Abstract:
Given the limitation of practical application caused by the poor gel properties of single gelatin, guar gum (GG), and low acyl gellan gum (LG) were used to modify the brown cattle hide gelatin. Different polysaccharide-protein composite gels were prepared by changing the proportion of GG and LG added to gelatin. The texture properties, surface hydrophobicity, intermolecular forces, sulfhydryl content, low-field nuclear magnetic resonance, infrared spectroscopy, fluorescence spectroscopy, and scanning electron microscopy were studied. The results showed that the texture characteristics were significantly improved after adding two kinds of polysaccharide gels. Compared with single gelatin, with the increase of the proportion of LG in the system, the surface hydrophobicity decreased by 59.96%, and with the increase in the proportion of GG, the total content of total sulfhydryl increased by 30.49%. The intermolecular force was mainly manifested as the decrease of covalent bonds and the increase of hydrogen bonds between the proteins, indicating that GG promotes the expansion of proteins and LG promotes the aggregation of proteins. Infrared spectroscopy showed that After modification, the content of random coils in the secondary structure of the gel system decreased, while
β-sheets increased, leading to enhanced orderliness. After modification, the fluorescence intensity decreased, and the stability of the system was improved. When the addition ratio of GG to LG was 5:5, the fluorescence intensity decreased by 26.81% compared to the pre-modified condition. The microstructure showed that the addition of GG could make the three-dimensional network structure of the gel denser, and LG can promote the highly brittle hard skeleton. In summary, the weak characteristics of gelatin gel were effectively improved by GG and LG.