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Crude and total fat determination in a feed sample by Soxhlet

Determination of crude and total fat in a feed sample by Soxhlet extraction according to the European Directive EC No. 152/2009
Crude and total fat determination in a feed sample by Soxhlet extraction

A simple and reliable procedure for the fat determination in feed products is introduced. This Application Note follows the official method EC No. 152/2009 from the Official Journal of the European Communities. The directive includes both direct extraction (crude fat) and extraction after acid hydrolysis (total fat). Which of the two procedures is used depends on the nature and composition of the sample:

Procedure A — Directly extractable crude oils and fats

This method is applicable to feed materials of plant origin, except those included within the scope of Procedure B.

Procedure B — Total oils and fats

This method is applicable to feed materials of animal origin and to all compound feeds. It is to be used for all materials from which the oils and fats cannot be completely extracted without prior hydrolysis (e.g. glutens, yeast, potato proteins and products subjected to processes such as extrusion, flaking and heating).

Interpretation of results: In all cases where a higher result is obtained by using Procedure B than by Procedure A, the result obtained by Procedure B shall be accepted as the true value.

Both procedures are described in this Application Note.

The directive EC No. 152/2009 requires an extraction time of 6 h. This Application Note shows by means of a certified reference material sample that an extraction time of 2 h is sufficient to receive reliable and reproducible results for crude fat as well as total fat using the FatExtractor E‑500 SOX.