Triacylglycerol composition, calculation

Figure 6. Triacylglycerol composition of reguiar sunflower oil as calculated from random distribution and experimentally determined (17). (Key Sat = saturated acid, 0= oleic acid, L = linoleic acid.)...

Formulae for calculating the triacylglycerol composition of interesterified fats are derived from probability considerations and a good exposition of the subject is given by Bailey (1951). Since every possible triacylglycerol has a chance of being formed, the number calculated from even a few fatty acids will be quite large and interpretation of oil properties difficult. 

Laurie acid incorporation. Laurie acid (50%) from the oil, administered to rats for 6 weeks, produced no significant difference between the experimental distribution of triacylglycerol types and the random distribution, calculated from the total fatty acid composition . 

The denominator for Equation E6.2 is calculated by performing steps 1 and 2 for all of the FAMEs present in a single triacylglycerol sample. The mole-corrected peak areas are added together to obtain the total of all mole-corrected areas. If we assume that the extent of conversion of free fatty acids to FAMEs is essentially quantitative, or at least equal for all fatty acids in our experiment, the above calculation leads directly to the combined mole percent composition of fatty acids in all positions of the triacylglycerol. 

The purpose of their investigation was to determine the relative order of elution of the molecular species of rearranged butterfat triacylglycerols for which the exact quantitative composition can be calculated by statistical considerations. The initial part of the study was concerned with verifying that a random distribution of the fatty acids had indeed been obtained, which was established by detailed GC and HPLC resolution and MS identification of the species. 

The composition of the randomised reaction mixture of triacylglycerols can be calculated by the number of triacylglycerols present. The number of triacylglycerols (taking into consideration positional isomers) is equal to rP + r )l2 and the number of triacylglycerols without positional isomers is (n + irP + 2n)l6. When 5 (6) acyls are present in fats, which is typical in triacylglycerol mixtures, the total number of triacylglycerols after randomisation is 75 (126) and 35 (56), respectively. 

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