Triacylglycerols crystallization control

In many food products and even some processing operations, it is important to be able to control lipid crystallization to obtain the desired number, size distribution, polymorph, and dispersion of the crystaHine phase. In most foods, it is crystallization of triacylglycerols (TAG) that is most important, although, at times, crystallization of other lipids (i.e., monoacylglycerols, diacylglycerols, phospholipids, etc.) may also be important to product quality. 

Fat is mainly composed of triacylglycerol (TAG) molecules. These TAG are polymorphic, i.e., they can crystallize under several crystalline forms (2). To get a stable food at the end requires the fat to be crystallized in the stable polymorphic form to avoid possible further transformation. Cocoa butter does not form in the stable Form V by simple cooling. It needs a well-controlled thermal path, performed under shearing conditions, called tempering. This specific temperature program is necessary to first nucleate enough crystals and then only keep the Form V crystals and melt the other metastable ones. Shear is also required during this process to get sufficiently rapid and intense nucleation of the stable forms. 

Apart from work-softening, controlled crystallization of the milk fat in the fat globules of the cream is the most frequently applied method to reduce the firmness of butter, especially at lower (refrigerator) temperatures. Owing to the unique fatty acid pattern of the milk fat triacylglycerols, milk fat crystallizes in two... 

---