StOSt-rich fats in the manufacture of heat-stable chocolates and their potential impacts on fat bloom behaviors

Abstract

Chocolate softening and fat bloom are the main defects in many tropical and subtropical markets. Incorporation of hard fats with similar triacylglycerol-type to cocoa butter, 1,3-distearoyl-2-oleoyl-glycerol (StOSt)-rich fats, is considered the most effective way to solve both problems. This review defines StOSt-rich fats based on the concepts of cocoa butter improvers and extenders, and further summarizes their potential sources, such as, mango kernel fat, illipe butter, sal fat, shea butter, kokum butter, algal butters and recombinant sunflower oils. Typical preparation techniques, including fractionation and esterification, are highlighted, with a clear focus on the improvement of StOSt levels by removing low-melting triacylglycerols and other interferants. Particular emphasis is given to the fat bloom formation in heat-stable chocolates formulated with StOSt-rich fats. The potential mechanisms in relation to compatibility between StOSt-rich fats and cocoa butter, dilution effects of low-melting triacylglycerols, and crystal changes affected by diacylglycerols are discussed as well. StOSt-rich fats consist of 30%–70% StOSt, 20%–60% low-melting triacylglycerols and 1.0%–7.2% diacylglycerols. Fractionation or sn -1,3 specific esterification is supposed to increase the StOSt levels as well as remove other components that may pose negative effects on chocolate structure. Mango kernel fats have attracted special interests because of the large amounts of kernels around the world, which have not been effectively utilized. Biotechnology and oilseed breeding are currently interesting technologies used to produce new StOSt-rich fats. Heat and bloom stabilities could be improved simultaneously by tailoring the StOSt-rich fats to suitable triacylglycerol compositions and diacylglycerol contents. • StOSt-rich fats are expected to solve softening and fat bloom defects of chocolates. • Exotic fats and recombinant vegetable oils are the potential StOSt-rich fats. • Fractionation and esterification could improve the purity of StOSt-rich fats. • Rapid fat bloom may occur in heat-stable chocolates formulated with StOSt-rich fats. • Eutectics, dilution effects and inconsistent crystal transition result in the bloom.