3. Results and Discussion
3.1 Microstructure during cooling and storage
CLSM micrographs illustrating the time-dependent structure evolution of seeded and non-seeded pure
cocoa butter, cocoa butter and sugar and cocoa butter and cocoa particles are presented in Figure 1 and
are adaptations of what has previously been published in [15, 16]. The staining dye (BODIPY) exhibited
significantly higher affinity to the liquid cocoa butter compared to the crystals, thereby enabling the two
phases to be distinguished by negative contrast. Both the sugar and cocoa particles appeared as black
areas in the micrographs.
The structure formed during 60 minutes of cooling differed substantially between the two precrystallisation
techniques. All seeded samples in Figure 1 formed multiple nucleation sites, which induced
rapid growth of crystals within the first 15 minutes of cooling. The seeds were easily mixed in the
samples, which resulted in a homogenous microstructure, with small proportions of liquid fat trapped
within the fat crystal network. A more heterogeneous microstructure was observed in the non-seeded
samples which coincide with previous reports, where the microstructure of poorly tempered chocolate has
been investigated with various microscopy techniques [18-20]. The non-seeded samples containing cocoa