Monitoring Hydroxycinnamic Acid Decarboxylation by Lactic Acid Bacteria Using High-Throughput UV-Vis Spectroscopy

Gonzalo Miyagusuku-Cruzado,Rafael Jiménez-Flores,Diana Rocha-Mendoza,Israel García-Cano,M Monica Giusti

doi:10.3390/molecules25143142

Abstract

Hydroxycinnamic acid (HCA) decarboxylation by lactic acid bacteria (LAB) results in the production of 4-vinylplenols with great impact on the sensorial characteristics of foods. The determination of LAB decarboxylating capabilities is key for optimal strain selection for food production. The activity of LAB strains from the Ohio State University—Parker Endowed Chair (OSU-PECh) collection potentially capable of synthesizing phenolic acid decarboxylase was evaluated after incubation with HCAs for 36 h at 32 °C. A high-throughput method for monitoring HCAs decarboxylation was developed based on hypsochromic shifts at pH 1.0. Out of 22 strains evaluated, only Enterococcus mundtii, Lactobacillus plantarum and Pediococcus pentosaceus were capable of decarboxylating all p-coumaric, caffeic and ferulic acids. Other strains only decarboxylated p-coumaric and caffeic acid (6), only p-coumaric acid (2) or only caffeic acid (1), while 10 strains did not decarboxylate any HCA. p-Coumaric acid had the highest conversion efficiency, followed by caffeic acid and lastly ferulic acid. Results were confirmed by HPLC-DAD-ESI-MS analyses, showing the conversion of HCAs into their 4-vinylphenol derivatives. This work can help improve the sensory characteristics of HCA-rich foods where fermentation with LAB was used during processing.

Highlights

Hydroxycinnamic acids (HCAs) are secondary metabolites in plants and fungi characterized by a C6–C3 structure [1]
The first goal was to monitor the decarboxylation of HCAs using a fast, high-throughput method based on UV-Vis light absorption changes
Results were consistent with the formation of 4VPs, decarboxylated products from p-coumaric acid (pCA), caffeic acid (CA) and ferulic acid (FA), while no decarboxylation was observed for sinapicsubsequent acid (SA)

Summary

Introduction

Hydroxycinnamic acids (HCAs) are secondary metabolites in plants and fungi characterized by a C6–C3 structure [1]. It has been reported that not all bacterial [6] or all yeast strains [7] are capable of decarboxylating HCAs that lead to the formation of 4-vinylphenols (4VPs) or their reduced form, 4-ethylphenols. In fermented products such as wine, HCA degradation by yeast results in the formation of 4VPs; which are responsible for imparting distinct phenolic off-flavors in the final product [7].

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