Effects of Addition of 1,3-Dipalmitoyl-2-palmitoleoyl-sn-glycerol on the Physical Properties of Cocoa Butter and Fat Bloom Stability of Dark Chocolate

Fat bloom is a serious problem that occurs when chocolate and related products are stored at high temperatures for long periods. Various techniques have been used to retard and prevent the fat bloom phenomenon. In this study, we investigated the ability of a new type of symmetrical triacylglycerol, 1,3-dipalmitoyl-2-palmitoleoyl-sn-glycerol (PPoP), containing palmitic acid (P) at positions sn-1 and sn-3 and palmitoleic acid (Po) at position sn-2, to retard or prevent fat bloom formation. An XRD study of cocoa butter (CB) and TAG mixtures of CB/PPoP and CB/POP revealed that CB and CB/POP mixtures transformed into polymorphic Form VI under conditions where the storage temperature was gradually raised from 20°C to 28°C over a period of 100 days. In contrast, the XRD patterns of CB/PPoP mixtures after 100 days of storage was similar to that of Form V of CB, and unlike that of Form VI of CB. These results are the first to indicate that the adding PPoP may prevent or delay the polymorphic transformation of CB from Form V to Form VI. We also investigated the physical properties and fat bloom stability of cocoa butter equivalent (CBE) and dark chocolates made with different PPoP concentration and found that the solid fat contents of CBE decreased with increasing amounts of PPoP. the addition of PPoP tended to soften the dark chocolate. Finally, we found that the fat bloom formation of dark chocolate under thermal cycle storage conditions between 18°C-30.5°C and 20°C-32°C could be retarded by adding of PPoP. However, further studies are warranted to elucidate the PPoP-induced retarding mechanisms during the transition from Form V to Form VI.