Lactobacillus demonstrate thiol-independent metabolism of methylglyoxal: Implications toward browning prevention in Parmesan cheese

Author(s)

Gandhi, N. N. ^[1] ; Cobra, P. F. ^[2] ; Steele, J. L. ^[1] ; Markley, J. L. ^[2] ; Rankin, S. A. ^[1]

Affiliation

^[1] Univ Wisconsin, Dept Food Sci, Natl Magnet Resonance Facil, 1605 Linden Dr, Madison, WI 53706 - USA

^[2] Univ Wisconsin, Dept Biochem, Natl Magnet Resonance Facil, 420 Henry Mall, Madison, WI 53705 - USA

• Document type: Journal article
• Source: JOURNAL OF DAIRY SCIENCE; v. 101, n. 2, p. 968-978, FEB 2018.
• Web of Science Citations: 1

Abstract

Endogenous production of alpha-dicarbonyls by lactic acid bacteria can influence the quality and consistency of fermented foods and beverages. Methylglyoxal (MG) in Parmesan cheese can contribute toward undesired browning during low temperature ripening and storage conditions, leading to the economic depreciation of affected cheeses. We demonstrate the effects of exogenously added MG on browning and volatile formation using a Parmesan cheese extract (PCE). To determine the influence of Lactobacillus on alpha-dicarbonyls, strains were screened for their ability to modulate concentrations of MG, glyoxal, and diacetyl in PCE. It was found that a major metabolic pathway of MG in Lactobacillus is a thiol-independent reduction, whereby MG is partially or fully reduced to acetol and 1,2-propanediol, respectively. The majority of lactobacilli grown in PCE accumulated the intermediate acetol, whereas Lactobacillus brevis 367 formed exclusively 1,2-propanediol and Lactobacillus fermentum 14931 formed both metabolites. In addition, we determined the inherent tolerance to bacteriostatic concentrations of MG among lactobacilli grown in rich media. It was found that L. brevis 367 reduces MG exclusively to 1,2-propanediol, which correlates to both its ability to significantly decrease MG concentrations in PCE, as well as its significantly higher tolerance to MG, in comparison to other lactobacilli screened. These findings have broader implications toward lactobacilli as a viable solution for reducing MG-mediated browning of Parmesan cheese. (AU)

• FAPESP's process: 12/12847-5 - Analysis of leishmaniasis metabolic profile by NMR
• Grantee: Paulo Falco Cobra
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/02534-8 - Application of NMR-Based metabolomics to biomedical problems
• Grantee: Paulo Falco Cobra
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate