Kinetic models to understand the coexistence of formation and decomposition of hydroperoxide during lipid oxidation.

Theoretical and empirical models about the coexistence of formation and decomposition of hydroperoxide during lipid oxidation under Rancimat conditions were established, verified and compared in this research. Theoretical models were proposed based on the simplified three steps of free radical chain reactions by solving kinetic differential equations, giving both formation and decomposition equations. Empirical models were modified from former phenomenological equations by eliminating the parameter of inflection time. Two groups of equations were both well verified by 93 sets of experimental data with adj-R2 of 0.9585-0.9967 and 0.9431-0.9977. Theoretical models were only suitable for the accumulation period of hydroperoxide, while empirical models were able to describe the whole process but give the inappropriate formation and decomposition equations. The further applications of models in quantitatively defining oxidation stages (lag, exponential and stationary phases) and re-evaluating the total oxidation value (TOTOX' = 2.27*PV + AnV) were also introduced.