Abstract :
[en] A multi-methodological approach was used to study the isothermal crystallization of cocoa butter (CB)
in the presence of sunflower oil based cocoa butter equivalents (CBEs). pNMR, DSC, oscillatory
rheology, XRD, and PLM were used for this purpose. All the techniques confirmed that at 20°C
isothermal crystallization of all the blends is a two-step process with formation of α crystals in the first
step and formation of β’ crystals in the second step. The blends with high amount of CBEs contained
more high-melting triacylglycerols (TAGs) and diacylglycerol (DAG) in compare with CB acting as seed
crystals enhancing the formation of a- crystals in the first crystallization step. Therefore, the induction
time of the first crystallization step was inversely related to the amount of CBE. In contrast, the
subsequent polymorphic transition was delayed by the presence of the CBE due to their low-melting
TAGs. However, adding up to 5% CBE did not change the Foubert’s parameters for isothermal
crystallization significantly. All the blends (except 5% HOSO CBE), had a mediated β’ crystallization.
Picturing of the microstructure showed that for the CB and the blends up to 50% large microstructures, indicative of the bV polymorph developed during storage. At 100%, a dense network of spherulites was formed at the beginning of the crystallization period, but upon further storage, no large morphological changes were observed.
Practical applications: In recent years, the production of CB has been delayed owing to its cultivation
difficulty and low yield due to pest attack, while the world cocoa prices have increased with rising demand and higher chocolate consumption. Therefore, there is a need to develop low-priced and appropriate alternatives to CB. Accordingly, in this study two sunflower oil based CBEs were produced with fatty acid mixtures in the presence of immobilized 1,3-regiospecific lipase. The results from this study could help the fats and oils industries to extend their knowledge on the crystallization and polymorphic behavior of two enzymatically produced sunflower oil based CBEs.
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