Production of branched-chain aroma compounds byPropionibacterium freudenreichii: links with the biosynthesis of membrane fatty acids

Abstract

Aims: Short branched‐chain fatty acids (BCFAs) are cheese flavour compounds, which result from the conversion of branched‐chain amino acids (BCAAs). In Swiss cheese, the production of short BCFAs is mainly performed by Propionibacterium freudenreichii and is strain dependent. Our aim was to investigate the possible links between the biosynthesis of short BCFAs and membrane BCFAs in P. freudenreichii. Methods and Results: Short and membrane BCFAs were analysed by gas chromatography‐mass spectrometry. Two strains differing in their capacities to release short BCFAs were selected. Tri‐deuterated‐labelled leucine was used in both strains as a precursor of short extracellular iso‐BCFAs and of membrane iso‐BCFAs. The proportions of anteiso : iso BCFAs synthesized varied as function of the BCAAs provided in the growth medium, from 72 : 28 to 100 : 0, with leucine and valine, and with isoleucine as sole BC precursors, respectively. The branching pattern of short BCFAs exactly matched that of membrane BCFAs, whatever the exogenous BCAAs provided. Conclusions: The biosynthesis of short BCFAs is closely related to that of membrane BCFAs in P. freudenreichii. Significance and Impact of the Study: The biosynthesis of short BCFAs in P. freudenreichii depends more on the strain than on the presence of exogenous BC precursors.

Contribution of volatiles to the antifungal effect of Lactobacillus paracasei in defined medium and yogurt

“…A chemically defined interaction medium (CDIM) used for growth of L. paracasei DGCC 2132 and antifungal activity tests was prepared based on defined media previously reported for growth of fungi (Andersen et al, 2003;Bockelmann et al, 1999;Emeh and Marth, 1976;Hobot and Jennings, 1981;Meyers and Knight, 1958), LAB (Morishita et al, 1974;Møretrø et al, 1998;Saguir and de Nadra, 2007;Savijoki et al, 2006) and other potential antifungal species such as propionic acid bacteria (Dherbécourt et al, 2008;Glatz and Anderson, 1988).…”

Dairy Propionibacteria: Less Conventional Probiotics to Improve the Human and Animal Health

“…These important flavour compounds are almost entirely produced in cheese by propionibacteria that synthesize them in closely related manner to that of cell membrane fatty acids [62].…”

Strain-to-strain differences within lactic and propionic acid bacteria species strongly impact the properties of cheese–A review

“…However, the amounts of BC volatile fatty acids produced are highly strain-dependent. For example, the concentrations of BC volatile fatty acids ranged from 6 to over 50 mg.mL −1 in the cultures of 40 strains of P. freudenreichii grown in cheese-like conditions (Dherbécourt et al 2008). They ranged from 19 to 114 mg.kg −1 at the end of ripening in eight experimental Swiss cheese manufactured using a single strain culture of P. freudenreichii (Thierry et al 2004a).…”