Abstract: To improve its in vitro environmental resistance, Pichia kudriavzevii DS8-1, a strain with probiotic potential previously prepared by our research group from traditional fermented camel milk in Xinjiang, was microencapsulated by a piercing-solidifying method. Three types of microcapsules coated with goat milk, SAM, SAMF and SAMG, were prepared using sodium alginate alone and with added fructooligosaccharides (FOS) or galactooligosaccharides (GOS) as the wall material, respectively. Uncoated microcapsules (SA) with sodium alginate as the wall material were used as the control. The microcapsules were characterized by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Their tolerance to simulated gastric juice, release characteristics in simulated digestive juice and storage stability were evaluated. Besides, the effect of freeze drying on the survival of microencapsulated yeast cells was investigated. Results showed that the viability of lyophilized SAM, SAMF, and SAMG microcapsules was 7.16–7.67 (lg(CFU/g)). Compared with SA microcapsules, SAMF microcapsules could delay the release of yeast cells, improve the survival rate, and have stronger inhibitory activities on α-amylase and α-glucosidase after continuous exposure to simulated digestive juice. After SAMG microcapsules were stored at ?20, 4 or 25 ℃ for 30 days, the cell viability was higher than 7 (lg(CFU/g)). In conclusion, addition of FOS or GOS to sodium alginate and goat milk coating can be used to microencapsulate Pichia kudriavzevii with improved viability. The prepared microcapsules show promise as a delivery system for functional foods.

Key words: Pichia kudriavzevii; sodium alginate; fructooligosaccharides; galactooligosaccharides; goat milk