2.5.2 Chemical functional group analysis
In order to analyze the characteristic functional groups of the raw materials such as albumen, SA, gelatin, and the formulated A-SA-Gel hydrogel, Fourier transform infrared spectroscopy (FTIR) technique was employed using a Thermo Nicolet AVATAR 370 spectrometer. The spectra were recorded over the wave number range of 4000–800 cm-1 and the data were analyzed.