Control of moisture in crackers is necessary
in order to optimize the quality of the product and the production
Too high a moisture content will adversely affect the texture
and taste, and also shorten shelf-life. Too low a moisture
content, results in crackers that damage easily, leading to
wastage both before and after packaging. Additionally low
moistures cause crackers to “burn” to a greater
extent when they pass through the ovens, leading to an undesirable
Moisture measurements can be made on or off-line. Online
measurements greatly improve efficiency; they eliminate the
need for routine laboratory moisture testing and provide an
instantaneous measurement so that necessary process changes
can be implemented sooner.
Off-line moisture measurements are simple, sample a greater
product area, and are quicker to effect than using Infrared
balances or oven tests.
Cracker Manufacturing Process
Mixed dough is fed into a laminator, the “sheet”
of dough passes under gauge rolls and into a rotary cutter,
scraps and re-workable material is fed back into the laminator.
The crackers continue through the oven and cooler, onto a
transfer conveyor, which transports them to the packaging
The sensor is usually located several feet down line from
the oven exit, whilst it might be useful to locate it closer
to the exit from the point of automatic control of the ovens/
inlet belt speed, it is not recommended, owing to the fact
that NIR measurements are essentially surface measurements
and a degree of equilibration needs to occur in order to obtain
a stable and meaningful measurement.
TThe Food Grade MCT 300 is designed to meet the strict hygiene
and safety requirements of a food manufacturing plant. It
is electro less nickel coated and houses a Kel F or sapphire
window. The MCT 300 is fitted with a sensor window air purge
diffuser to provide a positive pressure; this minimizes fouling
of the window, but does not eliminate the need for a routine
cleaning procedure. If ambient temperature is greater than
50 șC, air or water cooling of the sensor is recommended.