behaviour of the
suspensions during stirring and heating.
An interesting point is the start of the viscosity increase, i.e. the
possible beginning of gelatinization. Here, a wider measuring range would probably
enable an even better correlation with the Brabender Amylograph values, for example.
A blue curve indicates the viscosity behaviour of a suspension over
the measuring period, i.e. it reflects the course taken by viscosity during the
test as a function of time.
A green temperature/time curve yields specific information, for
example on how, when and at what temperature of the suspension the recorded changes
occur. These can subsequently be related to other curves or values from other standard
methods.
In some cases, comparisons with established standard methods revealed
very close similarities (Lotte et al., 1999). For example, a correlation of r =
0.70 was found between the Perten gelatinization temperature and the maximum
temperature of the Brabender Amylogram, and the correlation between the Perten
FN Plus temperature and the maximum viscosity of the Brabender Amylogram was r
= 0.79. At r = 0.92 the result of the comparison between the Perten FN Plus
resistance and the Brabender maximum temperature was even better, although it
was not linear; this was also true of the correlation between the Perten FN
Plus resistance and the Brabender maximum viscosity (r = 0.86). Such results
permit the conclusion that the Perten FN Plus instrument might make it possible
to combine the information from determination of the Falling Number with that
of the gelatinization curves in one operation.
Here too, the control software offers many more options that were not
yet available in the prototypes. But besides these extended possibilities of evaluation
there are many variations on the individual steps that can be performed in order
to find answers to different questions.
These include variable temperatures for the water bath, so that
measurements do not necessarily have to be made at the boiling point of water
as in the standard Falling Number method.
The advantage of this was pointed out years ago (Both, 1978 and
Brümmer, 1984b). Moreover, the intensity (i.e. the number of up and down
movements of the Falling Number body) for making the suspensions can be altered.
For further research tests we recommend changing the current pH, for example by
adding buffers, acids or alkaline solutions.
The possibilities can probably be extended beyond the usual processing
of wheat and rye to other raw materials, ingredients etc., and analyses of end
products other than bread, small baked products and pastry goods are also
conceivable.
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