Abstract:
Three different methods, namely the condensation reflux method (RTSG), the high temperature and high pressure method (HTSG), and the enzymatic method combined with high temperature and high pressure (ETSG) were used to prepare turtle shell glue from the shells of Mauremys mutica. The amino acid composition, isoelectric point, gel strength, rheological properties, infrared spectrum, and microstructure of the turtle shell glues were analyzed. The results showed that the yields of RTSG, HTSG, and ETSG were 8.69%, 12.28%, and 12.80%; and the protein contents were 59.53%, 74.45%, and 77.57%, respectively. RTSG had the best gelatinization property of 93.29 g. The gelatinization points of the gels obtained using the three methods were 5.56 ℃, 4.76 ℃, and 5.47 ℃, and their melting points were 14.86 ℃, 14.33 ℃, and 14.71℃, respectively. At high extraction temperatures, the collagen subunits were decomposed, and the amino acid content was low, thereby affecting rheological properties. Amino acid analysis results revealed that the turtle shell glues extracted using the different methods had similar amino acid compositions. FTIR spectra showed that the turtle shell glues extracted using the different methods exhibited the characteristic vibration mode of collagens in the amide region, with slight differences. SEM results suggested that RTSG, HTSG, and ETSG all exhibit porous network structures, and RTSG has smaller and fewer voids, indicating a superior gel network. Therefore, different extraction methods affect the internal structure of the turtle shell glue by changing the protein and amino acid content, thereby affecting the gel strength, rheological properties, and other physical and chemical properties of the glue. The aim of this study was to provide a theoretical reference for the development and utilization of turtle shell glue.
