Micro method for rapid gravimetric determination of fat content in food after acid treatment

Gravimetric methods for the determination of fat contents after acid hydrol ysis yield reliable results, since the portion bound to proteins and starch is also included. The methods in current use are rather time and solvent c onsuming. For this reason, a simplified procedure was developed. The food s ample is heated with hydrochloric acid and toluene for both hydrolysing the matrix and extracting the fat in the same step. An aliquot portion of the organic phase is evaporated and the fat residue is weighed. The results obt ained for different kinds of foodstuffs are virtually the same as those fou nd by using official methods. In comparison, the micro method described has several advantages: Only 5 ml of organic solvent are required instead of 2 00 ml. The results are obtained within 1.5-2.5 h instead of 8 h. The time i nvolved in manual work is only 10 min instead of 1 h. The fat is isolated u nder mild conditions and can be analysed further with other methods. When c ompared to instrumental procedures for determining the fat content, the mic ro method needs only simple equipment which is anyway in current use in lab oratories. It is not liable to errors and interferences, can be applied to virtually all kinds of food and needs only small laboratory space.