Nonenzymatic browning of selected fruit juices affected by D-galacturonic acid

This work studies the effect of D-galacturonic acid (AGA) on the non-enzymatic browning of three types of clarified concentrated fruit juices (apple, pear and peach). It was observed that the presence of AGA increases the browning of juices. This was evaluated by the evolution of the absorbance at 420 nm (A(420)) with the treatment time that these juices show. The evolution at A(420) over time was fitted to first-order kinetics and it was observed that the kinetic constant values increased with both the increase in the AGA content and the rise in the treatment. The effect of the temperature treatment on the non-enzymatic browning of these juices was quantified by fitting the variation of the kinetic constants with the Arrehnius equation, thus obtaining the corresponding activation energies. In the case of apple juice, it was observed that for the increase in AGA content the activation energy increases considerably, while for the pear and peach juices, a slight increase of the activation energy was observed with the increase in AGA.