Site-specific hydrolysis of chlorogenic acids by selected Lactobacillus species.

Hydroxycinnamic acids are a major group of phenolic compounds widely distributed in plants. Among them, chlorogenic acids and caffeic acid have been in the focus of interest due to their impact on food quality and their putative health benefits. Numerous microorganisms like lactic acid bacteria are able to hydrolyze chlorogenic acids by cinnamoyl esterase enzymes. Data on the specificity of theses enzymes regarding the cleavage of distinct isomers of mono- or dichlorogenic acids is lacking. Lactobacillus reuteri, Lactobacillus helveticus, and Lactobacillus fermentum were screened for their ability to hydrolyze chlorogenic acid isomers in culture medium. Concentrations of chlorogenic acids and the released caffeic acid were determined by UHPLC-ESI-MS. The highest hydrolysis rate (100%) was observed for the hydrolysis of 5-CQA by Lactobacillus helveticus. A so far unknown metabolic pathway for the cleavage of 4-CQA is proposed including isomerization to 5-CQA and 3-CQA followed by hydrolysis.