Double use of hyperconcentrated sweet whey: a novel strategy for production of [i]Propionibacterium freudenreichii[/i]
Résumé
Propionibacterium freudenreichii is widely used as cheese ripening starter. Its probiotic effects have also been reported at the gut level, including modulation of bifidobacteria, of colon epithelial cells proliferation and apoptosis and of intestinal inflammation. They rely on active metabolism in situ. Growth media and growth conditions determine stress tolerance acquisition in P. freudenreichii, thereby determining its probiotic efficacy in the final products. A simplified process from growth to spray drying of propionibacteria was developed using hyperconcentrated sweet whey as a 2-in-1 medium to both culture and protect P. freudenreichii from spray drying, without harvesting and washing step. The hypertonic stress in hyperconcentrated sweet whey led to overexpression of key stress proteins, accumulation of intracellular storage molecules, compatible solutes, enhanced multistress tolerance acquisition, as well as enhanced survival upon spray-drying. This work opens new perspectives for the sustainable development of new starter and probiotic preparations with enhanced robustness.