This method quantifies the amount of crude fat in cereals, cereal-based products, and animal feed stuffs using acid hydrolysis followed by a Randall modification of the standard Soxhlet extraction. The acid hydrolysis process refluxes the sample with 4 N hydrochloric acid. The sample then undergoes the extraction process which includes submerging the sample into boiling ethyl ether and then lowering the solvent below the sample for a continuous flow of condensed solvent. The solvent is evaporated and recovered by condensation. The resulting crude fat residue is determined gravimetrically after drying. The method has a detection limit of 0.25 %.
NOTE: Most cereals, as well as feeds of animal origin, yeasts, potato protein, compound feeds with milk products, glutens, and products subject to processes such as extrusion, flaking, and heating, yield significantly higher total fat contents when pretreated using acid hydrolysis. This procedure is not applicable to oilseeds and oleaginous fruits.
Sample amount requested: 50 g
Questions concerning limited sample size can be answered by the UC Davis Analytical Laboratory.
ISO 11085:2015 Cereals, cereals-based products and animal feeding stuffs – Determination of crude fat and total fat content by the Randall extraction method
