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 p-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 beta-glucosidase activity. Intracellular P-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 beta-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. (C) 2009 Elsevier Ltd. All rights reserved.