Dimyristoylphosphatidylethanolamine (DMPE): A Potential Solution for Eliminating Chocolate Tempering

Previous studies have shown that adding dimyristoylphosphatidylcholine to chocolate can direct CB crystallization toward Form V. However, synchrotron microcomputed tomography revealed micro-cracks in the chocolate microstructure, attributed to packing imperfections induced at the nanoscale. These findings prompted the investigation of another phospholipid, DMPE, as a potential alternative to achieve form β-V crystallization without such defects.

In the first step of this study, CB was refined through degumming, neutralization, and bleaching (RB CB) steps. Then the effects of adding 0.1% w/w DMPC and 0.1% w/w DMPE on the crystallization kinetics of RB CB at 23°C and 28°C were evaluated. Adding 0.1% DMPE significantly accelerated the crystallization rate of RB CB at 28°C, which was subsequently chosen for further analysis. RB CB mixed with 0.1% w/w DMPC or DMPE was fractionated at 28°C for 24 hours, and the solid fractions were characterized for X-ray crystal structure, triacylglycerol composition, melting profile, and crystal morphology.

X-ray analysis revealed that only the RB CB solid fraction containing DMPE crystallized into the β-V triclinic form showing short-spacings at 4.6, 4.0, 3.9, 3.7, and 3.6 Å after 19 hours of storage at room temperature. Polarized light microscopy showed that the RB CB solid fraction containing DMPE exhibited smaller spherulitic structures, indicating a higher nucleation rate induced by DMPE. Differential scanning calorimetry thermograms revealed that the RB CB solid fraction with DMPE had a melting point of 36.2°C, compared to 34.7°C for RB CB alone and 38.2°C for the RB CB solid fraction containing DMPC.

Furthermore, chocolate formulated with 0.1% DMPE demonstrated delayed bloom development, maintaining a melting point of 34.4°C after one year of storage at 17°C. This study demonstrates that DMPE can induce the formation of the desired β-V form in chocolate without the need for tempering while maintaining stability over extended periods.