Quantitative Indices of the Oxidizability of Fatty Acid Compositions

Abstract

The correlation between a wide range of fatty acid composition indices, resulted from different groups of purified edible oils and their binary blends, and two quantitative criteria of primary (induction period of hydroperoxide formation at 60 °C) and secondary (oxidative stability index, OSI, at 100 °C) oxidations was evaluated. On the basis of highly correlated linear regression models, a corrected form of calculated oxidizability index and the content of saturated fatty acids, SFA, were jointly found to be appropriate indices of primary oxidative stability of all vegetable oils whereas the ratio between palmitic and linoleic acids was mainly considered to show their secondary oxidative stability. As for the oils containing fish oil (FO), a combination of SFA/(C18:4 + C20:4 + C20:5 + C22:6), and monounsaturated fatty acids/(C18:2 + C18:3) ratios was used to represent the primary and secondary oxidative stabilities. Among the oils containing vegetable oils and even fish oil, canola oil, and its blends had the best fatty acid composition from a health point of view. Practical Application: Since edible oils have a vast diversity in fatty acid compositions of very different oxidative stability, prediction of oxidizability based on fatty acid compositions has become too complicated. Considering primary and secondary oxidation products over the course of lipid oxidation, the present study simplifies the prediction of the oxidative stability of fatty acid compositions by introducing four predictive linear regression models for vegetable and fish oils.Oxidative stability of five different edible oils and their binary blends are determined through the induction period (IP) of hydroperoxide formation and the oxidative stability index (OSI) at 60 and 100 °C, respectively. Considering a range of linear regression models between fatty acid composition indices and the oxidative stability quantities, IP and OSI, four linear regression models of highest correlation were obtained to simplify the prediction of oxidizability of diverse fatty acid compositions.