The formulation of reduced fat chocolate has been of interest to the confectionery industry for a considerable time. It presents a challenge, as fat reduction strategies are often accompanied by poor quality of the formulated product due to an increased viscosity of the molten chocolate. This causes difficulties during processing and poor sensory properties of the final product. The addition of limonene to chocolates leads to fat reduced chocolates that are less hard and have a lower melt viscosity. This study was undertaken to shed light on the changes produced by the addition of limonene on the crystallization and microstructure of cocoa butter. Based on evidence obtained by X-ray diffraction, differential scanning calorimetry and polarized light microscopy, it is proposed that the presence of limonene enhances the production of lower polymorphic forms on cooling but accelerates the transformation to more stable polymorphic forms. This is demonstrated in the transformation of the a and b 0 IV forms in cocoa butter to form b V at early storage times (t = 0-1 week), and the transformation to form b VI at times [2-3 weeks at 20°C. There is a complex but marked effect on crystal size, mainly at early storage times.

Sunflower stearins obtained by the fractionation of high-oleic-high-stearic sunflower oil (HOHS) can be used for cocoa butter equivalents (CBE). The main objectives of this work were: (1) Compare the performance of two sunflower stearin-based CBE (palm-free and palm-containing) with commercial CBE and cocoa butter (CB) in terms of heat stability, hardness, and microstructure and (2) Test these sunflower stearin-based CBE in milk chocolate and compound-coating formulations to understand the evolution of their crystalline structure and the bloom development during storage. Sunflower stearin-based CBE exhibited different polymorphic behaviors, as well as a smaller and more compact microstructure than commercial CBE and CB. Although sunflower stearin-based CBE contain less-saturated fatty acids than commercial ones, they had more solids at high temperature and higher hardness and could work as a CB improver. On the other hand, the use of increasing levels of sunflower stearin-based CBE formulated and tested in this work on chocolate and compound-coating formulations favored a faster crystallization into a more stable polymorph, and influenced the bloom evolution of these confectionery products.

The isothermal crystallization kinetics and melting behavior of mixtures of tripalmitin (PPP) and triolein (OOO) were investigated using hot stage microscopy (HSM), with supporting differential scanning calorimetry (DSC) and NMR measurements. Some melting points determined via HSM and DSC were higher than predicted by the Hildebrand equation, but solid fat content melting profiles from NMR were close to ideal predictions. The observed deviations from ideal behavior with HSM/DSC could be attributed to concentration gradients in the liquid phase, rather than from nonideality. Sufficient time should therefore be allowed in melting experiments for diffusional equilibration to occurthe remelting time should generally be longer than the crystallization time. When crystallizing mixed PPP/OOO samples, two distinct polymorphs could be seen in the same “crystal”, with an outer ring of β′ surrounding an inner circle of β. Polymorphic transformation from β′ to β could be seen to occur via dissolution through a narrow liquid interface region between the two crystals. Growth rate data for β′ were proportional to the reduced saturation (or supercooling) calculated assuming ideal behavior. Growth rates of β via the solvent/melt mediated transformation of the β′ form could be related to driving forces based on the difference in solubility of the β′ and β forms.