不同蛋白质包埋壁材对益生菌在人体模拟胃液中的保护效果

为了提高益生菌在人体胃液中的存活率,本研究以大豆蛋白(SPI)、乳清蛋白(WPI)、酪蛋白(Casein)、明胶(Gelatin)为壁材,采用转谷氨酰胺酶交联的乳化凝胶方法,将Lactobacillus gasseri和Bifidobacterium bifidum包埋于蛋白质胶囊中,通过测定这两种益生菌在人体模拟胃液中的存活率,结果表明:相比于未经过包埋处理的细胞,包埋于蛋白质微胶囊中的细胞具有较高的存活率,并且还发现大豆蛋白微胶囊对菌的保护效果最好,明胶微胶囊最差。对于Lactobacillus gasseri,在加和未加胃蛋白酶的模拟胃液中,菌在这四种蛋白质微胶囊中的D值分别为:73.1、59.7、63.9、47.3min及246.6、240.5、220.0、90.2min。对于Bifidobacterium bifidum,在加和未加胃蛋白酶的模拟胃液中,菌在这四种蛋白质微胶囊中的D值分别为:31.7、24.2、22.7、18.7min和124.3、103.5、97.6、47.8min。除此之外,还比较了蛋白质的四种理化特性(乳化能力,凝胶强度,乳化稳定性、渗透性),其结果:乳化能力大小为SPI>Casein>WPI>Gelatin,凝胶强度大小为Gelatin>SPI>Casein>WPI,模拟胃液的渗透性大小为Gelatin>SPI=Casein>WPI,缓冲能力大小为Casein>WPI=SPI>Gelatin。通过上述结果可以推测蛋白质的缓冲能力与保护效果有很大的相关性,但缓冲能力并不是唯一决定因素,蛋白质其它的理化性质都有可能影响其保护效果。

Protective effect of various protein as coating material on survival of probiotics in simulated gastric juice

The probiotics,Lactobacillus gasseri and Bifidobacterium bifidum were encapsulated into microcapsules with four types of protein-based coating material,such as soy protein isolation(SPI),whey protein isolation(WPI),sodium caseinate(Casein),gelatin(Gelatin) through transglutaminase-induced emusification/gelation method.The survivability of microencapsulated cells in the four protein-based microcapsules was conducted in simulated gastric juice(SGJ) with or without pepsin.SPI-based microcapsules provided the best protection for microencapsulated cells in all treatments.As for Lactobacillus gasseri,in SGJ with pepsin,the D-value of encapsulated cells in these four protein-based microcapsules were 73.1,59.7,63.9,47.3min,respectively;in SGJ without pepsin,the D-value of encapsulated cells were 246.6,240.5,220.0,90.2min,respectively.As for Bifidobacterium bifidum,in SGJ with or without pepsin,the the D-value of encapsulated cells in these four protein-based microcapsules were 31.7,24.2,22.7,18.7min and 124.3,103.5,97.6,47.8min,respectively.Additionally,some physical properties of these proteins for difference in protective effect on encapsulated cells in SGJ without pepsin were aslo investigated.The result showed that emulsion stability was SPI>Casein>WPI> Gelatin;gel strength was Gelatin>SPI>Casein>WPI;permeability to SGJ was Gelatin>SPI=Casein>WPI;buffer capacity was Casein>WPI=SPI>Gelatin.It could be deduced that buffer capacity had great influence on the protective effect in low pH condtion,other potential reasons for difference in the protective effect include difference in permeability of protein gels,emulsion stability and gel strength can also affect the protective effect.