May 13, 1918 Stability of Olive Oil 365 



gradually exceeded air-moisture and light-moisture, probably owing to 

 the difficulty of entirely excluding moisture and at the same time per- 

 mitting the entrance of air. Air-light effected more decomposition of 

 unsaturated acids and production of aldehyde than air. Light evidently 

 accelerated the action of air in this connection. 



Air-moisture had no action on color for three years, but eventually 

 exceeded air and equaled that of light in effectiveness. According to 

 the tintometer, for the last two years air- moisture has exceeded light and 

 light-moisture and has equaled that of air in destroying color. Air- 

 moisture effected rancidity the fifth year, exceeding air and light. Air- 

 moisture caused the formation of a slight amount of precipitate but no 

 appreciable turbidity until the fifth year. Air-moisture effected more 

 hydrolysis but the same amount of decomposition of unsaturated acids 

 and formation of aldehyde as air. 



Light-moisture was as effective in destroying color as light and more 

 active than air or air-moisture. According to the tintometer, for the 

 last two years light and light-moisture did not effect as complete destruc- 

 tion of color as air and air-moisture. Light-moisture caused the forma- 

 tion of more precipitate than moisture and a turbid oil. Light seemingly 

 was a factor. Light-moisture effected more hydrolysis than moisture 

 and as much as air-moisture. 



Air- light-moisture, like air-light, was the most active and effective in 

 destroying color and in producing rancidity, which was noticeable in the 

 second year. Air-light-moisture caused the formation of apparently the 

 most precipitate and a turbid oil. Air-light-moisture increased the 

 refractive index and viscosity of the oil substantially the same as air- 

 light. Air-light-moisture was the first to effect hydrolysis and exceeded 

 all others in amount. Air-light-moisture effected the same decomposi- 

 tion of unsaturated acids and production of aldehyde as air-light, which 

 greatly exceeded that of air or of air-moisture. 



PRACTICAL DEDUCTIONS 



From an economic standpoint air caused a slow destruction of color 

 in olive oil, the production of rancidity, and the decomposition of un- 

 saturated acids. 



Light caused an active destruction of color and a slow production 

 of rancidity. 



Air-light caused the most active and effective destruction of color, 

 active destruction of unsaturated acids, a rapid production of rancidity, 

 and a slow but marked production of free fatty acids. 



Moisture caused the production of a precipitate, a turbid oil, and 

 free fatty acids. 



Air-moisture practically duplicated the effect of air plus that of 

 moisture, and light-moisture that of light plus that of moisture. 



