CHEMICAL I'KOPERTIES OF FATS AND OILS 297 



vegetable oils than toward animal fats/^^ although the latter fats are also 

 protected if tocopherols or other inhibitols are added to them. The ac- 

 tivity is entirely in the cephalin fraction, and may be related to the ioniz- 

 able phosphoric acid in the phosphatidyl serine. ^^^ 



Green and Hilditch"^ and Hilditch and PauP^^ have reported antioxy- 

 genic activity in cereal and oil-seed flours, which can be only partially ex- 

 Iracted with fat solvents. It is stated that the enzyme catalase, which 

 speeds up the decomposition of hydrogen peroxide, may be a good stabili- 

 2;pj. 540 However, the effectiveness of liver as an antioxidant continues 

 after the disappearance of the catalase."^ The activity of cottonseed meal 

 cannot be ascribed to this enzyme.*-^ Finally, highly purified catalase 

 preparations were found to be ineffective in preventing rancidity in lard.^^s 



In spite of the very potent stabilizing effect of tocopherols and other 

 inhibitols on animal fats, they possess but little activity in the vegetable 

 fats from which they are derived. *^^ On the other hand, a number of acids 

 such as phosphoric, citric, and ascorbic acids have a considerable anti- 

 oxygenic action on vegetable oils,^^" while they are largely inactive in ani- 

 mal fats. However, since these acids are active only when inhibitols are 

 present, it is assumed that they exert a synergistic effect on the latter 

 compounds. The synergistic effects of the citric acid, phospholipids, and 

 D-isoascorbyl palmitate on the activity of such inhibitols as NDGA and 

 a-tocopherol are outlined in Table 43. 



Isopropyl citrate esters (predominantly mono-isopropyl citric ester), 

 in a vehicle consisting of a 1:1 mixture of mono- and diglycerides^"*^" and 

 stearyl citrate esters (predominantly distearyl citrate),^"" have recently 

 been shown to be especially effective in preventing the so-called "flavor 

 reversion" which may occur in refined limpid soybean oil or in hydrogen- 

 ated soybean oil. The isopropyl citrate esters in the mono- and diglycer- 

 ide vehicle are fat-dispersible, while the stearyl citrate esters are readily 

 fat-soluble. It is proposed that the isopropyl citrate esters plus vehicle 

 be used in margarine at a level not to exceed 0.02%, and the stearyl citrate 

 esters at a level of not more than 0.15%.^*^' No toxic effects could be 

 demonstrated when these products were administered to rats, rabbits, or 



"8 T. G. Green and T. P. Hilditch, /. Soc. Chem. Ind., 56, 23-26T (1937). 



"9 T. P. Hilditch and S. Paul, ./. Soc. Chem. Ind., 58, 21-24 (1939). 



"» M. R. Coe, Oil & Soap, 15, 230-236 (1938). 



"1 K. Taufel and R. Muller, Biochem. Z., 304, 275-284 (1940). 



"lo R. H. Neal, C. M. Gooding, and H. W. Vahlteich (to The Best Foods, Inc.), 

 U. S. Patent No. 2,485,631 (Oct. 25, 1949). 



B^if-C. M. Gooding, H. W. Vahlteich, and R. H. Neal (to The Best Foods, Inc.), 

 U. S. Patent No. 2,485,633 (Oct. 25, 1949). 



541c "Oleomargarine. Definitions and Standards of Identity. Notice of Hearing to 

 Amend Definition and Standard of Identity," Fed. Register, 16, 1640-1641 (Feb. 16, 

 1951). 



