3种方法制备的龟甲胶的理化与结构特性比较

Physicochemical and Structural Characteristics of Turtle Shell Glue Prepared Using Three Methods

以石金钱龟龟甲为原料,采用冷凝回流法(RTSG)、高温高压法(HTSG)、酶法联合高温高压(ETSG)处理三种不同方法制备龟甲胶,对所得龟甲胶的氨基酸组成、等电点、凝胶强度、流变学特性、红外光谱、微观结构等理化性质进行表征。结果表明,RTSG、HTSG和ETSG的得率分别为8.69%、12.28%和12.80%,蛋白含量分别为59.53%、74.45%和77.57%;RTSG的凝胶特性最好(93.29 g);RTSG、HTSG、ETSG的凝胶点分别为5.56、4.76、5.47℃,融化点分别为14.86、14.33、14.71℃,提取温度高,胶原亚基组分被分解,亚氨基酸含量低,对流变性能产生影响;氨基酸分析结果表明,不同方法提取的龟甲胶具有相似的氨基酸组成;FT-IR光谱显示不同方法提取的龟甲胶在酰胺区都具有胶原蛋白的特征振动模式,具有微小的差异;扫描电镜显示RTSG、HTSG、ETSG都表现为多孔网络状结构,RTSG有更小和更少的空隙,有更好的凝胶网络。由此可见,不同提取方法通过改变龟甲胶的蛋白含量及氨基酸的多少影响龟甲胶的内部结构,进而影响龟甲胶的凝胶强度、流变学特性等理化性质,该研究旨在为龟甲胶开发利用提供理论支撑。

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.