Yearly Archives: 2020

Grape solids: new advances on the understanding of their role in enological alcoholic fermentation

Residual grape solids (suspended particles) in white and rosé musts vary depending on the clarification pro-cess. These suspended solids contain lipids (more especially phytosterols) that are essential for yeast meta-bolism and viability during fermentation in anaerobic conditions. We present here recent advances on the understanding of the role of the solid particles during alcoholic fermentation […]

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Bio-protection by one strain of M. Pulcherrima: microbiological and chemical impacts in red wines

Keywords: Wine bio-protection, Metschnikowia pulcherrima, Metabolomic, Volatile and phenolic compounds  In oenology, bio-protection consists in adding bacteria, yeasts or a mixture of microorganisms on grape must before fermentation in order to reduce the use of chemical compounds such as sulphites. More particularly, non-Saccharomyces yeasts are used as a total or partial alternative to sulphites. However, scientific data […]

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Simplifying the measurement of different forms of cu in wines and strategies for efficient removal

Copper (Cu) is known to substantially impact wine stability through oxidative, reductive or colloidal phenomena. Recent work has shown that Cu exists predominantly in a sulfide-bound form, which may act as a potential source of sulfidic off-odours in wine and hence contribute to reductive flavours. The quanti-fication of different forms of copper in wine may […]

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Optimizing the use of bentonite for better control of haze formation In white and rosé wines

In winemaking, the appearance of turbidity in white and wine is a serious visual defect, which lowers significantly its commercial value. A major cause of the formation of turbidity in wine is attributed to the presence of temperature-sensitive proteins. The proteins undergo slow conformational changes, leading to aggregation and flocculation phenomena. The process can be […]

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Foamability of bentonite treated wines: impact of new acacia gum fractions obtained by ionic exchange chromatography (IEC)

Foam is a key aspect of quality of sparkling wines. Bentonite is usually added to the wine to prevent protein haze, but reducing its foamability [1]. New skills are searching to avoid this undesirable event [2]. Acacia senegal gum (Asen) is an exudate from Acacia trees, which can be used to stabilize red wine color. […]

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Grape seed powder as an alternative to bentonite for wine fining

PR proteins can cause haze in wines, and the risk is to keep the wine unsold. Generally, in winemaking bentonite solves this problem by removing proteins, but it is not a renewable resource, has poor settling, which means difficulty in filtering after use and a considerable loss of wine, it is not a specific adsorbent […]

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Use of antisense RNA technology to modulate gene expression in Œnococcus oeni

Œnococcus oeni is a wine-associated lactic acid bacterium performs the malolactic fermentation, which improves the taste and aromatic complexity of many wine. Although, wine exhibits harsh and challenging conditions (low pH, low temperature, nutrient-poor and presence of ethanol), O. oeni possesses a remarkable adaptability to those physiochemical conditions.  Mechanisms for responding to environmental changes are […]

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Nitrogen metabolism in Kluyveromyces marxianus and Saccharomyces cerevisiae: towards a better understanding of fermentation aroma production

During wine alcoholic fermentation, yeasts produce volatile aroma compounds from sugar and nitrogen metabolism. Some of the metabolic pathways leading to these compounds have been known for more than a century. Yet, the differences in compound yield and nature between species remain poorly understood. Using a two-pronged approach of isotopic filiation and transcriptome analysis, this […]

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Mathematical modeling of fermentation kinetics: a tool to better understand interactions between Torulaspora delbrueckii and Saccharomyces cerevisiae in mixed cultures

Nowadays the use of Torulaspora delbrueckii is more and more common in winemaking. However, its behavior in presence of Saccharomyces cerevisiae is not always predictable. Indeed, the interactions existing between the two yeasts are still not well characterized and can lead to a bad control during their implementation in mixed cultures. The objective of the […]

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Impact of non-Saccharomyces in malolactic fermentation of white and red winemaking

Nowadays the use of non-Saccharomyces as starters of alcoholic fermentation (AF) has increased because of the modulation of the organoleptic profile of wines. Additionally, these wines can undergo a malolactic fermentation (MLF) driven out by lactic acid bacteria, mainly Oenococcus oeni. Since MLF is usually performed after AF, MLF is highly influenced by the metabolism […]

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