Studies on the crystal structure of many pure triglycerides by means of X-ray diffraction have been made by several researchers but on polymorphic crystal transformation of triglycerides, especially on fats, many problems are left.
Authors made researches in crystal transformation of plastic fats such as tallow, hydrogenated fish oil, binary system of tallow and hydrogenated fish oil, and cocoa butter by X-ray diffraction.
Based on the nomenclature by C.W. Hoerr, authors identified four crystal forms α, β' (beta prime), intermediate and β.
As tallow and hydrogenated fish oil take the crystal structure of β' and intermediate form, it is possible to determine the approximate proportion of β' form by comparing the intensity of diffraction band at 3.8A which is peculiar. As regards cocoa butter it takes α and β form, and the α directly transforms to β.
The proportion of β form, therefore, can be determined in similar manner.
Authors graphically presented the relation between transformation of polymorph and tempering of the plastic fats within 240 minutes.
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