Distribution of apparent activation energy counterparts during thermo - And thermo-oxidative degradation of Aronia melanocarpa (black chokeberry)

- Kinetics of Aronia melanocarpa oxidation is explained by probability distributions.
- A mechanism which involves anthocyanins through fast chemical reactions is proposed.
- Binomial distribution explains polyphenolic decomposition kinetics in studied system.
- Extrinsic characteristics of thermal curves indicate autocatalytic reaction features.

Kinetics of degradation for Aronia melanocarpa fresh fruits in argon and air atmospheres were investigated. The investigation was based on probability distributions of apparent activation energy of counterparts (εa). Isoconversional analysis results indicated that the degradation process in an inert atmosphere was governed by decomposition reactions of esterified compounds. Also, based on same kinetics approach, it was assumed that in an air atmosphere, the primary compound in degradation pathways could be anthocyanins, which undergo rapid chemical reactions. A new model of reactivity demonstrated that, under inert atmospheres, expectation values for εa occured at levels of statistical probability. These values corresponded to decomposition processes in which polyphenolic compounds might be involved. εa values obeyed laws of binomial distribution. It was established that, for thermo-oxidative degradation, Poisson distribution represented a very successful approximation for εa values where there was additional mechanistic complexity and the binomial distribution was no longer valid.