Abstract: To improve the stability of Lactobacillus rhamnosus GG (LGG), LGG microcapsules were prepared using complex coacervation method. Meanwhile, the effects of four prebiotics, inulin, fructooligosaccharide, pullulan and stachyose on the properties of LGG microcapsules. The microstructure and thermal stability of LGG microcapsules were analyzed by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), respectively. The results showed that the addition of prebiotics had a positive effect on the performance of LGG microcapsules. After simulated gastrointestinal treatment, the viable count of microcapsules with inulin was the highest, 9.5 (lg(CFU/g)). Stachyose had the strongest protective effect on LGG microcapsules under bile salt concentration and high temperature. The viable count of microcapsules with stachyose was 8.7 (lg(CFU/g)) after treatment at 75 ℃ for 30 min. The storage stability of LGG microcapsules at a water activity of 0.75 was improved by the addition of fructooligosaccharide. DSC analysis showed that the addition of prebiotics improved the thermal stability of LGG microcapsules. The melting temperature of LGG microcapsules with stachyose was 172 ℃, but the addition of fructooligosaccharide reduced the melting temperature of LGG microcapsules. SEM analysis showed that the addition of prebiotics did not affect the structure of LGG microcapsules. This study provides a theoretical basis for future studies on the influence of prebiotics on the performance of LGG microcapsules.

Key words: Lactobacillus rhamnosus GG; microcapsules; prebiotics; stability; viable count