There are three primary reasons for HIGH Crude Fat Results.
- The bag is not completely sealed such that sample gets lost during extraction.
- A bag picks up surface fat from another sample.
- Incomplete drying in the pre-extraction phase. This is the biggest contributor to high crude fat results. It is vital that all the moisture in the sample is removed before the extraction because the ANKOM technique uses the indirect method of determining fat (weighing what is left over after the fat has been extracted), It is a good idea to regularly check your moisture (dry matter) values when performing fat extraction using ANKOM instrumentation. This can be done by simply weighing and recording the weight of the Filter Bag prior to filling it with sample. After the 3 hour drying step, when you re-weigh the bags plus sample, the following formula will give you the moisture value:
100 x ((Filter Bag Weight + Sample Weight) - Weight After Drying) / Sample Weight
We would suggest each lab regularly test this analysis by utilizing a check sample or lab standard.
Low moisture values tend to be due to:
Not using or incorrectly using desiccant pouches
Incorrect oven temperature settings (100 - 105°C)
Hot or cold spots in the oven
The oven is being over loaded with other samples or glassware