This part of ISO 23275 specifies a procedure for the quantification of cocoa butter equivalents (CBEs) in cocoa butter (CB) and plain chocolate by high-resolution capillary gas chromatography (HR-GC) of triacylglycerols, and subsequent data evaluation by partial least-squares regression analysis. NOTE The presence of CBEs in CB and plain chocolate down to a level of 0,6 % (fat content of chocolate assumed to be 30 %) can be determined by using the procedure explained in ISO 23275-1. Differences in the procedure of the two methods exist in the number of individual triacylglycerols used for data treatment and in the mathematical evaluation principle of the data. The presence of CBEs is detected by linear regression analysis applied to the relative proportions of the three main triacylglycerol fractions of the fat analysed. The amount of the CBE admixture is estimated by partial least squares regression analysis applied to the relative proportions of the five main triacylglycerols.