From growth to spray drying: two-in-one use of sweet whey to improve the biomass production and spray drying viability of probiotics
Résumé
Preservation of probiotic bacteria still represents a challenge as the market of probiotic products has been growing over the past decade. Among the different preservation techniques, spray drying has been recognized as an adapted technique to produce amount of dried probiotics at relatively low production cost, compared to freeze-drying. However, the challenge of producing probiotic powders by spray drying is primarily related to the existence of high temperature during process, which can damage bacterial cells and cause the reduction of their viability. In this work, a simplified process from growth to spray drying of two probiotic strains, Lactobacilllus casei BL23 and Propionibacterium freudenreichii ITG20, was proposed by using sweet whey as a two-in-one medium for growth and drying purposes. Interestingly, after increasing the TS of sweet whey from the original level of 5% to 30%, the two probiotic strains had higher final biomass production, instead of being inhibited by the high osmolality. The survivals of the probiotics after spray drying were also significantly improved when growing in media in the range of 20% -30% TS. Moreover, the probiotics in these powders maintained a considerably stable viability during 4 month storage at 4 ºC.