298 III. CHEMISTllY OF NEUTRAL FATS 



Table 43 



Synekgistic Effect of Citric Acid, d-Isoascorbyl Palmitate, and Phospholipids 



ON Antioxidant Activity of NDGA and (x-Tocopherol 



Keeping quality 



(active oxygen 



Substrate and antioxidants added method), hours 



Lard alone" 2 



+0.005% NDGA 12 



+0 .005% NDGA + .005% D-isoascorbyl palmitate 43 



+0.005% NDGA + 0.005% citric acid 48 



+0.005% NDGA (deodorized) 11 



+0.005% NDGA (deodorized) + 0.005% D-isoascorbyl palmitate. ... 41 



Prime steam lard alone'' 4 



+0 .06% D-isoascorbyl monoester 4 



+0.003% phospholipids 7.5 



+0 .03% phospholipids + .06% D-isoascorbyl monoester 26 



+0 . 12% D-isoascorbyl monoester 6.5 



+0. 12% D-isoascorbyl monoester + 0.03% phospholipids 44 



+0.001% a-tocopherol 4.5 



+0.001% a-tocopherol + 0.06% D-isoascorbyl monoester 7 



+0 .001%o a-tocopherol + .03% pho.spholipids 10 



+0.001% a-tocopherol + 0.03% phospholipids + 0.06% D-isoascor- 

 byl monoester 40 



+0.001% a-tocopherol + 0.03% phospholipids + 0.12% D-isoascor- 

 byl monoester 60 



° R. W. Riemenschneider, S. F. Herb, E. M. Hammaker and F. E. Luddy, Oil & Soap, 

 21, 307-309 (1944). 



^ R. W. Riemenschneider, J. Turer, P. A. Wells, and W. C. Ault, Oil & Soap, 21, 

 47-50 (1944). 



dogs, in amounts as much as 500 times the proposed level of consumption by 

 man.^*^"^ 



e. Synergists for Antioxidants. The use of synergistic agents to bolster 

 the effectiveness of the antioxidants has been a fairly recent development. 

 Thus, substances in this category will increase the activity of the natural 

 antioxidants in vegetable fats, and they will likewise decrease the amount 

 of inhibitol required to achieve the desired stability in animal fats. 



The mechanism of this synergism seems to have been fairly definitel}^ 

 proved with ascorbic acid. Its effect on the stabilization of milk fat was 

 shown by feeding it to cows^^'^-**^ or by its direct addition to milk.**^'^^^ It 

 is also used to prevent rancidity in mayonnaise.^*^ When tocopherol and 



"i-i H. J. Deuel, Jr., S. M. Greenberg, C. E. Calbert, R. Baker and H. R. Fisher, Food 

 Research, 16, 258-280 (1951). 



"2 W. C. Brown, L. M. Thurston, and R. B. Dustman, /. Dainj Sci., 20, 133-145 

 (1937). 



"' W. C. Brown, A. H. Vanlandingham, and C. E. Weakley, Jr., /. Dairy Sci., 22, 

 345-351 (1939). 



6" F. Kieferle and A. Seuss, Milchw. Forsch., 20, 23-38 (1939). 



5« G. M. Trout and E. C. Gjessing, J. Dairy Sci., 22, 271-281 (1939). 



6« P. J. Gray and I. Stone, Food Industries, 11, 626-628 (1939). 



