Bioconversion of anthocyanin glycosides by Bifidobacteria and Lactobacillus

Eight strains of Lactobacillus plantarum, 6 strains of Lactobacillus casei, Lactobacillus acidophilus LA-5, and Bifidobacterium lactis BB-12 were screened for β-glucosidase activity. We then proceeded to investigate the enzymatic potential of selected strains for bioconversion of delphinidin and malvidin glycosides to their metabolites. L. plantarum and L. casei strains showed the highest cell-envelope associated β-glucosidase activity. Intracellular β-glucosidase activity from B. lactis BB-12 was up to 287-fold higher than that of the other strains. The L. acidophilus strain showed low β-glucosidase activity, both, intra and extracellularly. No aglycons were detected in bacterial extract reactions with anthocyanin glycosides. Delphinidin-3-glucoside underwent chemical degradation to form mainly gallic acid, although delphinidin-3-glucoside degradation due to B. lactis BB-12 and enzymatic activity towards chemically-formed metabolites due to L. casei LC-01 were observed. Incubation of malvidin-3-glucoside with B. lactis BB-12, L. plantarum IFPL722, and L. casei LC-01 cell-free extracts led to different patterns of gallic, homogentisic and syringic acid formation.