益生菌对发酵酸乳蛋白的影响

Effect of Probiotics on Proteins in Fermented Milk Products

为了对比传统乳酸菌发酵酸乳与添加益生菌的发酵酸乳之间的蛋白、pH4.6可溶性氮、氨基氮与游离氨基酸等含量,考察益生菌对发酵酸乳蛋白的影响,主要采用SDS聚丙烯酰胺凝胶电泳(SDS-PAGE)、反相高效液相色谱和超高效液相色谱的方法进行研究。结果表明:在以响应面优化后的最优生产工艺条件下制备的益生菌发酵酸乳中,αs2-酪蛋白、αs1-酪蛋白和β-乳球蛋白条带比较浅,其中添加植物乳杆菌的发酵酸乳所形成的条带最浅;而pH4.6可溶性氮、氨基氮和游离氨基酸的含量均有所增加,其中添加干酪乳杆菌的发酵酸乳增加显著。造成这些结果的原因,主要是由于添加益生菌后其本身所含有的蛋白酶降解了更多的蛋白质所致,此外由于不同益生菌在酸乳发酵过程中代谢活性不同,导致不同发酵酸乳中蛋白质的降解程度也有所不同。

In order to explore the effect of probiotics on proteins in fermented milk products, probiotics-fermented yogurt was compared with traditional lactic acid bacteria-fermented yogurt in terms of the contents of protein, pH 4.6 soluble nitrogen, amino nitrogen and free amino acids by SDS-PAGE electrophoresis, reversed-phase high performance liquid chromatography and ultra performance liquid chromatography. In probiotics-fortified yogurt under the optimal fermentation conditions established by response surface methodology, the protein brands of a^2-casein, αs1-casein and β-lactoglobulin were relatively shallower, and those in Lactobacillus plantarum-fermented yogurt were the weakest; in addition, the contents of pH 4.6 soluble nitrogen, amino nitrogen and free amino acid revealed an increase, especially a significant increase in Lactobacillus casei-fermented yogurt. These results may be due to the more protein degraded by the protease from probiotics. Moreover, different probiotics with different metabolic activities in the yoghurt fermentation process can lead to the extension of protein degradation.