Whey protein hydrolysates as prebiotic and protective agent regulate growth and survival of Lactobacillus rhamnosus CICC22152 during spray/freeze-drying, storage and gastrointestinal digestion

BACKGROUND Probiotic products are receiving increasing attention because of their tremendous beneficial health effects. However, it is still a great challenge to preserve probiotic viability during processing, storage and gastrointestinal digestion. Encapsulation is a widely known technology for enhancing bacterial viability and product stability. Hence highly hydrolyzed whey protein hydrolysate (HWPH) and moderately hydrolyzed whey protein hydrolysate (MWPH) used as a one-step culture medium and wall material for Lactobacillus rhamnosus were investigated. RESULTS H/MWPH-substitutive medium for the growth of Lactobacillus rhamnosus presented double the biomass production compared to other media. The H/MWPH-substitutive medium in combination with freeze drying also led to the highest survival ratio (97.13 +/- 9.16%) and cell viability (10.62 log CFU g(-1)). The highest survival rate of spray-dried cells was 85.56 +/- 7.4%. In addition, the cell viability of spray-dried Lactobacillus rhamnosus with MWPH as culture and dry medium was 0.79 log CFU g(-1) higher than that of HWPH. Images confirmed that spray-dried Lactobacillus rhamnosus in MWPH provided better protection and it showed greater sustained viability after gastrointestinal digestion. CONCLUSION Overall, WPH just as carrier provides better thermal protection and MWPH is a preferable two-in-one medium for probiotics. (c) 2022 Society of Chemical Industry.