Correlation of the fractal enzymatic browning rate with the temperature in mushroom, pear and apple slices

Abstract

A Fractal Kinetic method was applied to characterize enzymatic browning activity in samples from mushrooms, pears and apples. In this study, three independent repetitions were fulfilled to describe enzymatic browning kinetic by using two colorimetric methods: (1) the Mean method, when calculating an averaged intensity color (L* value) and assuming that colors are distributed homogeneously on the fruit surface during browning, and (2) the Fractal Kinetic method, that describes a non-homogenous color distribution on the food surface during the reaction. Samples of apples (‘Gala’), pears (‘Pack- ham’) and mushrooms (Agaricus bisporus) were cut and stored at four different temperatures (i.e., 5, 15, 25 and 35 C). Four environmental test chambers, all equipped with a computer system vision, were used. The images were photographed every 15 s during a period of 4 h and saved as a Tiff Format. The results of this study showed that the enzymatic browning kinetic rate was higher when the Fractal Ki- netic method was applied. The Arrhenius Law and the log-logistic model were applied in order to establish a relationship between the enzymatic browning rates and the temperature reactions. The re- sults revealed that the Arrhenius law can also be applied when using the Fractal Kinetic method.