Automatization of membrane contactors and applications for the management of dissolved gases in wines

Over the last decade, several distinct research groups tested possible uses of membrane contactors for the wine industry, notably for the management of dissolved gases in wines, adjustment of the O2 concentration while reducing the O2 concentration at the same time. Other experiments were done with partial alcohol reduction and addition of N2 to wines. The contactor’s heart is its Liqui-Cel™ membrane where the two separate circuits meet. The membrane’s hydrophobic characteristics allows a liquid to get in contact with a gas, without dispersing into it. The directions that these gases take through the membrane depend on their partial pressure differences within the two circuits. However, other factors need to be considered to determine exact exchange rates for each target gas. The present article describes the new membrane contactor prototype that was co-developed by the University of applied Sciences and Arts, Viticulture and Enology at Changins, Switzerland, and the School of Engineering and Architecture at Fribourg, Switzerland. The prototype was designed for small scale operations. Flow rates, temperatures and internal pressures can be instantly measured and graphically visualized. Also, O2 concentrations are measured inside the liquid. CO2 concentrations in the liquid can be measured with a device that is connected to the liquid circuit through a bypass after the membranes.Während mehr als zehn Jahren testeten verschiedene Forschungsgruppen Einsatzmöglichkeiten von Membran-Kontaktoren für die Weinindustrie. Im Besonderen wurde die genaue Einstellung von gelösten Gasen im Wein untersucht, z. B. die Anpassung der CO2-Konzentration und gleichzeitige Reduzierung der O2-Konzentration. Teilweise Alkoholreduktion und Zugabe von N2 zum Wein sind weitere Möglichkeiten. Das Herzstück des Kontaktors ist seine Liqui-Cel™-Membran, wo sich zwei getrennte Kreisläufe treffen. Die wasserabstossenden Eigenschaften der Membran ermöglichen es einer Flüssigkeit, mit einem Gas in Kontakt zu treten, ohne sich darin zu verteilen. Die Richtung, die diese Gase durch die Membran nehmen, hängt von ihren unterschiedlichen Partialdrücken innerhalb der beiden Kreisläufe ab. Es müssen jedoch noch andere Faktoren berücksichtigt werden, um den genauen Austausch für jedes Gas zu ermitteln. Dieser Artikel beschreibt den neuen Prototyp eines Membran-Kontaktors, der von den Fachhochschulen für Weinbau und Önologie in Changins, Schweiz, und für Technik und Architektur in Freiburg, Schweiz, entwickelt wurde. Der Prototyp ist für die Anwendung mit kleinen Mengen vorgesehen. Fliessgeschwindigkeiten, Temperaturen und interner Druck können inline gemessen und grafisch dargestellt werden. Auch die O2-Konzentration kann im Flüssigkeitskreislauf gemessen werden. Die Konzentration von CO2 in der Flüssigkeit kann mit einem Gerät, welches nach den Membranen über einen Bypass an den Flüssigkeitskreislauf angeschlossen ist gemessen werden

Etude des protéines du vin rouge (Mécanismes d'action d'enzymes de macération sur le raisin rouge)

L étude des interactions physico-chimiques entre tanins et protéines a permis de mettre au point une technique novatrice d isolement, de purification et d analyse des protéines du vin rouge. Nous avons démontré que des vins riches en tanins contenaient des protéines et que certaines d entre elles étaient N-glycosylées. Nous proposons également une méthode d identification de ces protéines par " digestion tryptique dans le gel " et analyse des peptides d hydrolyse par spectrométrie de masse. Quantitativement, cette méthode et l utilisation d un étalon interne (BSA) permettent d estimer, avec une bonne précision (4 à 10%), la concentration individuelle et globale (20 mg/L) des protéines présentes dans le vin. Ces travaux constituent une étape capitale dans la compréhension des interactions colloïdales impliquées entre les différents constituants du vin rouge. Indépendamment, les mécanismes d action et le rôle des enzymes de macération sur le raisin et le vin rouge sont étudiés. Des observations en microscopie optique et électronique montrent que les enzymes agissent de l intérieur vers l extérieur de la baie et que cette action dépend de la dose ajoutée. Les enzymes ne détruisent pas complètement les parois des cellules de la pellicule. Elles génèrent une diminution de densité au niveau de la lamelle moyenne et forment de multiples perforations dans la paroi qui sont autant de passages permettant la diffusion sélective des tanins de la pellicule dans le vin. Les enzymes de macération permettent d obtenir des vins plus concentrés en composés pelliculaires, avec des tanins peu réactifs, très polymérisés et fortement combinés aux anthocyanes. Les enzymes de macération n agissent que sur la pellicule et ne facilitent pas l extraction des tanins de pépins. Ces différents résultats conduisent à une meilleure maîtrise et une utilisation raisonnée des enzymes de macération.BORDEAUX1-BU Sciences-Talence (335222101) / SudocBORDEAUX2-BU Santé (330632101) / SudocVILLENAVE D'ORNON-Bib. ISVV (335502201) / SudocSudocFranceF

A new method of protein extraction from red wines

Aim: Wine is a very complex medium and is often evaluated according to its main components like alcohol, sugar, tannins, and acid levels. Proteins are rarely considered in this evaluation because their concentrations are only a few mg/L of wine. However, in an enological context, proteins appear to be more and more important, in particular for the stability of wines with protein haze problems. The study of proteins is less obvious in red wines than in white wines because the proteins are strongly tied to tannins, which makes their extraction and analysis even more difficult. Methods and results: This article describes a technique for the separation of proteins from tannins thanks to a methanol/chloroform emulsion in an acid solution. The protein extract, obtained after 4 hours, was later analyzed by SDS-Page and the protein profile of the wine established. Experiments showed that the protein profiles remained the same during the different stages of the winemaking process, whereas the overall amount of proteins decreased. Characteristic protein profiles of different grape varieties were established, and it was also possible to visualize the presence of exogenous proteins from fining agents like albumin and casein. Conclusion: This procedure allowed the extraction of proteins from 8 red wine samples within 4 hours. It also made it possible to analyze the extracted proteins by SDS-Page without tannin interference within 2 hours. Significance and impact of the study: This method shows in a very promising manner how proteins might be extracted from red wines after being separated from their tannins. The extracted proteins are then available for analysis using even more advanced techniques such as ESI-QTof or ELISA

Quantification of the production of hydrogen peroxide H2O2 during accelerated wine oxidation

Understanding how wines react towards oxidation is of primary importance. Here, a novel approach was developed based on the quantitative determination of the key intermediate H2O2 produced during accelerated oxidation by ambient oxygen. The assay makes use of the conversion of the non-fluorescent Amplex Red substrate into a fluorescent product in presence of H2O2. The total production of H2O2 during 30 min was quantified with low within-day and between-day variabilities. Polymerized pigments, but not total polyphenols, played a major role in the determination of H2O2 levels, which were lower in white wines than red wines. H2O2 amounts also increased with temperature and the addition of metal ions, but did not depend on the concentration of many other wine constituents such as SO2. H2O2 levels did not correlate with anti-oxidant properties. We believe that this novel methodology might be generically used to decipher the oxidation mechanisms in wines and food products

Influence of surface chemical modification of cellulose nanowhiskers on mechanical and barrier properties of bionanocomposites based poly(lactide)

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Amber ale beer enriched with goji berries ::the effect on bioactive compound content and sensorial properties

Goji berries, traditionally used in Chinese medicine, are nowadays gaining popularity in the Western world. Efforts are made to enlarge the offer of goji containing foods. In this study, goji berries were added to ale type beer at different stages of the production process in order to develop a beverage with desirable sensory characteristic and high antioxidant capacity. The obtained beers differed significantly in terms of appearance, taste and antioxidant activity. Consumers preferred beers to which goji berries were added at the beginning of the brewing process. These beers were also characterized by lower turbidity, high color intensity, caramel- and coffee-like taste, high antioxidant activity and high content of bioactives such as rutin and 2-O-β-d-glucopyranosyl-l-ascorbic acid. To conclude, an addition of goji berries to traditional brewing process creates a perspective to enlarge the range of goji containing foods

A new chemical tool for absinthe producers, quantification of α/β-thujone and the bitter components in artemisia absinthium

The concentrations of α/β-thujone and the bitter components of Artemisia absinthium were quantified from alcoholic wormwood extracts during four phenological stages of their harvest period. A solid-phase micro-extraction method coupled to gas chromatography–mass spectrometry was used to determine the concentration of the two isomeric forms of thujone. In parallel, the combination of ultra-high pressure liquid chromatography and high resolution mass spectrometry allowed to quantify the compounds absinthin, artemisetin and dihydro-epi-deoxyarteannuin B. This present study aimed at helping absinthe producers to determine the best harvesting period

Influence of chemical surface modification of cellulose nanowhiskers on thermal, mechanical, and barrier properties of poly(lactide) based

International audienceIn the aim of producing fully organic bionanocomposite based on poly(lactide) (PLA), cellulose nanowhiskers (CNW) were grafted by n-octadecyl-isocyanate (CNW-ICN) applying an in situ surface grafting method. The compatibilizing effect of the long aliphatic grafted chain was investigated by thermal, mechanical and permeability analysis of solvent cast nanocomposite films. The grafted CNW-ICN could be successfully dispersed in the polymer matrix. The gained compatibility brought about a nucleating effect, decreasing the half time of isothermal crystallization from 25 min for the neat PLA to 8.4 min for the nanocomposite including 2.5 wt% CNW-ICN, e.g., tensile strength was improved by 10 MPa for the same 2.5 wt% CNW-ICN/PLA composite. Mechanical reinforcement was also effective in the rubbery state of PLA and increased the tensile modulus of the rubbery plateau providing thereby thermal resistance to the polymer. Oxygen barrier properties did not change significantly upon the inclusion of CNW-ICN, even when the quantity of CNW-ICN was increased to 15 wt%. More interestingly, the water vapour permeability of the CNW-ICN nanocomposite was always lower than the one of ungrafted CNW composites, which led to the conclusion that the hydrophobic surface graft and improved compatibility could counteract the effect of inclusion of hydrophilic structures in the matrix on water vapour transport. In conclusion, the surface grafting of CNW with isocyanates might be an easy and versatile tool for designing fully organic bionanocomposites with tailored properties

Des toitures-jardins pour une meilleure durabilit\ue9 des enveloppes des b\ue2timents

Les concepteurs nord-am\ue9ricains sont de plus en plus nombreux \ue0 consid\ue9rer les toitures-jardins comme une option de conception durable. Le pr\ue9sent num\ue9ro r\ue9sume une \ue9tude de terrain sur la performance thermique de cette technologie et sa capacit\ue9 \ue0 retenir les eaux pluviales.There is increasing interest in the garden roof system as a sustainable building design option in North America today. This Update reports the results of a field study to evaluate the thermal performance of this technology, as well as its potential to retain storm water runoff.Also available in English: Using Garden Roof Systems to Achieve Sustainable Building EnvelopesPeer reviewed: NoNRC publication: Ye

A new chemical tool for absinthe producers, quantification of α/β-thujone and the bitter components in artemisia absinthium

The concentrations of α/β-thujone and the bitter components of Artemisia absinthium were quantified from alcoholic wormwood extracts during four phenological stages of their harvest period. A solid-phase micro-extraction method coupled to gas chromatography–mass spectrometry was used to determine the concentration of the two isomeric forms of thujone. In parallel, the combination of ultra-high pressure liquid chromatography and high resolution mass spectrometry allowed to quantify the compounds absinthin, artemisetin and dihydro-epi-deoxyarteannuin B. This present study aimed at helping absinthe producers to determine the best harvesting period