Colour Changes in Brandy Spirits Induced by Light-Emitting Diode Irradiation and Different Temperature Levels

One aged brandy was subjected to an artificial visible light source from light-emitting diodes (2 x 10(3) lx) and under dark conditions. The temperature was also controlled at 25, 35, and 45 A degrees C (+/- 2 A degrees C); the samples were monitored for colour changes; and selected chemical parameters were at 0, 10, 20, 30, and 40 days. Colorimetric indices, CIELab parameters and spectra were also determined with UV-Vis spectrometry. Visible light modified the colour of brandy and an important colour decrease was observed, showing maximum values (Delta E (ab)*) at 25 A degrees C, under the studied experimental conditions. On the contrary, at higher temperatures, significant colour degradation was not revealed. Non-colour parameters were not significantly affected by both irradiation and storage temperatures (p > 0.05). Kinetic parameters including rate constant and activation energy were calculated. Based on Arrhenius model, activation energies of a*, browning index and h (ab)* at darkness were 12.2, 55.1, and 21.6 kJ mol(-1) respectively.