Principal component analysis of measured quantities during degradation of hydroperoxides in oxidized vegetable oils

Decomposition of hydroperoxides in sunflower oil under strictly oxygen-free conditions was followed by measuring peroxide values against time, absorba nce values at 232 and 268 nm, para-anisidine values, and by quantitative an alyses of volatile products using various additives. The results were arran ged in a matrix form and subjected to principal component analysis. Three p rincipal components explained 89-97% of the total variance in the data. The measured quantities and the effect of additives were closely related. Char acteristic plots showed similarities among the measured quantities (loading plots) and among the additives (score plots). Initial decomposition rate o f hydroperoxides and the amount of volatile products formed were similar to each other. The outliers, the absorbance values, were similar to each othe r but carried independent information from the other quantities. Para-anisi dine value (PAV) was a unique parameter. Since PAV behaved differently duri ng the course of hydroperoxide degradation, it served as a kinetic indicato r. Most additives were similar in their effects on the mentioned quantities , but two outliers were also observed. Rotation of the principal component axes did not change the dominant patterns observed. The investigations clea rly showed which variables were worth measuring to evaluate different addit ives.