生物甘油基聚酯对大豆分离蛋白复合膜贮藏期间机械性能稳定性的影响

以大豆分离蛋白（soybean protein isolate，SPI）为主要原料，将甘油进行改性后制备的生物甘油基聚酯加 入到成膜液中制备SPI复合膜，通过对贮藏期间SPI复合膜机械性能、水分含量和甘油迁出率进行跟踪测定，比较分 析甘油经改性后制备的增塑剂对SPI复合膜的机械性能稳定性、保水性、甘油迁出率稳定性及微观结构的影响。研 究结果表明：与未改性甘油增塑的SPI复合膜相比，改性后制备的机械性能稳定性最高的SPI复合膜为生物甘油基聚 酯（生物聚甘油和脂肪酸的质量比为1∶1）增塑的复合膜，其拉伸强度稳定性提高了18.08%，断裂延伸率稳定性提高 了34.52%，水蒸气透过系数稳定性提高了14.68%，水分含量稳定性提高了17.02%，甘油迁出率稳定性提高了74.28%， 膜体系的紧密性和连续性增强，且其表面形成了致密的空间网状结构。生物甘油基聚酯的添加一定程度上提高了SPI 复合包装薄膜的机械性能稳定性，为其更广泛的实际应用提供了重要的理论参考和技术支持。

Impact of Glycerol-Based Biopolyester on Mechanical Stability of Soybean Protein Composite Films during Storage

Soybean protein isolate (SPI) as a major ingredient was mixed with glycerol-based biopolyester prepared from modified glycerol to obtain SPI composite films, and changes in the mechanical properties, water content and glycerol migration rate of the resulting films during storage were monitored to investigate the effect of modified glycerol as a plasticizer on the film mechanical stability, water-holding capacity, glycerol migration stability and microstructure. The results showed that the composite films plasticized by a mixture of biopolyglycerol and fatty acid ratio (1:1, m/m) had the highest mechanical stability, and that of the tensile strength, extension at break, water vapor permeability coefficient, water content and glycerol migration rate increased by 18.08%, 34.52%, 14.68%, 17.02% and 74.28%, respectively, compared with the SPI films without unmodified glycerol. Moreover, the structure of the films plasticized by modified glycerol was more compact and continuous, forming a compact network on the surface. In conclusion, the incorporation of glycerol-based biopolyester could improve the mechanical stability of SPI composite films, which will provide the theoretical basis and technical support for broadening the application of SPI composite films.