Glutathione‐enriched baker's yeast: production, bioaccessibility and intestinal transport assays

Aims A glutathione ( GSH ) yeast‐based biomass ( Saccharomyces cerevisiae ) was used to investigate GSH stability, solubilization during gastrointestinal digestion and GSH intestinal transport. Methods and Results A postgrowing procedure was applied to improve intracellular GSH yeast content. The presence of adenine ( ADE ) in the biotransformation solution ( CYS ‐ GLY ‐ GLU mixture) and alternatively, a glucose shot after 4‐h incubation, allowed to obtain cells containing about GSH 1·6–1·7% dcw (dry cell weight) (control 0·5%). Yeast samples were subjected to in vitro gastrointestinal digestion and absorption assays employing Caco‐2 and HT29‐MTX cell lines in different proportions (100/0, 70/30 and 50/50). Trials were also performed to verify intestinal cell viability. Conclusions At least 87% of ingested GSH is available in reduced form for intestinal absorption. In vitro GSH transport assays indicated that GSH is poorly absorbed (<20%). Nevertheless, studies in response to oxidative stress induced by H 2 O 2 demonstrated a protective role of the GSH ‐enriched biomass towards intestinal cell viability. Significance and Impact of Study An enriched GSH yeast‐based biomass has been obtained using a postgrowing procedure. Although GSH present in enriched yeasts is poorly absorbed by intestinal cells, this biomass showed an intestinal local protective effect, improving cells viability when a simulated oxidative stress was applied.