Cereals processing technology

170 Cereals processing technology
sensing is translating the dielectric behavior of the product (caused by its
moisture content) into moisture readings. Both of these methodologies are
highly developed, readily available, and backed by good service capabilities.
Color, likewise, is measured on-line by measurements of reflectance in the
red, blue and green bands of the spectrum. Then by using built-in computed
algorithms a numerical readout is given which translates to product color. In
both moisture and color measurements by instrument it is first, of course,
necessary to establish normal high and low acceptable limits through thorough
statistical analysis and product evaluations.
Bulk density may also be measured on-line. One such system employs a
computer-driven cup, which on system command, enters the product stream.
Then on retraction, the contents in the cup are leveled, and once fully retracted
into the machine, the net product weight is taken. Results can then be translated
into any desired units of bulk density.
I will leave it to others in other parts of this text to explain the present
availability and usage of automated machine analytical procedures of moisture,
protein, fat, fiber, and ash on raw grains. These would only be of limited value in
a very few breakfast cereal processes, since they are now common dependent
variables as they would be perhaps, say, in the flour milling industry. Standard,
approved laboratory analytical methods would be the preferred usage for
determination, and verification, of label nutrient declaration.
8.4 The future of the industry
The technology of the industry is running rapidly in the direction of computer
control of its total manufacturing systems. This is because of desired tighter
process control moving QC functions back onto the processing floor, and out of
a plant laboratory, relieving operators of repetitive tasks so they can concentrate
on more important areas, and relieving operations of relying on a few ‘expert’
operators.
The first steps were taken with individual process unit operations being
placed under PLC control systems. After material handling, which is namely on/
off conveyor control, the first major area was in ingredient weighing and
batching. Control of weighing major ingredients came first, but technology is
now available for weighing minor ingredients and liquids in very small
quantities, and with good accuracy. The Instrument Society of America has
published an industry standard (SP88) to address terms and concepts that should
be common for those writing software in this area. Weighing also addressed the
control of master ingredient and slave ingredient flows. Integrated PLC
operation performs beautifully in these instances.
Other individual unit operation functions put under PLC control were
cooking, cooling, drying, flaking, toasting, and coating. Temperatures,
pressures, processing times, gap settings, delivery rates, etc., are all examples
of variables moved from hard-wire, or human adjustment, to electronic control.