May 13, 1918 



Stability of Olive Oil 



363 



The close agreement of the calculated and the actual loss of iodin 

 numbers on the basis of linolic acid would indicate that probably only 

 linolic acid had been affected during the term of the experiment. The 

 matter will be considered further under iodin number (Table VIII). 



The decomposing action of air, light, and moisture on the unsaturated 

 acids of olive oil may also be measured by the loss in iodin number 

 (Table VIII. 



Table VIII. — Iodin number of the olive oil 



Conditions of the 

 experiment. 



Control 



Enzym-free 



Air 



Light 



Moisture 



Air-light 



Air-moifture 



Light-moisture 



Air-light-moisture. 



o 



83.45 



S3- 



83-9: 

 , [84. 00 

 .83.23 

 83. 91 

 83-97 

 83- 29 



-1-0. 

 + 0-39 

 +0-34 

 +0. 52 

 +0- 55 

 — o. 22 

 -l-o. 46 

 -l-o. 52 

 — o. 16 



83.05 

 82.87 

 82.52 

 82.84 



82.79 

 83- 15 

 80.84 



—0.40 



-0.58 

 —0.93 



— o. 61 



—0.28 



— 2. 6^ 



-0.66 



82.99 

 83.09 

 82.58 

 83.01 

 83-32 



79-49 

 82.66 



— o. 30 82. 95 

 — 2. 61 79. 80 





-0.46 

 -0.36 

 -0.87 

 -0.44 



-o. 13 



-3-96 



-o. 79 

 -o. 50 

 -3- 6s 



83.85 

 83.57 

 81.97 

 83.88 

 83.80 

 77-27 

 82.43 

 84- 17 

 •7- 29| 



+0.40 

 +0. 12 



— I. 48 

 +0.43 

 +0-35 

 -6.28 



— I. 02 

 -l-o. 72 

 -6. 16 



83.86 

 83-97 

 81. 17 

 83-99 

 83-81 

 75.31 

 81. 17 

 83. 99 

 75- 20 



+0.36 



2.28 



-8.25 



83. 88 

 83-73 

 79- 60 

 83.67 

 83.79 

 71.57 

 79.46 



84. 00 



+ 0.43 

 -t- 0.28 



- 3-8s 

 -f- o. 22 

 + 0.34 

 -11.88 



— 3-99 

 + 0-55 

 -11.68 



The control, enzym-free, light, moisture, and light-moisture samples 

 were not affected. Air and air-moisture caused considerable loss and of 

 substantially the same amount. Air-light and air-light-moisture were 

 equally effective and caused much greater loss than air or air-moisture ; 

 presumably moisture was a negligible factor in both instances. Air was 

 the principal factor, although greatly intensified by light. The loss in 

 iodin number was proportional to the gain in saponification number 

 evidently two different measurements of the same decomposition, as 

 shown by Table IX. The iodin number of linolic acid is 1 81.091. 



Table IX. — Character of the decomposition of the olive oil {igi6) 



Series. 



Conditions of the experiment. 



Loss in 



iodin 



number. 



Equiva- 

 lent to 

 linolic 

 acid. 



Equiva- 

 lent gain 

 in saponi- 

 fication 

 number. 



Actual gain 

 in saponi- 

 fication 

 number.' 



Air 



Air-light 



Air-moisture 



Air-light-moisture 



3-99 

 11.68 



Per cent. 

 2. 126 



6. 560 



2. 203 

 6.450 



4.254 

 13. 129 



4. 409 

 12. 909 



4. 72 

 13.04 



4- 13 

 13.21 



1 See Table VI. 



The formation of aldehyde as a result of oxidation was manifested by 

 the color imparted to the alcoholic potash in the determination of 

 saponification number (Table X). The fuchsin-aldehyde reagent (7^ 

 p. 15) was employed as a confirmatory test, but proved rather too 

 sensitive for the purpose. 



