The recorded NMR data was post-processed using MestreNova software (Mestrelab Research, Spain). The spectrum was phase and baseline corrected, and the desired peaks were integrated to determine the area under the peaks. The signals of phenylalanine (6.9 -7.5 ppm), indicative of gelatin concentration, were used for normalization of the NMR spectra. The lysine methylene signals (2.8 -3.0 ppm) from both unmodified and functionalized gelatin spectra were integrated to obtain the corresponding peak areas.