Photochemical destruction of color compounds in fruit juices

In this work the UV-visible irradiation is presented as a possible process for destruction of the polymeric compounds (melanoidins) presents in the fruit derivative juices. In order to study this process, apple, peach and lemon juices with different soluble solids content and different browning degrees were irradiated using a lamp that emits in the UV-visible irradiative spectrum. From the obtained data it was observed an increase of the brightness of juices with the irradiation time, being been able to describe this increase by means of a first order kinetics. As for the colorimetric parameters a* and b* it has been obtained that both decreased with the irradiation time, indicating with it that the effect that produces the irradiation is contrary to browning process. An increase in soluble solids and in higher colored polymers content leads to a smaller percentage decrease of the colorimetric parameters. (c) 2004 Elsevier Ltd. All rights reserved.