detect absorbance changes in the gelatin composition after
cross-linking. Figure 5 presents the percent transmittance
of nonirradiated and UV-irradiated gelatin-glucose gels for
wavelengths in the 190–1100 nm range. The peak centered at
approximately 280nm in the nonirradiated sample is potentially
attributed to a convolution of absorbance by phenylalanine
and tyrosine, which are present in small amounts [36].
FollowingUVirradiation, the peak centered at approximately
280 nm greatly increases in magnitude and another small
peak appears at approximately 475 nm. The reductions in
transmittance at 280 nm and at 475 nm were thought to
be related to the cross-linking mechanism. Because some
oxidation products of tyrosine absorb at around 475 nm, for
example, dopachrome and aminochrome [37], it was posited
that tyrosine oxidation was part of the potential cross-linking
pathway. The peaks at 280 and 475mm are still maintained
after soaking irradiates samples in heated water