The ESR signals in silk fibroin and wool keratin under both the effect of UV-irradiation and without any external effects and the formation of free radicals.

ESR studies have been done on natural and UV-irradiated silk fibroins and wool keratins at the temperature range of -196 degrees C to 20 C. The intensities of ESR signals obtained from the irradiated samples at -196 C remarkably increase with respect to those of natural samples. While the signals mainly consist of triplet peaks at -196 C.