Process Sensors (Europe) Limited
Process Sensors

 Applications - Food

 

Why Measure?

Moisture is a key parameter in food processing as it directly impacts the product’s shelf life, texture, taste and appearance.  Moisture measurement is necessary to ensure the product is fit for sale, yet if this is undertaken once packaged, out of spec product will  not only result in wastage of product, but also of packaging materials and utilities.  On-line moisture measurement will enable adjustment of process parameters to achieve the target moisture.  On-line measurement of fat, protein and colour can be made simultaneously, and used for process control or food labelling purposes.
Facilities with multiple production lines will benefit from using the versatile bench-top moisture, fat, protein and colour analyser as an alternative to more laborious time consuming laboratory techniques.

 

Food Applications

Biscuits Dried fruit, vegetables and herbs Potato crisps
Breadcrumbs Flour – wheat, corn , soy Soup powder
Breakfast Cereals Flavourings Sugar
Casings Gelatin Tea
Chocolate, cocoa & drink powders Nuts Yeast
Chocolate Olive pumice/paste  
Coffee: green & roast beans, ground and instant Potato flake, granules, powder, starch  
Cheese Crackers Cheese Crackers Popcorn  
Dairy powders milk, casein, whey, lactose Salt  

Sensor
Depending on the ambient conditions, one of five sensor configurations can be selected:

  • Electroless nickel coated MCT 360-FG
  • High temperature compact s/s MCT 366
  • Robust waterproof MCT 330SF
  • Atex 22 MCT 360 for potentially explosive dust atmospheres
  • ExD MCT 360 for use in the presence of solvents

The multiplex sensor which incorporates a colour measurement in addition to one or more NIR measurements is available in any of the above except the Atex 22 configuration.

Note that the MCT 360FG, MCT 360-ATEX 22 and MCT 360-ExD are Smart Sensors for which a display unit is optional, but not essential. The other sensors require a separate processing unit which must be installed in a location where the ambient temperature is 50°C or lower.


Accessories


Various accessories are available to optimise product presentation to make measurement possible:
A sapphire sight window enables moisture measurement in incline chutes, hoppers and fluid bed dryers. A sample probe allows measurement of product under free-fall and a powder sampler provides a means of collecting product to reproducibly present product to the gauge for measurement.
Other options include a product loss sensor to hold the on-line moisture reading should there be a break in product and an alarm board to enable an alarm output if the measurement exceeds a high or low limit or if the gauge malfunctions.

A vortex cooler will ensure reliable continuous operation in hot locations( ambient temperature > 50°C) such as the exit of a fryer or oven.

Gauge outputs, Operator interface & Display

Up to 3 x 4-20MA or 0-10V
RS232 or RS485
Optional bus
Optional Operator Interface and display unit

The measurement


Measurement accuracy will depend upon the food under test and the constituent being measured. Homogeneity, consistency in composition and particle size, colour and presentation will all affect measurement accuracy.

Moisture measurement is the most accurate as NIR absorption at the measurement wavelength is strong, and the measurement wavelength isn’t too prone to interferences from other constituents.

Fat/oil measurements are typically accurate to +/- 0.3% absolute if referencing is accurate. Note that it isn’t possible to measure oil content as a % of the whole mass if oil is sprayed onto the product as it is obviously only present on the surface. In some instances it may be possible to correlate the gauge reading with the volume of coating applied, but frequently the presence of oil on the surface will render the gauge reading to be too noisy to be of practical use.

Protein measurements aren’t the most accurate on account that the protein absorption is very weak, so any changes in protein levels are reflected by very small changes in the gauge signal. This results in high span requirements. In addition there are also other close more strongly absorbing species which will interfere with the gauge signals. Finally, protein reference values provided as a result of chemical analysis aren’t always reliable.


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