The use of palm oil presents some technological problems, especially related to slow crystallization rate. In addition, the DAG content is related to quality of fruit palm. In this context, refined, bleached, and deodorized (RDB) palm oils from different regions of Brazil, Colombia, and Malaysia were characterized for fatty acid composition, TAG composition, solid fat content (SFC), isothermal crystallization by differential scanning calorimetry (DSC) and NMR, and content of partial glycerides. The levels of DAG found in the samples 01, 02, 03, 04, and 05 were 7.8, 6.0, 8.1, 7.3, and 8.5%, respectively. The results of SFC by NMR showed the great influence of DAG, showing an increase of SFC at initial temperatures in the purified samples and this increase is related to higher crystallization rate. The reduction of time induction in the isothermal crystallization by NMR showed that the effect of DAG is directly related to initial crystallization, while in samples with high trisaturated (SSS) content no change were noted. Furthermore, the absence of DAG suggested greater homogeneity of the sample crystallization in the isothermal by DSC. The use of all associated methodologies indicated that SSS TAG and DAG levels are decisive parameters, considering the crystallization aspects of fats.
The figure shows the isothermal crystallization of RDB sample (SAMPLE 01) and RDB sample without DAG (SAMPLE PURIFIED 01). It has been found that DAG change the crystallization rate, delaying the induction time of crystallization, due to the low level SSS in the sample.