COMPOSITION OF NATURAL FATS AND OILS 229 



Hilditch^"'^ concludes that the results obtained by esterificatioii of fatty 

 acids with glycerol or from interesterification experiments do not contribute 

 useful information explaining the behavior of enzymes in the living cells. 

 The chemical reactions involved required high temperatures and other 

 conditions incompatible with enzyme activity. 



At the present time, one cannot give a decisive answer as to whether tri- 

 glycerides are assembled exclusively according to a pattern of "even" 

 distribution or to one of random arrangement, or whether the animal fats 

 and vegetable fats are laid down in different patterns. The suggestion 

 that biohydrogenation accounts for the apparent random arrangement of 

 the fatty acids in some animal fats seems just as difficult to accept as the 

 hypothesis that differences in enzyme action may account for the varia- 

 tions in arrangement of the fatty acids in some animal fats as compared with 

 vegetable fats. 



(d) Theory of Partial Random Distribution. The most recent analysis of 

 the composition of corn oil by a modification of the Brown technic^^^ in 

 which 19 different fractions of the triglycerides were separated at low- 

 temperatures from acetone has convinced Doerschuk and Daubert-*^" that 

 neither the "even" distribution theory nor the straight random hypothesis 

 can account for the composition of the mixed and simple triglycerides ob- 

 served by them. 



Corn oil is composed chiefly of only 4 acids, and might therefore be ex- 

 pected to follow the "even" pattern closely. From the original kilogram of 

 corn oil analyzed, Doerschuk and Daubert^*** were able to account for 

 979.6 g. of total glycerides. The proportions of the fatty acids found in the 

 corn oil were 140.8 g. of saturated acids, 219.6 g. of oleic acid, 569.4 g. of 

 linoleic acid, and 5.88 g. of linolenic acid, making a total of 935.7 g. 



On the basis of a complete randomization, 40 different triglycerides 

 should be present as calculated from the expression (n^ + w'')/2, in which 

 n represents the number of kinds of fatty acids. However, since it is im- 

 possible to distinguish between the posilionally different glycerides, the 

 total number of constitutionally different triglycerides would be much less. 

 According to the formula (n^ + 3n^ -|- 2n)/6, one should be able to separate 

 20 constitutionall}^ different compounds without considering the isomeric 

 forms. 



If the "even" distribution pattern is the one followed in the case of corn 

 oil, only 6 triglycerides should be present. The number of triglycerides 

 w'ould thus be limited, because oleic and linolenic acids, as well as a satu- 

 rated acid, would not be expected to occur more than once, inasmuch as 

 thej' are present in an amount of less than 33% of the total acids. Lino- 

 leic acid might appear to the extent of either 1 or 2 molecules, since it is 

 present in an amount greater than 33% and less than 67% of the entire 



*» T. P. Hilditch, Fortschr. chem. organ. Naturstoffe, 5, 72-100 (1948). 



