Month: September 2019

Wine Consumption in the Mediterranean Diet: A clarification about health effects

By Paula Silva

Science & Wine is a science communication project in the wine research field. Promote the discussion of hot topics is one of project goals and one of most challenge ones too. From our experience, to be effective this kind of discussion should be extended to all that are interested in and it will be more productive in a live event. In fact, some of issues were approached both in the post format and in live events namely Wine Science Cafés and in the 1st Science & Wine Congress, and the live formats were most successful to engage people. Placing scientific work within a larger context can be gratifying as well as stimulating for all participants. As mention above, this live approach is essential to discuss controversial topics such as wine consumption. Indeed, if you search for wine health effects, you're bound to find mixed messages. Wine is part of the Mediterranean Diet, which emphasizes fruits, vegetables, nuts, grains, legumes, seafood and olive oil consumption. Several studies demonstrated protective associations between moderate drinking and cardiovascular disease, atherosclerosis, hypertension, certain types of cancer, type 2 diabetes, neurological disorders, and the metabolic syndrome. Definition of moderate alcohol consumption is often differently in different countries, and no conclusive recommendations exist regarding moderate wine consumption.
The clarification of this issue motivated Science & Wine to promote the 1-Day Conference “Wine Consumption in the Mediterranean Diet: A clarification about health effects” be held in Porto at June 4 of 2020. The conference will take place in the Association of Port Wine Companies.
This conference already has the institutional support of: University of Porto, UNESCO (Chaire: Culture et Traditions du Vin), Association of Port Wine Companies and Association Nutrition Méditerranéenne et Santé.
In the morning will occur a Plenary Session during which world-renowned scientists deliver reports on their research in Mediterranean Diet effects on human health, underlining the effects of a moderate and regular wine drinking considering the interactions between wine and important dietary factors such as olive oil, fish, fruit and vegetables. In addition to health and nutrition effects, sociocultural wine value and local economic returns will be also addressed. Already confirmed are the following speakers: from Portugal Prof. Eliana Alves (University of Aveiro); from Italy Prof. Giovanni de Gaetano (Istituto Neurologico Mediterraneo Neuromed Pozzilli) and Prof. Francesco Visioli (University of Padua); and from Spain Prof. Lluis Serra-Majem (University of Las Palmas de Gran Canaria), Prof. Ramon Estruch (Barcelona University) and Prof. Celestino Santos-Buelga (Universidad of Salamanca).



Figure 1. Confirmed Speakers in he 1-Day Conference “Wine Consumption in the Mediterranean Diet: A clarification about health effects”

Figure 2. Chef Hélio Loureiro

Lunch menu will be signed by Hélio Loureiro, a famous Portuguese chef, a menu inspired on the flavourful and healthy foods of the Mediterranean. The afternoon will start with the best five oral communications chosen by the scientific committee among the ones submitted. This session will be followed by an intimate roundtable session geared for a lively discussion.

Science & Wine aims to encourage scientists to progress into their professional careers by raising awareness of science to the wider community. This conference offers an opportunity to researchers to present their research work develop their skills for science communication. Researchers (presenting authors) that want to take this opportunity authors must be registered in the conference. After they must wait until April to know if their submitted abstract was one of the 5 selected to by scientific committee to be presented as oral communication at the conference. The best 3 presentations will win a prize that will be announce sooner.
I hope to see you all in “Wine Consumption in the Mediterranean Diet: A clarification about health effects” conference.
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Paula Silva is Assistant Professor in the Laboratory of Histology and Embryology, Department of Microscopy, in the Institute of Biomedical Sciences Abel Salazar (ICBAS) of University of Porto (UPorto). Teaching experience covers: Histology and Embryology (Human and Comparative), Animal Models of Human Disease, and Science Communication. Director of the continuing training course “Science communication – Life and health sciences” (6ECTS) and of the continuing training unit “Animal Models of Human Disease” (6ECTS). She obtained her PhD in Biomedical Sciences in UPorto. Paula Silva presents in her CV 23 original articles published in journals indexed in the Science Citation Index (SCI), 1 book chapter, participation in some I&DT projects, and numerous works in many national and international congress. At present, her main research topic is the influence of moderate consumption of wine on chronic diseases, particularly, neurodegenerative diseases.

Posted by in Health

Mapping the evolution of Chenin Blanc and Sauvignon Blanc wines

By Astrid Buica and Mpho Mafata

Many changes happen from the moment a wine is bottled until it is poured into a glass. These changes are dictated by wine composition, the conditions in which the wine is transported and stored, and the duration of these conditions. Wine composition itself is a result of many factors – from cultivar, grape growing conditions, to winemaking procedures and wine age. The question is, do different wines change in a similar manner when placed in similar conditions, regardless of the initial composition?
To answer these questions, we decided to evaluate the changes for two cultivars, one aromatic (Sauvignon Blanc) and one neutral (Chenin Blanc). All selected wines were young, unwooded, cold stabilized, and bottled under screwcap in the month prior to the beginning of the study. The wines were sourced from six wineries that worked with both cultivars. The wines were kept in their designated storage conditions (room temperature, 15°C, 25°C) for 3 and 6 months, and the original wine was considered the control or time 0 (T0). Once the storage time was reached, the bottles were moved into a -4°C room to avoid further changes while avoiding freezing.
The sensory evolution of the wines was measured using Pivot©Profile (Thuillier et al., 2015). We chose the method due to its concept: each wine is described in comparison to the reference (or Pivot), in our case T0, and the judges mark the attributes as ‘more than’ or ‘less than’ in the control. The resulting sensory profile of the samples is not a general profile of the wine, but rather in terms of what changed in comparison to the reference. In our case, what changed in the wines since the experiment started. To us, this method was an excellent choice for a fit-for-purpose approach.


Figure 1. Example of a heatmap generated using the Pivot©Profile results for the Chenin Blanc wine set from FRV. The rest of the code indicates storage time and temperature conditions.

The visuals that accompany the results are self-explanatory and intuitive: a heatmap (Figure 1). It can be read horizontally or vertically, depending on whether the wine profile or a specific attribute need to be described in relation to the T0 wine. The heatmap illustrates how samples and attributes relate to each other in the same set. More practically, we can see which of the wines changed in a similar manner to each other and which changed the most (or least) compared to the original wine and how. This was a simple and elegant idea for which we have to thank our colleagues and co-authors, Dr Jeanne Brand and Prof Martin Kidd (Brand, 2019). We also used the more classical approach of Correspondence Analysis (CA) to work with the data.
At the end of this stage, twelve sensory maps were produced, one for each set of wines, six for Chenin Blanc and six for Sauvignon Blanc. At this point, even though we have represented each wine’s evolution individually, the overarching question was still not answered – did the wines change in a similar manner?
The work was taken a step further, investigating this time the patterns of evolution of the wine sample sets. To this end, we had to assess the similarities in the configurations obtained for the individual sets illustrated by the maps. Statistically, regression vector (Rv) coefficients were calculated pair-wise for the sets, which, in turn, were used for a three-dimensional representation of Multidimensional Scaling (MDS). Practically, we obtained a 3D map in which the sample sets were now reduced to one point. All the information acquired during the experiment was condensed to the level where we could see which wines changed similarly and which did not, regardless of the initial wine profile. The closer the points on the 3D space, the more similar the pattern of evolution of the sets represented. An interesting finding was that, overall, Chenin Blanc wines had a more consistent pattern of evolution than Sauvignon Blanc wines.
The chemistry of the wines, related to factors such as clonal differences, grape ripeness at harvest, terroir, and winemaking practices, was highly variable between the initial wines. At the end of the experiment, we could still demonstrate that the storage conditions had similar effects on all the wines included in the experiment, with the exception of one Sauvignon Blanc and one Chenin Blanc wines, both from the same winery.

To learn more about this work:



Dr. Buica is a researcher in Oenology specialized in Analytical Chemistry applied to wine and related matrices, coordinator of Analytical activities and manager of the Analytical Laboratory in the Department of Viticulture and Oenology at Stellenbosch University, South Africa. She graduated in 2000 as Chemist specialized in Analytical Chemistry at the University of Bucharest, Romania. She obtained her PhD in Analytical Chemistry at the Stellenbosch University, South Africa. Dr Buica decided to follow another path when the opportunity arose in the Institute for Wine Biotechnology and the Department of Viticulture and Oenology at Stellenbosch. An Analytical Chemist at heart, Dr. Buica dedicated most of her time to the Analytical activities and laboratory in the Department, developing methods for routine analysis of wine and related matrices. In the recent years, she has decided to slightly shift her focus to include Sensory Science in her work, to bring together these two fields relevant to Wine Sciences. Most of her projects have an important Sensory and Analytical component to them, in an effort to give a more comprehensive view to the evaluation of wine. As such, she delved into untargeted analyses (HR-MS, IR, NMR) and rapid sensory methods for rapid wine profiling, and into the fields of Chemometrics and Data Fusion.

Miss Mpho Mafata is a PhD student in the Department of Viticulture and Oenology at Stellenbosch University, South Africa. She graduated from the University of Cape Town as a Chemist and then obtained her MSc at Stellenbosch University in 2017 with the thesis “The effect of grape temperature on the phenolic extraction and sensory perception of Méthode Cap Classique wines”. Under Dr. Buica’s supervision, Miss Mafata is continuing her studies, this time in the field of Data Fusion, working with applications in both Sensory Science and Analytical Chemistry. She is already the author of a number of papers and conference participations that showcase her work in this challenging field.


Brand, J., 2019. Rapid sensory profiling methods for wine : Workflow optimisation for research and industry applications. PhD dissertation, Stellenbosch University.
Thuillier, B., Valentin, D., Marchal, R. & Dacremont, C., 2015. Pivot(c) profile: A new descriptive method based on free description. Food Qual. Prefer. 42, 66–77.

Posted by in Enology

Enological repercussions of non-Saccharomyces species in wine biotechnology

By Antonio Morata

The use of non-Saccharomyces yeasts in enology has increased since the beginning of the current century because of the potential improvements they can produce in wine sensory quality. Several review articles have described the potential of some non-Saccharomyces species [1–3] and the suitable criteria to select them [4,5] according to the effects of the species on wine color, aroma, body or structure. Most non-Saccharomyces species have low fermentative power, which makes it necessary to use them in sequential fermentations with S. cerevisiae to completely deplete the sugars. Moreover, some of them have slow fermentation kinetics, which is a drawback for a competitive implantation in must containing S. cerevisiae indigenous populations. Emerging technologies to control wild indigenous yeasts can facilitate the development, growth and fermentative activity of the inoculated non-Saccharomyces yeasts and, therefore, the suitable expression of their metabolic properties [6]. This special issue is focused on the description and review of several non-Saccharomyces species with great potential in wine biotechnology, some of which are frequently used at the winery scale, but also produced industrially as dried yeast or liquid inoculant [7].
Wine acidity, especially the pH, is a key parameter in wine that controls microbial development and chemical stability. Traditional pH control is driven by acidification processes with tartaric acid or modern ion exchanger techniques, which unfortunately affect sensory quality. The biological modulation of wine acidity can be done effciently by several non-Saccharomyces species, by the production of lactic acid by Lachancea thermotolerans or succinic acid by Candida stellata, the demalication by Schizosaccharomyces pombe or Pichia kudriavzevii, and the control of volatile acidity in sequential fermentations with Torulaspora delbrueckii or Zygosaccharomyces florentinus highlight the possibilities of non-Saccharomyces in the improvement of wine acidity [8].


Biological acidification by L. thermotolerans is a powerful tool to control pH in warm areas [9]. The production of acidity is performed from sugars and the product lactic acid is a stable metabolite during winemaking but also through stabilization and aging. The formation of several metabolites with sensory repercussions has also been described in this species. Acidification by L. thermotolerans is a natural biotechnology that helps to keep lower and more effective levels of molecular and free SO2. Currently, in our laboratory we have selected strains of this species able to ferment at more than 12% potential alcohol,which opens the door to single fermentations with single inoculums of L. thermotolerans.

Wine deacidification by metabolization of malic acid is an essential step in red winemaking. This acid is unstable during stabilization and aging, and can produce microbial hazes if not eliminated previously. Usually, malic acid is transformed into lactic acid by malolactic fermentation produced by lactic acid bacteria, mainly Oenococcus oeni, due to the specific composition of wine. Alternatively, S. pombe is able to metabolize malic acid by the maloalcoholic fermentation pathway. The advantages are the fast and effcient degradation of malic acid and at the same time S. pombe can produce the alcoholic fermentation. Moreover, its use reduces the formation of biogenic amines. Also, the peculiar metabolism of S. pombe facilitates the formation of vitisin A pyranoanthocyanin pigments, with positive effects on color stability [10].


Figure 2: Non-Saccharomyces fermentation.

Among the pioneer species used in enology is T. delbrueckii, with medium fermentative power, some strains reach 9% 10% in alcohol with a high fermentation purity. The production of acetic esters and other specific aromas makes this yeast a key option to improve wine aroma, but it also has interesting effects on the body and structure [11]. Recently, it has been used in sparkling wines to make more complex base wines, whilst also increasing the structure during bottle aging [12].
The production of acetic esters is an interesting strategy to improve a wine’s aromatic profile. The use of Wickerhamomyces anomalus helps to increase the contents of several esters, specifically 2-phenyl-ethyl acetate, with positive floral profiles [13]. The main drawback of this species is the high production of acetic acid, which can be partially controlled with suitable strain selection, but also through its use in sequential fermentation with S. cerevisiae. Apiculate species, such as the Hanseniaspora/Kloeckera genera, are also described as strong producers of acetate esters, and many species enhance the formation of 2-phenyl-ethyl acetate; some also produce benzenoids or nor-isoprenoids. Moreover, they tend to have an interesting effect on structure by producing full bodied wines [14]. Some of these species, as well as Metschnikowia pulcherrima and C. stellata, are able to release extracellular hydrolytic enzymes, such as -glucosidases or c-lyases, that help improve the varietal aroma by releasing free terpenes or thiols [15,16]. A wide pool of enzymatic activities can also be found in saprophytic Aureobasidium pullulans, several of these enzymes can be purified with useful applications in enology [17]. A. pullulans is a typical yeast-fungus that can be found in the indigenous microbiota of the berry together with the apiculate genera Hanseniaspora/Kloeckera.

Spoilage yeasts such as Zygosaccharomyces rouxii, Saccharomycodes ludwigii or Brettanomyces bruxellensis may be diffcult to handle at specific winemaking stages. Usually, the main concern of the enologist is their control and elimination from musts and wines, but also the analysis of their populations and their main marker metabolites. However, these non-Saccharomyces species sometimes have interesting applications in fermentative industries. Zygosaccharomyces rouxii is a frequent osmophilic spoilage species that causes re-fermentations in sweet wines and other drinks, such as fruit juices and soft beverages. Its control can be done using additives as DMDC, emerging antimicrobials as LfcinB, or cold pasteurization processes as DBD, US, UHPH or PEFs [18]. Saccharomycodes ludwigii is a strong fermenting yeast able to completely finish grape sugars; it also shows a strong resistance to high SO2 levels. Some interesting applications are now being described, such as the use of this species in the reduction of the alcoholic degree of beers or in the production of ciders. In enology, the production of off-flavors reduces a lot the potential use of S. ludwigii in wine fermentation. The control measures used to reduce its prevalence in wines are the use of emerging physical technologies, chemical additives such as DMDC, but also natural products such as chitosan or biological control with killer yeasts [19]. The use of biological control with yeasts able to produce antimicrobial peptides is a novelty in the elimination of Brettanomyces spp. [20]. This spoilage yeast degrades the sensory quality of the wine as it develops during barrel aging, usually affecting more expensive wines by producing several unpleasant molecules [21]. Conventional control is based on the use of SO2 and hygiene measures, however both parameters are diffcult to control and maintain during long periods in diffcult materials such as barrel wood. The use of C. intermedia as a selective bio-controller is a natural way to reduce the damages produced by Brettanomyces. Bio-protection and biological management of spoilage and undesired yeast can be also done by using M. pulcherrima, the production of the pigment pulcherrimin and their effect on iron chelation helps to eliminate competitive yeasts in grapes or at the beginning of fermentation [15].

Figure 2: Fermentation Journal.

If the twentieth century saw the explosion of S. cerevisiae applications, non-Saccharomyces yeasts open up a world of new biotechnologies in the twenty-first century, including improved fermentations, with more complex and differentiated sensory profiles in wines, bioprotection applications, enzymatic activities, acidity modulation, improvement of aging processes, reduction of toxic molecules and additives, and many other possibilities to discover. Some of these potentials contribute to the adaptation of wine to regions and terroirs, even to the ecological changes produced by global warming.

Funding: This research received no external funding.
Conflicts of Interest: The authors declare no conflict of interest.

Guest Editor
Prof. Dr. Antonio Morata
Department of Food Science and Technology, Universidad Politécnica de Madrid (UPM), Madrid, Spain
Interests: enology; wine technology; winemaking; food technology; emerging preservation technologies


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Posted by in Enology, Food Science and Technology