乳链菌肽对明胶-酪蛋白钙复合膜理化及抑菌特性的影响研究

Effect of Nisin on the Physicochemical and Anti-microbial Properties of Gelatin-Calcium Caseinate Composite Films

本研究将不同浓度的乳链菌肽添加到明胶-酪蛋白钙中,开发出一系列可生物降解的乳链菌肽-明胶-酪蛋白钙抗菌复合膜,并对其力学特性、光学特性、表面形貌、抑菌活性和保鲜效果进行分析。结果表明:加入乳链菌肽后,成膜液中的乳链菌肽等成分物质与明胶相互作用,导致复合膜的宏观和微观性能均有不同程度改变。随着乳链菌肽浓度的提高,复合膜的厚度和断裂伸长率逐渐增大;外观颜色变深;抗拉强度、水溶性和水蒸气透过系数逐渐降低;复合膜透光率的降低,对光的阻隔性能逐渐增强;对常见致食品腐败菌(尤其是革兰氏阳性菌)有明显抑制作用,且逐渐增强;原子力显微镜观测其表面粗糙程度逐渐增大,对冷藏肉的保鲜效果越来越好。因此,乳链菌肽-明胶-酪蛋白钙复合膜的开发在食品包装和保鲜等方面表现出潜在的应用价值。

In order to develop biodegradable gelatin-calcium caseinate composite films with anti-microbial activity, nisin solutions of different concentrations were added to gelatin-calcium caseinate and the mechanical properties, optical properties, surface topography, anti-microbial activity and preservation efficacy of nisin-gelatin-calcium caseinate composite films were analyzed. The results indicated that the interaction between gelatin and nisin resulted in various degrees of changes in the macroscopic and microscopic properties of the composite film. With increasing concentration of nisin, the thickness and elongation at break of the composite films gradually increased. The composite films containing nisin were darker in appearance and showed a decrease in the tensile strength, water solubility, and water vapor permeability. The light transmittance of the composite film was reduced, while the light-blocking properties increased gradually with increasing nisin content, as did the surface roughness observed by atomic-force microscopy （AFM）. The composite film exhibited an apparent inhibitory effect on food spoilage microorganisms （especially the gram-positive bacteria）. The inhibitory effect showed an increasing trend with the increase in nisin concentration. The efficacy of the composite film in meat preservation improved continuously. In summary, the nisin-gelatin-calcium caseinate composite film developed in this study has a potential application in food packing and preservation.