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- Production of volatile phenols by Lactobacillus plantarum in wine conditionsPublication . Fras, Pauline; Campos, Francisco; Hogg, Tim; Couto, José AntónioSome lactic acid bacteria produce volatile phenols in culture medium but this activity has not been extensively studied in wine conditions. Red and white wines were mixed with MRS medium at different ratios to study the influence of wine on the metabolism of p-coumaric and ferulic acids by Lactobacillus plantarum. In MRS broth supplemented with these precursors at 10 mg l-1, only 4-ethylphenol was produced (1 mg l-1) while, in the presence of wine, 4-vinylphenol was also obtained. Both volatile phenols are produced in nearly equal amounts (1 mg l-1) or almost only 4-vinylphenol depending on the MRS:wine ratio. Thus, wine favours the accumulation of 4-vinylphenol. Ferulic acid was not or was weakly metabolized in the conditions studied.
- Development of a flow method for monitoring cell membrane damage: application to the study of phosphate release from wine lactic acid bacteriaPublication . Torres, André F.; Mesquita, Paulo A. R.; Tóth, Ildikó V.; Campos, Francisco M.; Couto, José A.; Hogg, Tim; Rangel, António O. S. S.
- Influence of phenolic compounds on glucose and organic acids metabolism of wine lactic acid bacteriaPublication . Bilé, Teresa; Sá, Filipa; Campos, Francisco M.; Figueiredo, Ana R.; Couto, José A.; Hogg, Tim
- Effect of phenolic acids on glucose and malic acid metabolism of Lactobacillus hilgardiiPublication . Campos, F. M.; Couto, J. A.; Hogg, T. A.
- Production of volatile phenols by wine PediococciPublication . Couto, José A.; Campos, Francisco M.; Figueiredo, Ana R.; Hogg, Tim
- Cell membrane damage induced by phenolic acids on wine lactic acid bacteriaPublication . Campos, F. M.; Couto, J. A.; Figueiredo, A. R.; Tóth, I. V.; Rangel, António O. S. S.; Hogg, T. A.
- Determinação potenciométrica de efluxo de potássio em bactérias lácticas do vinho sujeitas a stress químicoPublication . Campos, F. M.; Couto, J. A.; Hogg, T. A.; Rangel, António O. S. S.; Tóth, I. V.
- Cell membrane damage induced by phenolic acids on wine lactic acid bacteriaPublication . Campos, Francisco M.; Couto, José A.; Figueiredo, Ana R.; Tóth, Ildikó V.; Rangel, António O. S. S.; Hogg, Tim
- Development of a flow injection method for monitoring cell membrane damage of wine lactic acid bacteriaPublication . Torres, André F.; Mesquita, Paulo A. R.; Campos, Francisco M.; Couto, José A.; Tóth, Ildikó V.; Rangel, António O. S. S.; Hogg, TimA flow injection analysis (FIA) system was developed for the determination of phosphate efflux from wine lactic acid bacteria (Oenococus oeni and Lactobacillus hilgardii) as an indication of cell membrane damage. The system allowed the direct injection of the cell suspension, avoiding the filtration step, with minimumsample treatment andminimized reagent consumption. The developed system is characterized by a linear concentration zone between 3.2310 5 and 4.84104 mol L1 PO4 3 and repeatability better than 2.9%. Bacterial suspensions were exposed to a chemical stress with phenolic acids and injected in the FIAsystem at regular intervals. The extracellular concentration of phosphate was measured spectrophotometrically. The experimental results obtained indicate that hydroxycinnamic acids (p-coumaric, ferulic and caffeic) induced faster phosphate leakage rates than hydroxybenzoic acids (vanillic and p-hydroxybenzoic) in both strains tested, which could be related to their higher lipophilic character.
- The influence of wine phenolic acids on the production of volatile phenols by lactic acid bacteriaPublication . Silva, Isa; Campos, Francisco M.; Hogg, Tim; Couto, José A.