FAT POLYMORPHISM AND CRYSTAL SEEDING EFFECTS ON FAT BLOOM STABILITY OF DARK CHOCOLATE

The effects of seeding with fine crystal powders on the physical properties of dark chocolate are reviewed in terms of the polymorphism and crystallization behavior of cocoa butter (CB) and of its major fat constituents. The polymorphic structure of four symmetric mixed acids saturated-oleic-saturated (Sat-O-Sat) triacylglycerols (TAGs) [POP (1,3-dipalmitoyl-2-oleoyl-glycerol); SOS(1,3-distearoyl-2-oleoyl-glycerol); AOA (1,3-diarachidoyl-2-oleoyl-glycerol); and BOB (1,3-dibehenoyl-2-oleoyl-glycerol)], and of tristearoyl-glycerol (SSS) are briefly explained. An attempt is made at replacing the currently used tempering method in the chocolate solidification process, by a simple cooling technique using fat seed crystals. CB (from VI), SOS (beta-1), BOB (pseudo-beta'), BOB (beta-2), and SSS (beta) are examined as seed materials. The addition of all powders accelerated the crystallization of dark chocolate. Fat bloom stability is also improved by the seed crystals, except with SSS. The effect is highly dependent on the physical properties of the seed material employed. The most influencing factors are the similarities in the polymorphic behavior between the seed material and cocoa butter, especially, chain length structure. Thermal stability of the seed crystal is also very important. In view of all physical properties examined, the present review concludes that the beta-2 form of BOB performs best as a seed material. In particular, it gives rise to an accelerated crystallization of form V of CB and moderates change in viscosity and antibloom effects after thermal incubation of dark chocolate below and above the melting point of CB.