Modelling and validation of the antifungal activity of DL-3-phenyllactic acid and acetic acid on bread spoilage moulds

Els Debonne; An Vermeulen; Naomi Bouboutiefski; Tony Ruyssen; Filip Van Bockstaele; Mia Eeckhout; Frank Devlieghere

doi:10.1016/j.fm.2019.103407

Modelling and validation of the antifungal activity of DL-3-phenyllactic acid and acetic acid on bread spoilage moulds

Food Microbiol. 2020 Jun:88:103407. doi: 10.1016/j.fm.2019.103407. Epub 2019 Dec 19.

Authors

Els Debonne¹, An Vermeulen², Naomi Bouboutiefski³, Tony Ruyssen⁴, Filip Van Bockstaele⁵, Mia Eeckhout⁶, Frank Devlieghere⁷

Affiliations

¹ Research Unit of Cereal and Feed Technology, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium; Laboratory of Applied Mycology (MYCOLAB), Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium. Electronic address: els.debonne@ugent.be.
² Research Unit of Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
³ Research Unit of Cereal and Feed Technology, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium.
⁴ Laboratory of Applied Mycology (MYCOLAB), Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium.
⁵ Laboratory of Food Technology and Engineering, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
⁶ Research Unit of Cereal and Feed Technology, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium; Laboratory of Applied Mycology (MYCOLAB), Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium.
⁷ Laboratory of Applied Mycology (MYCOLAB), Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium; Research Unit of Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.

PMID: 31997763
DOI: 10.1016/j.fm.2019.103407

Abstract

Most interesting antifungal compounds from sourdough fermentation are acetic acid (AA) and DL-3-phenyllactic acid (PLA). Although the role of pH on the activity of organic acids has been established long time ago, no information is available on the importance of undissociated acid (HA) expressed on the aqueous phase of bread (C_HA, mmole/L). Mostly, concentrations (mmole/kg dough or bread, C_TOT) and pH are given side by side. The aim of this study was to show the importance of C_HA for adequate comparison of in-vitro growth data with bread shelf-life. Growth of Penicillium paneum and Aspergillus niger was recorded using a micro-dilution assay with optical density measurements. Parameters such as a_w (0.94-0.98), pH (4.6-6.0), temperature (10-30 °C), time (0-8 days) and C_TOT (0-300 mM) were varied. Growth/no-growth models were developed and shelf-life tests of par-baked breads of 45 days at 20 °C were conducted. The modelled inhibitory concentrations of undissociated acid were comparable with the shelf-life test of bread: (PLA) 50 versus 39-84 mmol/L; (AA) 110 versus 110-169 mmol/L. This study showed the applicability of G/NG models for bread shelf-life prediction and highlighted the importance of CHA. Moreover, it was found that naturally present PLA in sourdough bread is insufficient to increase bread shelf-life.

Keywords: Acetic acid; Bread spoilage; Modelling; Phenyllactic acid; Preservation.

Publication types

Validation Study

MeSH terms

Acetic Acid / pharmacology*
Antifungal Agents / pharmacology*
Aspergillus niger / drug effects
Aspergillus niger / growth & development
Bread / microbiology*
Culture Media / chemistry
Food Microbiology / methods
Food Preservation / methods
Food Preservatives / pharmacology*
Food Storage
Fungi / drug effects*
Fungi / growth & development*
Hydrogen-Ion Concentration
Lactates / pharmacology*
Microbial Sensitivity Tests
Models, Biological
Penicillium / drug effects
Penicillium / growth & development

Substances

Antifungal Agents
Culture Media
Food Preservatives
Lactates
3-phenyllactic acid
Acetic Acid