Redox Potential: Monitoring and Role in Development of Aroma Compounds, Rheological Properties and Survival of Oxygen Sensitive Strains During the Manufacture of Fermented Dairy Products

Martin, Florence; Ebel, Bruno; Rojas, Christine; Gervais, Patrick; Cayot, Nathalie; Cachon, Rémy

doi:10.5772/51137

Cited by 7 publications

(3 citation statements)

References 54 publications

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“…The different redox-active molecules that were tested have different structures but sometimes similar redox potentials such as ascorbic acid, trolox, or epinephrine. − …”

Section: Resultsmentioning

confidence: 99%

Impact of Redox-Active Molecules on the Fluorescence of Polymer-Wrapped Carbon Nanotubes

2016

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The near-infrared (nIR) fluorescence of polymer-wrapped single-walled carbon nanotubes (SWCNTs) is very sensitive to the local chemical environment. It has been shown that certain small reducing molecules can increase the fluorescence of SWCNTs. However, so far the role of the polymer around the SWCNT as well as the mechanism is not understood. Here, we investigated how reducing and oxidizing small molecules affect the nIR fluorescence of polymer-wrapped SWCNTs. Our results show that the polymer plays an essential role. Reducing molecules such as ascorbic acid, epinephrine, and trolox increased the nIR fluorescence up to 250% but only if SWCNTs were suspended in negatively charged polymers such as DNA or poly(acrylic acid) (PAA). In comparison, phospholipid−poly(ethylene glycol) wrapped SWCNTs did not respond at all while positively charged polyallylamine-wrapped SWCNTs were quenched. Oxidized equivalents such as dehydroascorbic acid did not show a clear tendency to quench or increase fluorescence. Only riboflavin with an intermediate oxidation potential and light absorption in the visible range quenched all polymerwrapped SWCNTs. In general, polymer-wrapped SWCNTs that responded to reducing molecules (e.g., +141%, ascorbic acid) also responded to oxidizing molecules (e.g., −81%, riboflavin). Nevertheless, several reducing molecules showed only a small fluorescence increase (NADH, +21%) or even a decrease (glutathione, −14%), which highlights that the redox potential alone cannot explain fluorescence changes. Furthermore, we show that neither changes of absorption cross sections, scavenging of reactive oxygen species (ROS), nor free surface areas on SWCNTs explain the observed patterns. However, results are in agreement either with a redox reaction of the polymer or conformational changes of the polymer that change fluorescence decay routes. In summary, we show that the polymer around SWCNTs governs how redox-active molecules change nIR fluorescence (quantum yield) of SWCNTs. Molecules with a low redox potential (<−0.4 V) are more likely to increase SWCNT fluorescence, but a low redox-potential alone is not sufficient.

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“…The different redox-active molecules that were tested have different structures but sometimes similar redox potentials such as ascorbic acid, trolox, or epinephrine. − …”

Section: Resultsmentioning

confidence: 99%

Impact of Redox-Active Molecules on the Fluorescence of Polymer-Wrapped Carbon Nanotubes

2016

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“…Kieronczyk et al (2006) reported a higher quantity of benzaldehyde when LAB were grown in vitro at positive redox potential. A study by Martin et al (2013) analysed the volatile compounds produced by yogurts under reducing or oxidising conditions, made by the usage of gasses. The authors found that yogurts made under positive redox potential had higher quantities of acetaldehyde and diacetyl and lower level of DMS.…”

Section: Resultsmentioning

confidence: 99%

Control of oxidation-reduction potential during Cheddar cheese ripening and its effect on the production of volatile flavour compounds

Caldeo

Hannon

Hickey

et al. 2016

Journal of Dairy Research

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In cheese, a negative oxidation-reduction (redox) potential is required for the stability of aroma, especially that associated with volatile sulphur compounds. To control the redox potential during ripening, redox agents were added to the salted curd of Cheddar cheese before pressing. The control cheese contained only salt, while different oxidising or reducing agents were added with the NaCl to the experimental cheeses. KIO3 (at 0·05, 0·1 and 1%, w/w) was used as the oxidising agent while cysteine (at 2%, w/w) and Na2S2O4 (at 0·05 and 0·1%, w/w) were used as reducing agents. During ripening the redox potential of the cheeses made with the reducing agents did not differ significantly from the control cheese (E h ≈ -120 mV) while the cheeses made with 0·1 and 0·05% KIO3 had a significantly higher and positive redox potential in the first month of ripening. Cheese made with 1% KIO3 had positive values of redox potential throughout ripening but no starter lactic acid bacteria survived in this cheese; however, numbers of starter organisms in all other cheeses were similar. Principal component analysis (PCA) of the volatile compounds clearly separated the cheeses made with the reducing agents from cheeses made with the oxidising agents at 2 month of ripening. Cheeses with reducing agents were characterized by the presence of sulphur compounds whereas cheeses made with KIO3 were characterized mainly by aldehydes. At 6 month of ripening, separation by PCA was less evident. These findings support the hypothesis that redox potential could be controlled during ripening and that this parameter has an influence on the development of cheese flavour.

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“…5a-d effect on indigo pure yield. Biological energy is stored and released frequently by means of redox reactions (Martin et al 2013) which help to understand the metabolic flux of the system. Figure 5a-d represents the experimental setup, where the vector value of spontaneous reaction lies on the Y axis (negative) of the graph, indicating the consumption of oxygen in fermented liquor with high anaerobic metabolic activity.…”

Section: Effect Of Redox Potential On Pure Indigo Yieldmentioning

confidence: 99%

Effect of different physico-chemical parameters for natural indigo production during fermentation of Indigofera plant biomass

2017

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Natural indigo production from plant biomass requires fermentation of biomass, oxidation of fermented broth, settling of oxidized product (indigo), filtration and recovery. In this study, we have investigated roles of physico-chemical parameters during fermentation with respect to product yield. The study showed that water-to-biomass ratio (1:10), fermentation duration (0, 6, 12, 18, 24 h), pH (6-7.5), dissolved oxygen concentration; DO (0.5-3 mg ml), oxidation reduction potential ORP (+50 to -300 mV) and temperature (25-40 °C) during fermentation, oxidation and dye recovery from the broth are directly or indirectly related to indigo yield. Biomass fermentation for 12 h at 40 °C incubation temperature yields the highest biogenic indigo (2.84 mg g) out of the different experimental conditions.

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Redox Potential: Monitoring and Role in Development of Aroma Compounds, Rheological Properties and Survival of Oxygen Sensitive Strains During the Manufacture of Fermented Dairy Products

Cited by 7 publications

References 54 publications

Impact of Redox-Active Molecules on the Fluorescence of Polymer-Wrapped Carbon Nanotubes

Impact of Redox-Active Molecules on the Fluorescence of Polymer-Wrapped Carbon Nanotubes

Control of oxidation-reduction potential during Cheddar cheese ripening and its effect on the production of volatile flavour compounds

Effect of different physico-chemical parameters for natural indigo production during fermentation of Indigofera plant biomass

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