Cocoa butter symmetrical monounsaturated triacylglycerols: separation by solvent fractionation and application as crystallization modifier.

Abstract

Symmetrical monounsaturated triacylglycerols-also known as SUS (saturated unsaturated saturated triacylglycerols)-are the main triacylglycerols present in cocoa butter (CB), exhibiting decisive influence in the tempering process conditions and sensorial characteristics in chocolate products. CBs with lower amounts of SUS do not crystallize adequately in chocolate processing, generating a low quality product with higher susceptibility to fat bloom formation. In this context, fractions with higher contents of SUS triacylglycerols were obtained by solvent fractionation of cocoa butter, under four operating conditions varying crystallization temperatures (17, 18, 20 and 22°C) and sample/acetone solvent ratios (1:7 and 1:5, in w/v). After solvent evaporation, CB fractions were evaluated in terms of triacylglycerol profile, solid fat content and melting point. The solvent fractionation performed at 17°C with a 1:7 ratio of cocoa butter:acetone favored the separation of a higher concentrated SUS stearin (denominated as S17) with 7.1% increment in SUS triacylglycerols, mainly StOSt-1-stearyl-2-oleoyl-stearin (26.9%) and POSt-1-palmitoyl-2-oleoyl-stearin (45.0%). Additionally, S17 was added to pure cocoa butter at three different proportions of CB:S17 (95:5, 90:10 and 80:20, in w/w) and the blend was evaluated by isothermal crystallization (at 17.5°C) and consistency (at 10, 15 and 20°C). Compared to the pure cocoa butter, at 10°C, the blend with 20% stearin (80:20) showed an increment of 67% in the consistency and considerable higher crystallization rates at 17.5°C were found, confirming the potential contribution of the SUS triacylglycerols as crystallization modifiers of CB.