Abstract
In the case of unhydrogenated natural oils and fats, it is well known that the configurations of polyz unsaturated fatty acids are almost so uniform that an accurate AOM stability is estimated from a fatty acid composition. The correlation of AOM value (POV=100) and fatty acid composition obtained in this study is as follows :
AOM (h) =600/Pu (1)
(Pu = diene percent + triene percent ×2) The equation of mixed oil with unhydrogenated oils derived from the equation (1) is as follows :
_??_ (2)
Where A1, Ai and An are AOM values of individual oils, and x1, xi and xn are weight fractions of them.
However, an unsaturated fatty acid composition of partially hydrogenated oil was very complex and an equation of AOM value and Pu was different from that of unhydrogenated oil. Rate of oxidation obtained under AOM condition showed three steps of a, b and c until POV reached to 100. It was understood that an intersection of a and c was approximately equivalent to AOM value. In the case of hydrogenated mixed oils, the same as the equation (2) was derived from the result, too. The AOM values of mixed oils calculated from this equation agreed finely with the values observed, except lard mixed.
