The rapid determination of fat in cocoa products by using a differential density technique

Abstract

The rapid determination of fat for process control purposes in cocoa powders, extrusion cakes and chocolate liquors has been accomplished by rapid extraction of the fat with tetrachloroethylene, followed by indirect determination of the density of the resulting solution by using a differential density technique. The difference in apparent weight loss, which is indicated by an aperiodic balance, between a plummet immersed in the fat solution and an identical plummet immersed in pure tetrachloroethylene is correlated with the fat content of the sample. The correction factor associated with batch-to-batch variations of solvent density required by previous density methods is eliminated. The method is simple to operate and produces results at 10-minute intervals, although 20 minutes are required to complete each determination.

For cocoa powders, 95 per cent. of the results obtained for the fat content by the differential density technique were within ±0·46 per cent. w/w of those obtained by a Soxhlet extraction method, but for extrusion cakes and chocolate liquors the confidence limits were slightly wider.