How A Moisture Analyzer Helps You Get What You Pay For

Quality control personnel across the food processing and packaging industry are guided by moisture content regulations and rely on a moisture analyzer to measure and record moisture content in their products.

Moisture content as measured by a moisture analyzer not only impacts the weight of what you buy but also the shelf life. Optimum moisture content helps keep sugar flowing freely, potato chips crunching crisply, packaged bread crumbs from becoming moldy and powdered bullion from hardening in the container all before their "use by" or "sell by" dates. Foods such as fresh fish and packaged poultry also have optimum moisture content, where too much equates to your paying for water instead of product.

Understanding Moisture Analyzers:

As stated above, optimum moisture content is determined through extensive testing with target amounts set and controlled by organizations such as the food and drug administration and industry trade groups. These tests are conducted in large drying ovens. They are time consuming but they do yield reference or target moisture content data.

After a products optimum moisture content is established it must be continually checked, confirmed and recorded right up to the point where the product is packaged for delivery to the supermarket. The technique used is called "loss on drying" or thermogravimetric measurement. Instead of using large drying ovens, technicians and quality control personnel use compact laboratory moisture analyzers.

Loss on drying is simply the difference in weight of a product sample when first placed on sample plates in the microprocessor controlled moisture analyzer and its weight after the drying cycle is completed.

Corn Flakes, for Example:

The drying is accomplished by halogen heaters mounted on analytical balances capable of readouts as low as 0.001 gram. Before analysis begins the correct moisture content parameters are programmed into the moisture balance. Using corn flakes as an example, the target moisture content is 9.7 dried at 248 F for 5 to 7 minutes. Next an empty sample plate and sample plate holder is placed on the balance and tared. Only then are ground corn flakes spread thinly and evenly over the sample pan and placed in the moisture balance for analysis to begin. Because relative humidity can affect moisture content samples being analyzed should be moved quickly from their bulk shipping containers to the moisture analyzer.

When the moisture analyzer is activated the halogen heaters immediately begin to drive off moisture. The process stops when weight loss levels off that is, no more moisture is being driven off. The moisture analyzer displays the resultant moisture content. This information can be recorded to a PC and printer for record keeping.

If pastes, liquids or slurry is being analyzed they are spread on a fiberglass filter or sandwiched between two filters for even distribution, to increase the surface area and to speed evaporation.
Because of the tremendous volume of product be in corn flakes or detergents being processed and packaged on a regular basis it is important that moisture analysis is performed quickly and at regular intervals. Versatile, precise moisture analyzers are tools that help packagers identify potential irregularities and minimize disruptions to packaging lines.