Standard Oven Drying Methods vs TGM800: Direct Moisture Determination

TGM800 with open lidWorking with grains meant a lot of thermogravimetric analyses, but standard oven drying methods were incredibly time-consuming. Depending on the flour matrix, oven times could range from 1 hour to 17. Whole grains could take a full 72 hours. LECO Africa reached out to Jolanda Nortjé, Laboratory Manager of The Southern African Grain Laboratory (SAGL), with a suggestion of a better way, and Nortjé was happy to give it a try. She agreed to participate in a comparison of a primary moisture loss-on-drying determination using the TGM800 and standard oven drying methods.

Three types of grains were analyzed by SAGL in this comparison: whole sunflower seeds, maize meal, and flour (whole wheat and white wheat). These samples were production samples currently being analyzed by SAGL, so the results would demonstrate how applicable the TGM800 was to the actual work the laboratory was doing. The TGM800 and standard oven drying methods were performed on the same day for each type of grain to eliminate any variation from moisture loss during storage.

For the oven-drying methods, AACCI 44-15.02 Moisture in Maize Meal, ICC 110/1 Moisture in Whole Wheat Flour (2 hours), ICC 110/1 Moisture in White Wheat Flour (1.5 hours), and ISO665-2000(E) Moisture in Whole Sunflower Seeds were followed, as indicated in Table 1. The TGM methods used the settings found in Table 2.

Graph depicting loss-on-drying method parameters

Chart of TGM800 methods utilized in analysis

The SAGL found that the differences in average moisture between manual and automated methods using the TGM800 were on average 0.06%. The TGM800 was providing the SAGL with the same results as the oven drying methods.

However, the difference came with the analysis time. For the whole sunflower seeds alone, the oven drying method took 6 hours to complete.

In the TGM800, the laboratory had the results in 2 hours and 37 minutes. This was a time savings of 3 hours and 23 minutes for just two samples. The sunflower seeds’ results are displayed in Table 3.

Graph showing moisture analysis of sunflower seed samples

After the comparison concluded, Nortjé is budgeting to purchase the TGM800 for her lab. Not only was she pleased with the reliability of the LECO instruments she’s used in the past, but she also values our after-sales service and support.

After-sales service and support is in my opinion just as important decision making criteria as price.
-Jolanda Nortjé

See the full results from the SAGL’s comparison of the TGM800 and oven drying methods.