Differential Scanning Calorimetry and Fatty Acid Composition Analysis of Chocolates Marketed in Iran as an Alternative Method for Identification of Cocoa Butter Adulteration.

Abstract

Cocoa butter (CB), an expensive product containing a specific triacylglycerol (TAG)composition, is often the object of economic adulteration. The present study investigates the detection and quantification of cocoa butter substitutes (CBS) using differential scanning calorimetry. CBS was mixed with CB (from 0 to 100%) as standard samples and analyzed using differential scanning calorimetry and gas chromatography to evaluate the thermal characteristics and fatty acid composition respectively. Increasing the ratio of CBS/CB changed the thermal parameters and fatty acid profiles significantly. For quantification of CBS in commercial samples, medium melting fraction temperature (TMMFvia r2 = 0.922) and melting enthalpy (ΔHfvia r2 = 0.972) were successfully used to quantify the value of CBS in the samples suspected of being fraudulent. According to the results, all of the thermal parameters increased significantly (P < 0.05) with increasing ratio of CBS/CB. It can be attributed to the presence of saturated fatty acids (C12-C22) in CBS which increases TLMF. The promising results of the present study could be used as a tool for the fast identification of adulteration and quantification of CBS in chocolate compositions. Differential scanning calorimetry methods has been developed for identification of CB adulteration. CBS adulteration was detected in CB and also in commercial chocolate samples.