Crude fat, diethyl ether extraction, in feed, cereal grain, and forage (Randall/Soxtec/submersion method):...

Area of Science:

• Analytical Chemistry
• Agricultural Science
• Food Science

Background:

• Accurate crude fat determination is crucial for animal feed, cereal grain, and forage analysis.
• Traditional extraction methods can be time-consuming and labor-intensive.
• Previous studies validated the submersion method for meat products (AOAC Official Method 991.36).

Purpose of the Study:

• To collaboratively study a submersion method for crude fat extraction in animal feed, cereal grain, and forage.
• To evaluate the efficiency, speed, and solvent reclamation capabilities of the proposed method.
• To assess the method's suitability for AOAC Official First Action.

Main Methods:

• Crude fat extraction using diethyl ether via the Randall (Soxtec/submersion) method.
• Collaborative study involving 12 laboratories across four countries (US, Sweden, Canada, Germany).
• Analysis of 14 blind samples covering animal feed, cereal grain, and forage matrices.

Main Results:

• The submersion method demonstrated a significant decrease in extraction time compared to traditional methods.
• Within-laboratory relative standard deviation (repeatability) for crude fat ranged from 1.09% to 9.26%.
• Among-laboratory relative standard deviation (reproducibility) ranged from 1.0% to 21.0%.

Conclusions:

• The submersion method is efficient, reduces analysis time, and allows for solvent reclamation.
• The method shows acceptable repeatability and reproducibility for crude fat determination in the studied matrices.
• The method is recommended for adoption as AOAC Official First Action.