18 Quality Management
Moisture Determination of Meat Comparing
Automated Thermogravimetric and Air Oven
Loss-on-Drying Techniques
Authors: Jenifer Laurin1 (photo), Gabriela Schmid2,
Michael Jakob2, Lloyd Allen1
1 LECO Corporation, Saint Joseph, Michigan, USA;
2 LECO European Applications and Technology Center,
Berlin, Germany
Accurate determination of moisture in meat provides important
information related to the product’s quality and safety.
One of the most common moisture determination methods
is mass loss-on-drying utilizing an air oven. This technique
involves recording the sample mass before and after exposure to an
elevated temperature in an oven with air ventilation. The resulting sample
mass loss is calculated and represents the moisture content of the sample.
An official moisture in meat method, the AOAC method 950.46 was
used. This method utilizes the air oven loss-on-drying technique that is widely
performed in the food industry. The LECO TGM800 is an automated thermogravimetric
moisture determinator, which meets the standard requirements
for sample mass, oven temperature, and air flow, while providing additional
benefits. Specific advantages of the TGM800 include improved work flow
efficiency, minimal operator time, and a sample batch throughput of up to 16
samples. The instrument also incorporates automated end point recognition
based upon sample mass constancy, delivering optimal analysis times.
In this paper an interlaboratory comparison study is described between
TGM and AOAC results. Several methodologies, including decreased sample
mass and the addition of quartz sand to the sample, were investigated
to achieve improved precision and reduced analysis time.
The TGM800 is a thermogravimetric moisture determinator designed to
indirectly determine moisture content of materials using a mass loss-on-drying
technique. Mass loss of the sample is measured as a function of the oven
temperature by controlling the atmosphere and ventilation rate. The instrument
consists of a computer, an integrated four-place balance, and a multiple
sample oven that allows up to 16 samples to be analyzed simultaneously with
a maximum temperature of 175 °C.
Some key features:
• Supports 1.5 in diameter aluminum foil crucibles
• Supports 2.4 in diameter aluminum foil crucibles
• Analysis can be performed in air or nitrogen atmosphere
• Automated crucible and sample mass recording
• Optional fixed time or constancy method parameters
As samples were used chicken, beef and salmon, the interlaboratory study
was performed with the LECO laboratories in St.Joseph /Michigan and the
LECO EATC center in Berlin. Due to the nature of meat different but similar
samples, purchased locally, had to be used.
The objective of this paper was to demonstrate the analytical performance
and application capabilities of the TGM800 utilizing multiple method
parameters in comparison with the air oven method outlined in the
AOAC method.
Figure 1: TGM800 Figure 2: Sample carousel using 1.5 in
aluminum foil crucible (16 position)
Figure 3: Sample carousel using 2.4 in
aluminum foil crucible (10 position)