Lactic acid bacteria decarboxylates p-coumaric acid in the presence of blueberry anthocyanins, facilitating hydroxyphenyl-pyranoanthocyanin formation

Abstract

Anthocyanins (ACNs) can react with hydroxycinnamic acids to produce a more stable chromophore called pyranoanthocyanin (PACN). Some lactic acid bacteria (LAB) strains decarboxylate hydroxycinnamic acids into 4-vinylphenols, more efficient cofactors for PACN production. This study evaluated p-coumaric acid decarboxylation by LAB in the presence of blueberry ACNs to favor PACN production. Highbush blueberry ACN and p-coumaric acid (1:3 ratio) were incubated for 24 h at 32 °C followed by 48 h at 45 °C in the presence of select LAB strains. Phenolic composition (HPLC-PDA, HPLC-PDA-MS/MS), spectra (380-700 nm), color (CIELAB), and pH were monitored every 24 h. The three LAB strains tested decarboxylated p-coumaric acid within 24 h. ACNs, PACNs, and intermediate compounds were detected at 24 h. By 72 h, PACNs were the only pigments detected, with yields <15%. Solution had higher hue angles (from ∼2° to ∼45°). Blueberry ACNs structure affected PACN formation, with malvidin-hexosides being more abundant.

Keywords: 4-Vinylphenol; Enzymatic decarboxylation; Food colorants; Highbush blueberry; Hydroxycinnamic acid; Lactobacillus plantarum.