The effect of UV radiation on the values of thermal parameters of collagencontaining beta-carotene

Thermal parameters of collagen containing beta-carotene before and after UV irradiation were determined in air and nitrogen atmospheres. It was found that after UV irradiation of collagen and collagen containing beta-carotene , mass decrement, activation energy and entropy changes were changed and ma y give information about the phototransformations which occur in this prote in. However, these processes do not affect distinctly the values of onset t emperatures. Comparison of the derivatographic curves in air and in nitroge n suggests that oxidation of collagen may occur during heating of this prot ein and that this may also occur under UV irradiation. Smaller changes in t he presence of beta-carotene suggest that it makes collagen more resistant to the action of UV radiation. (C) 1999 Elsevier Science Ltd. All rights re served.