Добірка наукової літератури з теми "Extraction (oenologie)"

Obtaining high-quality wines with a registered designation of origin means making the most of the specific features of the variety and those imprinted with technology and the place of harvesting. The aroma is due to the chemical compounds of terpenic nature that accumulate in the grapes (variety flavors) and the secondary aromas that are formed during the alcoholic fermentation and the aging period of the wines (Amrani, and Glories, 1995). The wine-making of the varieties is followed by the appreciation of the primary grapes. This is achieved by preferential maceration of the must by means of enzymes (Marin et al., 1998). The technology of aromatic wines has two fundamental objectives: extracting the primary aromas of grapes (terpenols) and favoring the formation of secondary fermentation aromas. In order to obtain aromatic wines with variety typology, the preferential stage is decisive. Pectolytic enzyme preparations are used in oenology to accelerate and complete the extraction and clarification processes of the must, extracting and stabilizing the color, highlighting the varietal aromatic potential of the varieties and improving the filterability and maturation of the wines.

Introduction: Mannoproteins (MP) contained in the yeast cell wall (YCW) have high biological activity and possess several techno-functional properties. They are actively used in oenology, as a colloidal stabilizer and an inhibitor of the crystallization of potassium bitartrate, agriculture, as a feed additive for animals, the food industry, as an emulsifier. We obtained MP from Saccharomyces cerevisiae yeast and evaluated antimicrobial properties against Bacillus subtilis and Escherichia coli.Methods: YCW was obtained by autolysis of 15% yeast suspension of S. cerevisiae for 24 h at the temperature of 55° C with the initial pH of 5.0 and mixing at 120 rpm. MP preparations from YCW were obtained in two ways, namely, thermal extraction at the temperature of 121° C and alkaline extraction. The precipitated protein was dried in a dehydrator and then crushed. After that, MP were tested in relation to two cultures of E. coli and B. subtilis by sowing on liquid and solid nutrient media, with the addition of MP preparation obtained by various methods and different concentrations.Results: As a result of induced autolysis, YCW was obtained with a yield of 27%. The MP yield after thermal and alkaline extraction was 12.0 and 12.9%, respectively. In relation to E. coli, alkaline MP showed the inhibitory ability of 37% at the preparation concentration of 5% (m/v). The fraction obtained by thermal means demonstrated minimal antimicrobial activity (AA). Inhibition was 4% relative to the control sample at the preparation concentration of 3% (m/v). According to the experimental data obtained with respect to B. subtilis, AA of the alkaline (3% m/v) fraction was 80%. The thermal (5% m/v) fraction did not manifest AA, on the contrary, it acted as a catalyst for colony growth.Conclusions: Mannoprotein obtained by alkaline extraction showed an inhibitory effect on the growth of B. subtilis and E. coli. The resulting preparation can be used as a feed additive to agriculture animals as an alternative to antibiotics. With proper cleaning, this preparation can be used in medicine and cosmetology. Keywords: mannoprotein, cell wall, yeast, Saccharomyces cerevisiae, antimicrobial properties

<p style="text-align: justify;"><strong>Aims</strong>: Fourier Transform-Near Infrared (FT-NIR) spectrum and instrumental texture parameters were assessed as total phenol content and extractability predictors in intact grape seeds.</p><p style="text-align: justify;"><strong>Methods and results</strong>:The study was carried out on Cabernet-Sauvignon seeds from grapes harvested at six different advanced physiological stages throughout ripening and calibrated by flotation to reduce the in-field heterogeneity inside each sample. Among the instrumental mechanical properties tested (i. e., break force, break energy, Young’s modulus of elasticity and deformation index), the seed Young’s modulus of elasticity showed an increase during the first four weeks of ripening. This parameter also showed significant correlations with phenol content and extractability, although with low R coefficients. These correlations highlighted that the springier seed tissues greatly increase phenol extractability. Nevertheless, the best prediction of seed phenol content, performed directly on intact seeds, was found using FT-NIR spectroscopy in transmittance mode. The standard error of prediction for total phenol content was less than 8 %, while that for phenol extractability was worse.</p><p style="text-align: justify;"><strong>Conclusion</strong>: On the basis of these results, the two analytical methods could be applied in oenology for the rapid monitoring of seed phenolic maturity.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The phenolic composition of grapes at the harvest time is a key factor determining their quality, and thus the quality of the finished wine. The chemical methods used for the determination of seed phenol content and extractability are generally slow because they require a preliminary extraction. Therefore, a rapid evaluation of these parameters could be highly interesting for the oenological sector.</p>

La filière viti-vinicole se doit de trouver des solutions au cours des années à venir afin de réduire son impact carbone de 20% et de proposer rapidement des alternatives au dioxyde de soufre. Ainsi, ce travail de thèse sur les champs électriques pulsés propose aux professionnels du vin une éco-innovation qui pourrait aider à répondre à ces deux problématiques. L’éco-innovation est de plus en plus considérée comme la clé de la compétitivité future dans le cadre du développement durable. Toutefois, avant d’être intégrée dans la production du vin, l’éco-innovation doit démontrer sa performance et son efficacité sans nuire à la qualité du produit et à la sécurité des consommateurs et doit être approuvée par les instances gouvernementales (OIV, UE...). A ce titre, la thèse a reçu un soutien financier conjoint du CIVB et de l’ADEME. Le principe des Champs Electriques Pulsés (CEP) est d’appliquer à un produit des impulsions électriques de quelques kilovolts durant un temps très court (quelques microsecondes) et répétées n fois. Les cellules contenues dans le produit traité (raisins, moût ou vin) voient leur potentiel transmembranaire augmenter jusqu’à l’induction de pores dans les membranes. L’irréversibilité des pores aboutit à l’extraction des composés cellulaires mais aussi à la mort des cellules. Ainsi, cette technologie, suivant le moment de son application en vinification et les paramètres opératoires, permet l’extraction des composés d’intérêts organoleptiques tels que les polyphénols mais aussi l’inactivation des microorganismes. Les CEP prennent en compte trois aspects importants pour la durabilité d’une technologie: l'environnement, l'économie et la qualité. En effet, cette technique a une série d'avantages pour le producteur de vins: elle est propre, rapide, peu chère, efficace, industrialisable et automatisable. Comparée à d’autres traitements tels que la pasteurisation, la filtration stérilisante, la thermovinification, la macération à chaud ou à froid, la cryoextraction ou encore la flash-détente, la consommation d'énergie est faible (quelques dizaines de kWh/tonne). La technologie des CEP est respectueuse de l’environnement puisqu’elle nécessite peu d’énergie et aucun intrant chimique. Elle est rapide et efficace car la durée du traitement n’est que de quelques dizaines à centaines de millisecondes. Enfin, les CEP sont une technologie non thermique et donc ne dégradent pas les molécules thermosensibles telles que les arômes. Les objectifs de ce travail de recherche ont été de comprendre l’effet des CEP sur les cellules, de déterminer les paramètres de traitement des CEP à employer pour réaliser l’extraction de composés d’intérêt des raisins et pour inactiver des microorganismes afin de stopper la fermentation alcoolique des vins liquoreux et de stabiliser microbiologiquement les vins rouges avant leur mise en bouteille en conservant la qualité du produit traité
The wine industry needs to find solutions in the coming years to reduce its carbon footprint by 20% and quickly propose alternatives to sulphur dioxide usage. This work on pulsed electric fields offers wine professionals an eco-innovation that could help to address these two issues. Eco-innovation is increasingly seen as the key to future competitiveness in the context of sustainable development. However, before being integrated in wine production, eco-innovation must demonstrate its performance and efficiency without compromising product quality and consumers safety so that it could be approved by government authorities (OIV, EU ...). As such, this thesis has received a joint financial support from the CIVB and the ADEME. The principle of Pulsed Electric Field (PEF) is to apply to a product; electrical pulses of a few kilovolts in a very short period time (a few microseconds) and then repeated n times. During treatment (grapes, grape must or wine) cells transmembrane potential increases till the induction of pores in the membranes. The irreversibility of the pores leads not only to the extraction of cellular components but also cell death. Thus, depending on the time of this technology application in winemaking and operating parameters, allows the extraction of sensory interests compounds such as polyphenols or the inactivation of microorganisms. PEF takes into account three important aspects to the sustainability of a technology: environment, economy and quality. This technique has a number of advantages for wine producers: clean, fast, inexpensive, efficient, industrializable and automated. Compared to other treatments such as pasteurization, sterile filtration, thermovinification, hot or cold maceration, cryoextraction or flash-release, its energy consumption is low (a few tens of kWh / tonne). PEF technology is environmentally friendly, as it requires little energy and no chemical inputs. It is fast and efficient because the processing time is only a few tens to hundreds of milliseconds. Finally, this technique is a non-thermal and therefore does not degrade the heat-sensitive molecules such as flavours. The objectives of this research work was to understand the effect of PEF on the cells, to determine the processing parameters during the extraction of compounds of interest grapes and to inactivate microorganisms in order to stop alcoholic fermentation of sweet wines and stabilize microbiologically red wines before bottling maintaining the quality of the processed product

Chaque année, la filière viti-vinicole génère d'importants volumes de sous-produits, dont les lies de vin, qui représentent 2 à 6 % du volume total de vin. Ces sous-produits sont principalement valorisés par distillation de l’éthanol et l’extraction de l’acide tartrique. Toutefois, l'intérêt croissant pour une valorisation plus diversifiée a conduit à de nombreuses études sur l'extraction de composés polyphénoliques, notamment à partir des lies de vin rouge. En revanche, les lies de vin blanc, bien que reconnues pour leur potentiel antioxydant dans l'élevage des vins blancs, ont reçu beaucoup moins d'attention, en raison de leur faible richesse en polyphénols et cette propriété des lies demeure donc sous-exploitée. Cette thèse étudie donc le potentiel de valorisation des lies de vin blanc à travers une approche innovante et éco-durable. Plus précisément, ce projet vise à développer et optimiser des procédés d’extraction et de fractionnement des lies de vin blanc guidés par la capacité antioxydante des extraits obtenus.Tout d’abord, l'influence de plusieurs procédés de séchage sur la préservation de l’activité antioxydante des lies a été étudiée. Pour cela, différentes matrices de lies ont été collectées et analysées afin d’évaluer la variabilité de leur composition en fonction de leur origine vinicole. Par la suite, des méthodes d'extraction durables, telles que l'extraction au CO₂ supercritique et à l'eau sous-critique, ont été comparées à des solvants conventionnels. Les extraits présentant la plus forte capacité antioxydante ont été obtenus par extraction à l'eau sous-critique. Ce procédé a ainsi été sélectionné et une étude d'optimisation, basée sur la méthodologie des surfaces de réponse, a été menée afin de déterminer les conditions opératoires optimales permettant de maximiser l'activité antioxydante des extraits.Dans un contexte de réduction des intrants œnologiques et notamment du dioxyde de soufre (SO₂), l’impact des extraits de lies non purifiés sur la prévention des phénomènes d’oxydation du vin a été ensuite étudié. Les résultats obtenus ont démontré que les extraits présentent des propriétés antioxydantes pertinentes et comparables à celles de produits commerciaux tels que les dérivés de levures. Toutefois, leur action antioxydante reste inférieure à celle du SO₂ et leur utilisation pourrait altérer les propriétés sensorielles du vin, influençant ainsi sa qualité finale. Dans le but de minimiser cet impact sensoriel, une étude de fractionnement par ultrafiltration a été réalisée. Afin d'évaluer l'impact des performances des procédés membranaires, des membranes d'ultrafiltration présentant différents seuils de coupure et soumises à divers paramètres opératoires ont été étudiées dans le but de concentrer la fraction antioxydante des extraits. Ce procédé a ainsi permis de concentrer leur capacité antioxydante d'un facteur 1,5. Par ailleurs, les résultats du fractionnement révèlent que la fraction antioxydante des extraits, corrélée au contenu en azote et en lipides des lies, est composée de molécules dont les poids moléculaires se situent entre 10 kDa et moins de 1 kDa.Le couplage de ces procédés, sans utilisation de solvants organiques, permet une extraction efficace et une concentration de composés à haute valeur ajoutée issus des lies de vin blanc. Ce travail contribue ainsi à améliorer la durabilité économique et environnementale de la gestion de ces résidus, tout en ouvrant des perspectives pour d'autres applications d'extraction au sein des distilleries
Each year, the wine industry produces significant volumes of by-products, including wine lees, which account for 2 to 6% of the total volume of wine produced. These by-products are mainly valorized through ethanol distillation and tartaric acid extraction. Over the past decade, the increasing interest in by-product valorization has led to numerous studies on the extraction of polyphenolic compounds from red wine lees. However, although white wine lees are well-recognized for their antioxidant potential during aging of white wines, they have received less attention due to their low polyphenol content, and this potential remains largely underexploited. Therefore, the objective of this study is to propose an eco-sustainable approach to valorizing white wine lees. Specifically, this project aimed to develop and optimize extraction and fractionation processes of white wine lees, guided by their antioxidant capacity.Initially, the influence of various drying processes on the preservation of the antioxidant activity of the lees was studied. To achieve this, different lees matrices were collected and analyzed to assess the variability in their composition depending on their winemaking origin. Then, sustainable extraction methods, such as supercritical CO₂ extraction and subcritical water extraction, were compared with conventional solvents. The extracts with the highest antioxidant capacity were obtained by subcritical water extraction. This process was selected and optimized using response surface methodology to determine the optimal operating conditions for maximizing the antioxidant activity of the extracts.In the context of oenological research focused on alternatives to sulfur dioxide (SO₂), the impact of the lees extracts on preventing wine oxidation was investigated. The extracts demonstrated antioxidant properties in wine, comparable to those of commercial products such as yeast derivatives. However, their antioxidant effectiveness remained lower to that of SO₂. Furthermore, their use could impact the sensory properties of the wine and its overall quality.In order to propose extracts that are more neutral in terms of sensory impact, a fractionation study using ultrafiltration was conducted. To evaluate the impact of membrane process performance, ultrafiltration membranes with different molecular weight cut-offs and with various operational conditions were studied to concentrate the antioxidant fraction of the extracts. This process allowed the antioxidant capacity to be concentrated by a factor of 1.5. Additionally, the fractionation results revealed that the antioxidant fraction of the extracts, correlated with the nitrogen and lipid content of the lees, consists of molecules with molecular weights ranging between 10-1 kDa.The combination of these processes, without the use of organic solvents, allows for the efficient extraction and concentration of high-value compounds from white wine lees. This study thus contributes to improving the economic and environmental sustainability of managing these residues, while also opening up perspectives for other extraction applications within distilleries

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2011.
Includes bibliography.
ENGLISH ABSTRACT: Grape and wine phenols consist of flavanols which is the building blocks for tannins. These building blocks are called monomers which consist of catechins, epicatechins, epigallocatechins and epicatechin-gallate. Tannin is important in wine as it contributes to bitterness, mouth feel (astringency) and maturation potential of the wine. Futhermore it has a health benefit as an antioxidant. Anthocyanins are responsible for the colour of red wine. The anthocyanins combine with tannins to form stable polymeric pigments. Due to the importance of tannins and anthocyanins in wine, it is imperitative that different winemaking techniques are used to extract as much of these components as possible and that the analysis is done quickly and accurately. The aim of this study was to evaluate different winemaking techniques and their extraction of tannins and anthocyanins into the wine. Too much tannin extraction can have a negative effect on the sensory quality of the wine. Therefore a second aim was to evaluate the mouth feel properties of a Shiraz wine. A third aim was to compare the two tannin precipitation methods in terms of time efficiency, repeatability and the ease of practice. To investigate the amount of tannin concentration extracted by different winemaking techniques, two cultivars (Cabernet Sauvignon and Shiraz) were used. These treatments included the addition of an enzyme during fermentation [E], cold maceration [CM], post maceration [PM] and the combination of cold and post maceration [CM+PM]. The grapes were harvested in two different climatic areas during the 2008 and 2009 vintages. The two climatic areas were classified according to the Winkler scale as a III (Morgenster) and a IV (Plaisir de Merle). The grapes were harvested at two different ripeness levels in order to evaluate the effect of the different winemaking processes on the extraction of tannins and anthocyanins. One harvest was before (LB) and the other after (HB) the commercial harvest. The results of this study showed significant differences in the phenolic composition of the wines. It was found that the warmer area showed higher tannin concentrations than the cooler area for both cultivars. In the 2008 Cabernet Sauvignon the CM extracted higher concentrations of tannin from the cooler area at both ripeness levels. In the warmer area, CM extracted the highest tannin concentration HB, but the CM+PM extracted the highest tannin concentration from Cabernet Sauvignon at the LB and CM at the HB of the warmer area. In 2009 the PM extracted the highest concentration of tannin at the lower ripeness level, while the E treatment extracted the highest concentration from the warmer area. In the cooler area the CM+PM extracted the highest concentration of tannin at a lower ripeness level, while there were no siginicant differences between the different treatments at the higher ripeness level. The highest anthocyanin concentration was found in the cooler area. The CM treatment was found to have no effect on anthocyanin extraction. Different methods are available to quantify the tannin concentration in wine. Two of the most popular tannin analytical methods are the bovine serum albumin (BSA) and the methyl cellulose precipitable tannin (MCP) methods. The BSA method is a very complex method which uses at least 3 times more reagents than the MCP method. The MCP method only analyzes tannins, while the BSA method analyzes tannins, monomeric pigments (MP), small polymeric pigments (SPP) and large polymeric pigments (LPP). In this study a good correlation was found between the two tannin precipitation methods (R2 – 0.88). There is controversy regarding the variability of these methods. Some scientists found that the two methods show a good correlation with HPLC, while others found that there was no such correlation between the precipitation methods and the HPLC. The MCP method had a practical advantage as it could be performed in half the time required for the BSA method. This has a significant impact in scenarios where a high sample throughput is required although it only measures total tannin. The phenolic composition and mouth feel of the wine was strongly influenced by the climatic area. In the warmer area the effect of tannin concentration on mouth feel was much less than in the cooler area. The wine made of riper grapes, was more grippy, bitter and numbing than the wines made from greener grapes. The E treatment was especially associated with a dry, grippy sensation.
AFRIKAANSE OPSOMMING: Druif en wyn fenole bestaan uit flavanole wat weer die boublokke is van tanniene. Hierdie boublokke, wat bekend staan as monomere, betsaan uit katesjiene, epikatesjiene, epigallokatesjiene an epikatesjien-gallaat. Tanniene is belangrik in wyn aangesien dit bydra tot bitterheid, mondgevoel (vrankheid) asook die verouderingspotensiaal van wyn. As antioksidante hou dit ook gesondheidsvoordele in. Antosianiene dra by tot die kleur van rooiwyn. Antosianiene kombineer met tanniene om meer stabiele polimeriese pigmente te vorm. As gevolg van die belangrikheid van tanniene en antosianiene is dit van uiterse belang dat verskillende wynmaak tegnieke gebruik word om ekstraksie in die wyn te bevoordeel en dat die analitiese metode so vinnig en akkuraat as moontlik gedoen word. Die eerste doel van hierdie studie was om die ekstraksie van tanniene en antosianiene deur middel van verskillende wynmaak tegnieke te evalueer. Te veel tanniene in die wyn kan negatiewe sensoriese kwaliteit tot gevolg het. Daarom is die tweede doel om die sensoriese kwaliteit van Shiraz wyn te evalueer. Die derde doel van hierdie studie was die twee tannien presipitasie metodes met mekaar te vergelyk in terme van die moeilikheidsgraad van die metode, tyd doeltreffendheid en herhaalbaarheid. Verskillende wynmaak tegnieke (ensiem byvoegings [E], koue maserasie [CM], verlengde dopkontak [PM] en ‘n kombinasie van koue maserasie en verlengde dopkontak [CM+PM]) is vergelyk ten opsigte van tannien en antiosianien ekstraksie. In 2008 en 2009 is twee kultivars (Cabernet Sauvignon en Shiraz) in twee verskillende klimatologiese areas gepars. Hierdie areas is geklassifiseer in die Winklerskaal as ‘n IV (Plaisir de Merle) en ‘n III (Morgenster). Om die effek van die verskillende wynmaak tegnieke op die ekstraksie van antosianiene en tanniene te vergelyk, is hierdie twee kultivars by twee verskillende rypheidsgrade geoes. Die eerste oes was net voor kommersiële oes (LB) en die tweede oes het net na kommersiële oes (HB) plaasgevind. Die 2009 Shiraz wyn is organolepties beoordeel om die effek van die verskillende wynmaak tegnieke op die wyn se mondgevoel te vergelyk. Die resultate van hierdie studie toon beduidende verskille in die fenoliese samestelling van die wyne. Dit is gevind dat die warmer area hoër tannien konsentrasies het as die koeler area. In 2008 het die CM+PM die meeste tanniene uit die Cabernet Sauvignon geëkstraheer by LB en die CM by HB in die warmer area. Die CM het in die koeler area meer tanniene geëkstraheer by beide die LB en HB rypheidsgrade. In 2009 het PM die meeste tanniene geëkstraheer by LB terwyl E die meeste tanniene geëkstraheer in die warmer area. In die koeler area het CM+PM die meeste tanniene geëkstraheer, terwyl geen van die behandelings ‘n effek gehad het by HB. Die meeste antosianien konsentrasie was in die koeler area gevind as in die warmer area. In beide 2008 (LB en HB) en 2009 (LB) het CM die meeste antosianiene geëkstraheer, terwyl geen behandeling ‘n effek gehad het by HB. Twee van die mees populêre tannien analitiese metodes is die BSA (bovine serum albumien) en die MCP (metielsellulose presipitasie) metodes. Die BSA metode is ‘n baie meer ingewikkelde metode waarvoor drie keer meer reagense gebruik word as vir die MCP metode. Maar waar die MCP net tanniene ontleed, ontleed die BSA metode tanniene, monomere (MP), klein polimeriese pigmente (SPP) en groot polimeriese pigmente (LPP). Dit help indien daar gekyk wil word na die evolusie van polimeriese pigmente. In hierdie studie is bevind dat daar ‘n redelike korrelasie (R2 – 0.88) tussen die BSA en MCP metode bestaan. Die herhaalbaarheid van die metodes het redelike kontroversie veroorsaak, waar sommige navorsers bevind het dat die BSA metode nie so herhaalbaar is soos eers bevind is nie. Die MCP metode het ’n praktiese voordeel aangesien dit in die helfde van die tyd van die BSA metode uitgevoer kan word. Dit het ‘n groot impak indien ‘n groot hoeveelheid monsters ontleed moet word. Die fenoliese samestelling en mondgevoel word sterk beïnvloed deur die klimatologiese area. In die warmer area was die effek van tannien konsentrasie op mondgevoel kleiner as in die koeler area. Die wyn van ryper druiwe het meer harder, verdowingseffek en bitter nasmaak gehad as by die wyn van groener druiwe. Die ensiem behandeling was meer geassossieerd met droë mond gevoel.