Academic literature on the topic 'Oenological properties'

Jerez (Sherry) is a well-known wine-producing region located in southern Spain, where world-renowned oenological products such as wines, vinegars, and brandies are produced. There are several factors that provide characteristic physical, chemical, and sensory properties to the oenological products obtained in this Sherry region: the climate in the area with hot summers, mild winters, and with limited rainfall; the raw material used consisting on Palomino Fino, Moscatel, and Pedro Ximénez white grape varieties; the special vinification with fortified wines; and aging techniques such as a dynamic system of biological or oxidative aging. These special organoleptic characteristics are responsible for, among others, the aromatic profile of the wines, vinegars and brandies from the area, which explains why this is a subject that has been extensively researched over the years. This bibliographic review aims to compile the different scientific contributions that have been found to date, in relation with the aroma of the oenological products from the Sherry area (dry wines, sweet wines, vinegars, and brandies). We have mainly focused on the different analytical methodologies used and on the main analytes of interest.

Winemaking depends on several elaborate biochemical processes that see as protagonist either yeasts or lactic acid bacteria (LAB) of oenological interest. In particular, LAB have a fundamental role in determining the quality chemical and aromatic properties of wine. They are essential not only for malic acid conversion, but also for producing several desired by-products due to their important enzymatic activities that can release volatile aromatic compounds during malolactic fermentation (e.g., esters, carbonyl compounds, thiols, monoterpenes). In addition, LAB in oenology can act as bioprotectors and reduce the content of undesired compounds. On the other hand, LAB can affect wine consumers’ health, as they can produce harmful compounds such as biogenic amines and ethyl carbamate under certain conditions during fermentation. Several of these positive and negative properties are species- and strain-dependent characteristics. This review focuses on these aspects, summarising the current state of knowledge on LAB’s oenological diversity, and highlighting their influence on the final product’s quality and safety. All our reported information is of high interest in searching new candidate strains to design starter cultures, microbial resources for traditional/typical products, and green solutions in winemaking. Due to the continuous interest in LAB as oenological bioresources, we also underline the importance of inoculation timing. The considerable variability among LAB species/strains associated with spontaneous consortia and the continuous advances in the characterisation of new species/strains of interest for applications in the wine sector suggest that the exploitation of biodiversity belonging to this heterogeneous group of bacteria is still rising.

The characterization of autochthonousSaccharomyces cerevisiaestrains is an important step towards the conservation and employment of microbial biodiversity. The utilization of selected autochthonous yeast strains would be a powerful tool to enhance the organoleptic and sensory properties of typical regional wines. In fact, indigenous yeasts are better tailored to a particular must and because of this they are able to praise the peculiarities of the derived wine. The present study described the biodiversity of indigenousS. cerevisiaestrains isolated from natural must fermentations of an ancient and recently rediscovered Apulian grape cultivar, denoted as “Susumaniello.” The yeast strains denoted by the best oenological and technological features were identified and their fermentative performances were tested by either laboratory assay. Five yeast strains showed that they could be excellent candidates for the production of industrial starter cultures, since they dominated the fermentation process and produced wines characterized by peculiar oenological and organoleptic features.

The present study aimed to investigate the oenological changes induced by non-Saccharomyces yeasts in three red grape varieties from the Rioja Qualified Designation of Origin. Pilot plants fermentation of three different varieties, were conducted following early inoculations with Metschnikowia pulcherrima and with mixed inoculum of Lachancea thermotolerans-Torulaspora delbrueckii from La Rioja and compared to a wine inoculated with Saccharomyces cerevisiae. The microbiological and physicochemical characteristics of vinifications were analysed. Results showed that most of the variations due to inoculation strategies were observed in Tempranillo just after the alcoholic fermentation, probably because of the better adaptation of the inocula to the must’s oenological properties. Finally, after the malolactic fermentation the inoculation with the mix of Lachancea thermotolerans and Torulaspora delbrueckii caused more changes in Tempranillo and Grenache wines while the early inoculation with Metschnikowia pulcherrima had more effects on Grenache wines. Therefore, the study was aimed to identify the fermentation effects of each inoculation strategy by using different non-Saccharomyces yeasts and different grape varieties.

The prospects of sparkling wine production by the ‘Champenoise’ method using alginate-immobilised yeast cells were examined. Grape varieties dominant in quantity were selected within the group of recommended and permitted varieties of Kutjevo vineyards, located in the eastern part of continental Croatia. Research revealed that there are no influential variations in the principal physicochemical and sensory characteristics between sparkling wines obtained through immobilised yeast and traditional sparkling method. The analysis of aroma compounds showed minor differences between samples. Observed oenological parameters assessed in the final products did not show any relevant oenological differences, with the exception of alcohol content, which was slightly higher in sparkling wines made with yeast cells immobilised with calcium alginate beads. According to this research, the sensory properties of the produced sparkling wines, compared to sparkling wine produced with free yeast, did not show any significant differences. On the full-scale obtained results indicate that some of the selected varieties can be sorted as suitable for the production of sparkling wine using immobilised yeast cells.

Abstract Oenological yeasts play a crucial role in the winemaking process by converting sugar into ethanol, carbon dioxide and flavor substances that contribute to the wine aroma profile. Eighty strains of yeast were isolated from Rosa roxburghii Tratt. Three of the indigenous yeast strains (numbered as C26, C31 and F110) were selected based on having the strongest fruity-aroma producing ability to further evaluate theirs oenological properties, and they were identified as Hanseniaspora uvarum based on morphological and molecular analyses. Strains tolerance results showed that the selected strains have glucose, citric acid and sulfur dioxide tolerances that are comparable to commercial Saccharomyces cerevisiae X16, but they are ethanol sensitive. Additionally, the H. uvarum strains had similar β-glucosidase production abilities to the control, but they do not produce hydrogen sulfide. Moreover, the selected H. uvarum strains reduced the acidity and increased the volatile aroma richness and complexity of R. roxburghii wine during laboratory-scale fermentation. Thus, the selected H. uvarum strains (C26, C31 and F110) show potential in the production of unique R. roxburghii wine.

The contamination of grape berries by Botrytis cinerea can drastically damage wine quality, in particular causing colour degradation. In musts obtained from botrytised grapes, SO2 addition is the main means of avoiding oxidation damage due to laccases excreted by the pathogen. However, consumers are becoming increasingly reluctant to accept SO2 addition to wine. Oenological tannins are used for fining wines because of their colloidal properties, and for wine colour stabilisation due to their ability to condense with anthocyanins. They are also known for their antioxidant and antioxidasic properties. They were thus investigated in the present study for their potential as an alternative to SO2 against laccase oxidation.The impact of various types of oenological tannins on musts and wines was studied once added to musts obtained from the Merlot cultivar, comprising 20 % and 50 % botrytised grapes. Laccase activity, antioxidant capacity, composition of phenolic compounds, spectrophotometric and CIELAB colour parameters were assessed in the musts and wines. Sensory analyses were also performed on 3-month-old wines to evaluate the visual, olfactory and gustative consequences of tannin addition. At a 50 % botrytisation rate, the addition of any type of oenological tannins (at a concentration of 100 g/hL) had no effect on laccase activity and did not protect phenolic compounds. However, at the same concentration and at a 20 % botrytisation rate, proanthocyanidin tannins from grape skin were found to be the most promising tannins with simultaneous protective effects, such as an inhibitory effect on laccase enzymes, protection of colour from complete degradation and preservation of some procyanidin compounds.Oenological tannins are promising candidates for protecting wines from Botrytis damage and they induce a differential effect according to their origin and structure. They could be used to reduce the amount of SO2 that is added during vatting. More research is needed to confirm and better understand the mode of action of various tannins at levels lower than the 20 % botrytised rate tested in the present study.

Wine fermentation processes are driven by complex microbial systems, which comprise eukaryotic and prokaryotic microorganisms that participate in several biochemical interactions with the must and wine chemicals and modulate the organoleptic properties of wine. Among these, yeasts play a fundamental role, since they carry out the alcoholic fermentation (AF), converting sugars to ethanol and CO2 together with a wide range of volatile organic compounds. The contribution of Saccharomyces cerevisiae, the reference organism associated with AF, has been extensively studied. However, in the last decade, selected non-Saccharomyces strains received considerable commercial and oenological interest due to their specific pro-technological aptitudes and the positive influence on sensory quality. This review aims to highlight the inter-specific variability within the heterogeneous class of non-Saccharomyces in terms of synthesis and release of volatile organic compounds during controlled AF in wine. In particular, we reported findings on the presence of model non-Saccharomyces organisms, including Torulaspora delbrueckii, Hanseniaspora spp,Lachancea thermotolerans, Metschnikowia pulcherrima, Pichia spp. and Candida zemplinina, in combination with S. cerevisiae. The evidence is discussed from both basic and applicative scientific perspective. In particular, the oenological significance in different kind of wines has been underlined.

Proposed dissertation thesis deals with wine and artisanal cheeses microbiology. The first part is focused on identification of yeasts isolated from grapes and musts during production of white and red wines. The grape varieties were grown under the integrated and organic farming on Moravian vineyard. Yeasts were identified by ITS-PCR-RFLP method (amplifying internal transcribed spacer ITS: ITS1, ITS2 and 5.8S rDNA) and unknown species were subjected to partial sequencing of ITS rDNA region. In total, 524 isolates were divided into 14 different species belonging to six genus were identified from. The first stages of fermentation process were characterised by predominance of non-saccharomyces species especially H. uvarum. Due to increased ethanol concentration strains of S. cerevisiae prevailed in the later phases of the process. Further, partial aim of this study was to isolate and to apply selected autochthonous S. cerevisiae strains as starter culture during controlled industrial wine fermentation process. Genus Saccharomyces was distinguished from other non-saccharomyces species by ITS-PCR-RFLP. Further, in order to distinguish Saccharomyces genus at the species and the strain level, several molecular methods were applied including PCR-fingerprinting (rep- and RAPD-PCR), species-specific primers (multiplex and touchdown PCR), LSU-DGGE and interdelta PCR. Species-specific primers enabled us to distinguish some species of the Saccharomyces sensu stricto complex. Furthermore, interdelta PCR seems to be useful tool for S. cerevisiae strains identification. Among 120 isolated autochthonous strains belonging to Saccharomyces genus, 45 different strains were identified. Based on its sufficient technological properties (osmo- and ethanol tolerance, low H2S production etc.), S. cerevisiae 1-09 strain isolated from grape berries coming from moravian vineyard was chosen. Strain S. cerevisiae 1-09 was tested in small amount of must and after that also during industrial fermentation of red and white wine production. Based on the results of chemical and sensorial analysis, the strain seems to be suitable for application as the starter culture for winemaking process. The final part of this thesis is focused on quantification and identification of the yeasts isolated from artisanal cheeses and their by-products coming from Western Balkan Countries. Isolated species were identified by ITS-PCR-RFLP, partial sequencing and by physiological tests. Among the 20 yeast species found, D. hansenii, C. zeylanoides and Y. lipolytica were found to be predominant. Moreover, we developed culture-independent, semi-quantitative technique based on construction of ITS-clone library from metagenomic DNA to investigate complex fungal communities associated with artisanal cheeses and their by-products. Novel technique is based on direct extraction of total DNA from the sample. This was compared with culture-dependent ITS-PCR-RFLP and culture-independent LSU-DGGE methods. The results highlighted the discrepancies among these methods. Finally, the divergences among applied methods were confirmed by correlation analysis and by indices of general biodiversity and dominance of species. ITS-clone library approach combines the advantages of cultivation-based analysis and LSU-DGGE with semi-quantification of fungal species without the requirement of their cultivation. This study might open new perspectives in direct and complex analysis of yeasts and moulds in food matrices.

L'utilisation de tanins œnologiques en vinification relève d’une pratique courante, bien que ceux-ci ne soient à ce jour uniquement autorisés dans le but de faciliter la clarification des vins et des moûts par l’OIV. En revanche, les tanins œnologiques peuvent aussi être utilisés à d’autres fins, expliquant l’existence d’une grande variété sur le marché. En ce sens, l'OIV à créer il y a quelques années, un groupe de travail afin de conduire une vaste étude sur les tannins œnologiques. L’objectif de cette thèse était donc de mener une étude exhaustive afin de déterminer dans un premier temps leur composition chimique et leur richesse en tanins. Dans un second temps leurs potentielles fonctionnalités ont été étudiées, en mettant l'accent sur leur activité antioxydante, leur capacité à stabiliser la couleur des vins et, enfin, leur activité antioxidasique. Concernant, la composition chimique, les principaux monomères, dimères, trimères et tétramères des tanins ont été identifiés et quantifiés par HPLC-MS-UV et LC-QTOF. La richesse en tanins a été estimée par différentes méthodes : IPT, Bate-Smith, méthyl-cellulose, Folin-Ciocalteu, méthode officielle de l'OIV et phloroglucinolyse. La capacité antioxydante a été mesurée par 5 méthodes (ABTS, CUPRAC, DPPH, FRAP et ORAC), tandis que la consommation d'oxygène a été déterminée à l'aide d'une méthode non invasive basée sur la luminescence. La mesure de l’activité laccase, la détermination du type d’inhibition et la caractérisation des laccases par électrophorèse SDS-PAGE, ont permis d’évaluer les propriétés antioxidasique des tannins œnologiques. La capacité des tanins œnologiques à stabiliser la couleur a été déterminée par l’induction d’effet bathochrome et hyperchrome ainsi que par le calcul de l’indice de copigmentation. Cet effet a été évalué pendant plusieurs jours, à différentes concentrations d’ethanol et à différents pH. Les résultats obtenus confirment que les tanins œnologiques et plus particulièrement les ellagitannins protègent le vin de l'oxydation, de par leur pouvoir antioxydant et capacité à consommer directement l’oxygène. Les tanins œnologiques, et plus particulièrement les gallotannins, permettent de stabiliser la couleur des vins rouges, en jouant le rôle de copigments. Enfin, les tanins œnologiques, et en particulier les tanins du raisin, constituent un nouvel outil afin d’inhiber ou précipiter les laccases produites par B. cinerea. Fruit de ces résultats, les résolutions de l'OIV OENO-TECHNO 17-612 et OENO-TECHNO 17-613, récemment acceptées, proposent d'inclure deux nouvelles fonctionnalités d'utilisation des tanins dans les moûts et les vins :• Contribuer à la protection antioxydante des composants du moût et du vin• Promouvoir l'expression, la stabilisation et la préservation de la couleur
The use of oenological tannins is a common practice worldwide in winemaking. However, up to date this use, is only authorized by the OIV to facilitate wines and must clarification. Nevertheless, oenological tannins are used for several reasons, explaining the existence of diverse tannins on the market. For all these reasons, OIV has begun few years ago to create a working group in order to conduct a large study on oenological tannins. Thus, the aim of this research was to carry out an exhaustive study to determine firstly the chemical composition and the richness in tannins of the oenological tannins. Secondly, their potential functionalities were studied, focusing on their antioxidant activity, their ability to stabilize and improve wine color and finally, their antioxidasic activity. Concerning chemical composition, the principal tannins monomers, dimers, trimers and tetramers were identified and quantified by HPLC-MS and LC-QTOF. The abundance in tannins was estimated by different methods: TPI, Bate-Smith, Methyl-cellulose, Folin-Ciocalteu, OIV official method and phloroglucinolisis. The antioxidant capacity was measured 5 methods (ABTS, CUPRAC, DPPH, FRAP and ORAC) meanwhile the oxygen consumption was measured using a non-invasive method based on luminescence. Antioxidasic property, was achieved by measuring first the laccase activity in winemaking, then by determined inhibition type and finally by laccase characterization precipitation by electrophoresis SDS-PAGE. The oenological tannins ability to stabilize the color was determined by their bathochromic and hyperchromic effect and by the calculation of the copigmentation index. Their color stabilization effect was evaluated during several days, different ethanol content and pH level. The results confirm that oenological tannins and specifically, ellagitannins, really protect wine against oxidation either because they exert antioxidant capacity and/or they consume directly oxygen. Moreover, oenological tannins can improve and stabilize red wines color acting as copigments, with gallotannins being the most efficient ones. In addition, oenological tannins, particularly grapes tannins, can be a new tool to inhibit the laccases produced by B. cinerea. As a fruit of these results, the OIV resolutions OENO-TECHNO 17-612 and OENO-TECHNO 17-613, just accepted, proposed to include two new functionalities of tannins uses in musts and wines:• Contribute to the antioxidant protection of must and wine components• Promote the expression, stabilization and preservation of color

博士
臺灣大學
食品科技研究所
95
More than hundreds of private wineries have been established since the Taiwan Tobacco and Alcohol Administration Act was enacted on April 19, 2000. It is essential to screen local wine yeast in order to develop quality wine with unique flavor. 364 yeasts were first isolated from plum, lichee, grape, Black Queen grape, orange, mango, pineapple, carambola and longan must with the supplement of sugar to 17 and 30。Brix, respectively. Among these yeasts, 123 yeasts with CO2 productivity greater than 10 mL after 24 h incubation in YMPG broth containing 10 % glucose were considered as potential yeast isolates. These 123 yeasts were then evaluated for their ethanol productivity in YMPS broth containing 20 % sucrose. Ten yeasts form Black Queen grape and longan with ethanol productivity greater than 5.0 % (v/v) selected for further fermentation properties test. Ethanol contents of fermented YMPS broth were all above 5.0 %(v/v), volatile acidity and turbidity all below 1.2 g/L and 20 NTU, may useable as Black Queen grape and longan wine starter. Black Queen grape is a main ingredient for red wine brewing in Taiwan. Seven yeasts identified as Saccharomyces cerevisiae by Biolog System with higher ethanol productivity were individually inoculated into Black Queen grape must to undergo fermentation at 25℃ for 14 days. The ethanol contents and volatile acidity in wine were above 15% (v/v) and below 0.7 g/L, respectively. Compared to commercial wine yeasts A, B and C, HP01 fermented red wine contained the highest total ester content, color intensity, taste grade, and overall preference value. On the other hand, HS13 fermented red wine contained the highest ethanol, higher alcohols, fatty acids and phenolic compounds content. The mtDNA restriction fragments profiles of these two wine yeast strains were different from those of other yeast strains. Due to their superiority in oenological characteristics, HP01 and HS13 can be applied in Black Queen red wine brewing to produce red wine with unique flavor. The effects of several protectants such as rice hull, wheat bran, skim milk, trehalose, and sodium glutamate on the viability of freeze-dried Saccharomyces cerevisiae strains HP01 and HS13 and their fermentation properties such as pH, volatile acidity, ethanol content, titratable acidity, color intensity, phenolic content and residual sugar during grape wine production were investigated. Besides, the effects of storage at 4℃ and 25℃ for 1 to 15 months on the viability and alcoholic fermentation properties of freeze-dried cells and wet cells were also studied. Results showed that the supplement of 10% wheat bran in freeze-drying menstrua could significantly increase the survival rate of freeze-dried HP01 from 25% to 46%. The simultaneous supplement of 10% wheat bran and 20% skim milk increased the survival rate of freeze-dried HP01 to 51%. For the freeze-drying of HS13, the simultaneous supplement of 20% skim milk, 5% honey, and 5% sodium glutamate showed the greatest survival rate, 80% while the survival rate of its control was 9.2%. The fermentation properties of freeze-dried yeasts were like their freshly prepared wet cells; namely, both of them produced 15% ethanol after 9 days fermentation at 25℃. At 4℃ storage, freeze-dried HP01 and HS13 could maintain their viability and fermentation properties as their wet cells for 15 months. While storing at 25℃, the storage lives of freeze-dried cells were less than 2 months.