Month: September 2019

Fiano, Greco and Falanghina grape cultivars differentiation by volatiles fingerprinting

By Andrea Carpentieri, Angelo Sebastianelli , Chiara Melchiorre , Gabriella Pinto, Marco Trifuoggi, Vincenzo Lettera and Angela Amoresano 

The biomolecular characterization of foods and beverages represent nowadays an intriguing task for the scientific community. While nonvolatile compounds of a wine, e.g. polysaccharides, organic acids, mineral salts and polyphenols, have a great impact on the mouthfeel with acidity and salinity perceptions and astringency, the volatile component is the main responsible of wine aroma that contributes to the peculiar recognizability of a vine. Food aroma is the result of the complex interaction of small volatile molecules and odor receptors [1] and, although its perception might be affected by subjectivity, it is considered as the first step in quality assessment. A common practice for the recognition of wines is in fact based on the flavors recognition: this peculiar capacity of tasters needs to be properly trained and developed. The characteristic smell of wines aroma come from grapes; pedoclimatic conditions and viticultural practices can enormously influence the varietal flavorings [2, 3]. Volatile molecules are secondary metabolites of the plant, i.e. they do not participate in the metabolic processes essential for the life of the plant itself but they have a crucial role in the defense mechanisms of the plant against the adversities characterizing the environment in which they live [4, 5]. The ecological function of secondary metabolism is expressed in the defense role that these substances have with regard to the biotic environment due to their irritating, toxic and repellent properties. During the evolution, plants have developed systems and strategies for growth and survival [6, 7]. The stimulation of secondary metabolism takes place at the expense of the growth of the plant, as it hampers part of the nourishment towards defense substances. Secondary metabolites can therefore be considered as available molecules for growth and development, but are indispensable for the survival of the species.

 

On a total 800 volatile compounds identified in wines (terpenoids, phenols, alcohols, esters, aldehydes, ketones, lactones) only few of them contribute to the wine bouquet [8-11]. The olfactory impact, considered as the threshold of perception of each individual compound, is dependent on chemical nature of molecule as well as its concentration [11]. In fact, some compounds present in trace amounts may have a greater impact than other aromatic compounds present in higher concentrations [11].
The study of the volatile compounds in grapes has been scarcely examined unlike that of wine [12, 13] but it is equally important for the characterization of a specific cultivar [13, 14]. The main reason for this lack of informations, relies in the fact that within the berries, the majority of volatile molecules are still in their glycosylated form[15-19]. During fermentation oligosaccharides are hydrolyzed thus releasing the free volatile molecules.
Recently, by using mass spectrometry techniques we outlined the proteomic profile [20] of three different cultivars of Vitis vinifera peculiar of south Italy (Campania) used for white wine production (Fiano, Greco and Falanghina) showing significant changes in protein expression along the ripening process. On the same set of samples, the molecular profiling of the volatile fraction was outlined by Solid Phase Micro Extraction hyphenated with Gas Chromatography-Mass Spectrometry (SPME/GC-MS). In a single experiment, more than 60 heterogeneous analytes were captured by SPME and then unambiguously identified by GC-MS. The analytical workflow adopted in this study (Fig.1) can be extended to the typization of different foods and beverages thanks to its high sensitivity, reproducibility and accuracy.
The relative quantification (based on chromatographic peak areas) of identified analytes, showed the trend for each molecule during maturation process for each cultivar. PCA, performed on the peak area of the volatile compounds identified by GC-MS for each sampling date of the three different cultivars, show a peculiarity of the biomolecular pattern of Fiano and a good overlap between Greco and Falanghina.

Fig.1 The workflow adopted for the volatiles fingerprinting of selected cultivars

Analytes were divided into five categories and then we plotted the average area of each class of compounds to monitor their trends. Among identified compounds, we focused on some of the aromatic descriptors, which resulted to be present in the three samplings of each cultivar (Tab. 1). These results were then compared with data from the other cultivars. For Falanghina, during the maturation process, we observed a general decrease of aldehydes, alcohols (except for hexanal, 2-hexen-1-ol e 1-hexanol), terpenes (except for eucalyptol) and esters; the same behavior cannot be observed for norisoprenoids. The same trend for the majority of compounds was observed in Greco; butanol, 3-methyl, pentanal, hexanal, 5-hepten-2-one, 6methyl represent an exception in the general behavior. As for Fiano, the general trend of molecules is not linear as the ones described before. For this cultivar, we could observe a reduction in esters amount.
While the majority of volatile compounds are glycosylated within grapes [18, 19], molecules identified in this paper represent the non-glycosylated (therefore more volatile) fraction. Glycosylated volatiles pass from the grape to the wine where they undergo chemical and enzymatic hydrolysis, which liberates terpenes and norisoprenoids from the sugar making them volatile [21]. This process explains why the volatile component of the grapes is composed of only few molecules, compared to the complexity of the compounds identified in wine, where not only the varietal component but also the esters and alcohols produced by the yeast are found.
The development of fast and simple analytical approaches and their application on real samples has a key role in food quality assessment and product typization. The increasing demand of products in the food market led the producers to introduce new and intensive farming techniques that, in turn, introduced a higher level of complexity among existing cultivars.
As a whole, our data suggest that the typization of edible products on a molecular level is nowadays possible and of fundamental importance not only for the safeguard of DOP/IGP products but also for preserving local economies.

Read more about this study in: DOI: 10.1016/j.heliyon.2019.e02287

Tab.1 Unique aromatic descriptors characterizing selected cultivars.

Dr. Andrea Carpentieri graduated at the University of Naples Federico II in 2002 in Biochemistry.
2004-2007 - PhD in chemical sciences (XX cycle) at the Department of Organic Chemistry and Biochemistry, University of Naples "Federico II", tutor Prof. P. Pucci.
2008-2010 Research Associated, Boston University School of Medicine tutors: Prof. J. Samuelson, Prof. P. Robbins and Prof. C.E. Costello.
2011- Fellow at the Department of Organic Chemistry and Biochemistry, University of Naples "Federico II", tutors Prof. P.Pucci and Prof. A. Amoresano).
2011-Visiting Researcher, Boston University School of Medicine tutors: Prof. J. Samuelson, Prof. P. Robbins and Prof.C.E. Costello.
20/12/2011-present Assistant Professor, Department of Chemical Sciences, University of Naples "Federico II".
His research activity is devoted to the analysis of biomolecules and their interactions in complex biological matrices. These studies are carried out by integrating classical biochemical procedures, with advanced bio molecular mass spectrometric procedures. Reviewer of many scientific journals and PhD theses. The research activity is documented by the publication of over 45 articles in international peer review journals dealing with different aspects of analytical biochemistry.
Scopus Author ID: 57202563415
acarpent@unina.it

 

References
1. Genovese, A., et al., Sensory properties and aroma compounds of sweet Fiano wine. Food Chemistry, 2007. 103(4): p. 1228-1236.
2. Styger, G., B. Prior, and F.F. Bauer, Wine flavor and aroma. Journal of industrial microbiology & biotechnology, 2011. 38(9): p. 1145.
3. Molina, A.M., et al., Influence of wine fermentation temperature on the synthesis of yeast-derived volatile aroma compounds. Applied Microbiology and Biotechnology, 2007. 77(3): p. 675-687.
4. Dunlevy, J., et al., The production of flavour & aroma compounds in grape berries, in Grapevine molecular physiology & biotechnology. 2009, Springer. p. 293-340.
5. Ali, K., et al., Metabolic constituents of grapevine and grape-derived products. Phytochemistry Reviews, 2010. 9(3): p. 357-378.
6. Qiu, W., A. Feechan, and I. Dry, Current understanding of grapevine defense mechanisms against the biotrophic fungus (Erysiphe necator), the causal agent of powdery mildew disease. Horticulture research, 2015. 2: p. 15020.
7. Bennett, R.N. and R.M. Wallsgrove, Secondary metabolites in plant defence mechanisms. New phytologist, 1994. 127(4): p. 617-633.
8. Sánchez-Palomo, E., M.C. Diaz-Maroto, and M.S. Perez-Coello, Rapid determination of volatile compounds in grapes by HS-SPME coupled with GC–MS. Talanta, 2005. 66(5): p. 1152-1157.
9. Sagratini, G., et al., Comparative study of aroma profile and phenolic content of Montepulciano monovarietal red wines from the Marches and Abruzzo regions of Italy using HS-SPME–GC–MS and HPLC–MS. Food Chemistry, 2012. 132(3): p. 1592-1599.
10. Bosch-Fusté, J., et al., Volatile profiles of sparkling wines obtained by three extraction methods and gas chromatography–mass spectrometry (GC–MS) analysis. Food Chemistry, 2007. 105(1): p. 428-435.
11. Francis, I. and J. Newton, Determining wine aroma from compositional data. Australian Journal of Grape and Wine Research, 2005. 11(2): p. 114-126.
12. Razungles, A., et al., Quantitative studies on terpenes, norisoprenoides and their precursors in several varieties of grapes [carotenoids]. Sciences des Aliments, 1993.
13. Gürbüz, O., J.M. Rouseff, and R.L. Rouseff, Comparison of aroma volatiles in commercial Merlot and Cabernet Sauvignon wines using gas chromatography− olfactometry and gas chromatography− mass spectrometry. Journal of Agricultural and Food Chemistry, 2006. 54(11): p. 3990-3996.
14. Pozo-Bayón, M., et al., Polydimethylsiloxane solid-phase microextraction–gas chromatography method for the analysis of volatile compounds in wines: Its application to the characterization of varietal wines. Journal of Chromatography A, 2001. 922(1-2): p. 267-275.
15. Palomo, E.S., et al., Contribution of free and glycosidically-bound volatile compounds to the aroma of muscat “a petit grains” wines and effect of skin contact. Food Chemistry, 2006. 95(2): p. 279-289.
16. Selli, S., et al., Aroma components of cv. Muscat of Bornova wines and influence of skin contact treatment. Food Chemistry, 2006. 94(3): p. 319-326.
17. Dimitriadis, E. and P. Williams, The development and use of a rapid analytical technique for estimation of free and potentially volatile monoterpene flavorants of grapes. American Journal of Enology and Viticulture, 1984. 35(2): p. 66-71.
18. Gunata, Y., et al., The aroma of grapes I. Extraction and determination of free and glycosidically bound fractions of some grape aroma components. Journal of Chromatography A, 1985. 331: p. 83-90.
19. Nasi, A., et al., Identification of free and bound volatile compounds as typicalness and authenticity markers of non-aromatic grapes and wines through a combined use of mass spectrometric techniques. Food Chemistry, 2008. 110(3): p. 762-768.
20. Carpentieri, A., et al., Mass spectrometry based proteomics for the molecular fingerprinting of Fiano, Greco and Falanghina cultivars. Food Research International, 2019. 120: p. 26-32.
21. Mateo, J. and M. Jiménez, Monoterpenes in grape juice and wines. Journal of Chromatography A, 2000. 881(1-2): p. 557-567.

 

Posted by in Chemistry

Social Media Marketing in promoting Wine Tourism in Langhe, Italy

By Magali Canovi

As wine continues to play an important part in people’s lifestyles, an increased interest in visiting the places of production has been witnessed, resulting in a rapid growth in popularity of wine regions around the world (Molina et al., 2015). As a consequence, numerous wine regions – from Napa Valley in the U.S., Barossa Valley in Australia, Langhe and Tuscany in Italy to Burgundy, Bordeaux and the Champagne region in France – are leveraging their enogastronomic excellence to promote their territory and develop as a tourism destination. Wine is considered a central element in the development and promotion of tourism and is likely to contribute to the creation of wealth at the national, regional and local level (O’Neill & Charters 2008). While wine tourism allows visitors to experience a distinctive product, it also promotes economic growth at the regional level and provides local wineries with the opportunity to increase their sales and develop tourism-related businesses Wine tourism has thus been acknowledged to be an ‘extension of the complex relationship between wineries, wine regions and visitors/consumers’ (Bruwer & Alant, 2009).

 

Langhe, situated in the southern part of the Piedmont province (see fig. 1), is a region long renowned for its quality wines. It is characterised by ‘old world’ winemaking practices and traditions. Langhe secured its reputation during the early 1990s when Barolo was recognised as ‘one of the world’s great wines’ (Rosso, 2014), which led to an increased interest by tourists – initially from central Europe – in visiting these places of wine production. The inscription on the UNESCO World Heritage List in 2014 of the Langhe-Roero and Monferrato vineyards further enhanced Langhe’s reputation as an internationally renowned tourism destination. In fact, the region continued to attract enogastronomic tourists from around the world – as demonstrated by an 81% growth of tourist arrivals to the region between 2006 and 2016 (DMO Piemonte, 2017).
At the local level, Langhe winery owners have started to take advantage of this opportunity, offering a number of tourism-related activities, such as winery visits, wine tastings, cellar-door sales, B&Bs and/or restaurants. Although wine tourism is seen as a lucrative industry, creating wealth and generating substantial economic growth (O’Neill & Charters, 2008), the success of wine tourism – particularly at the local level – largely depends on how effective and efficient marketing and promotion strategies are implemented and exploited. In Langhe, due to the continuous development of the wine tourism industry, wineries have increasingly leveraged social media for boosting their visibility and attracting a growing number of tourists to their winery.
 

 

Twenty interviews were conducted with winery owners, regarding their perceptions of social media in promoting wine tourism in Langhe. The large majority of participating wineries had developed a corporate website (95%) and is currently engaging in a combination of social networking sites, including Facebook (80%), Instagram (55%) and Twitter (50%). Wineries’ websites and social networking sites are extensively used to share product and service information, display photographs, promote the winery’s products and tourism activities, share family stories as well as sell products and services online.

Winery owners’ attitudes were shaped by their perceived benefits of as well as barriers to the adoption of social media. Perceived benefits include the social, economic and emotional value gained from the use of social media platforms, while the barriers relate to the strong agricultural mentality among winery owners as well as the time-consuming nature of social networking sites.

 

The empirical evidence showed that the use of social media platforms is likely to provide winery owners with social benefits such as greater connectedness, engagement in social interaction, building long-term relationships/friendships with tourists, as well as improved social image and reputation of the winery. Besides the social value gained from the use of social media platforms, the importance of the economic benefits of social media became evident. Particularly, winery owners started to develop online stores on their websites to encourage tourists and consumers to buy their wines online.
Although the majority of interviewed winery owners portrayed a favourable attitude towards and perception of social media, a number of barriers related to the adoption and use of social media were also found. The engagement in social media activities has been found to conflict with owners’ dominant agricultural mentality. Conventional winery owners – particularly the older generation – display an old/traditional way of thinking and are reluctant to change their practices and adopt social media as a marketing tool. Indeed, in some cases, winery owners highlighted their reluctance to engage in social media activities, noting that they have no need to include social media as part of their marketing strategy, due to their favourable market position and high-quality wine production. Inextricably linked to the dominant agricultural mentality, some winery owners perceive the time-consuming nature of social media as a barrier of its effective adoption.
All in all, however, the findings reveal that winery owners undoubtedly recognize the opportunities and benefits of social media in promoting their wine tourism activities, thus embracing a positive perspective towards social media. The majority of participating wineries has adopted and implemented - in addition to their corporate website – a combination of social media tools, such as Facebook, Instagram, and Twitter. Indeed, a generally high awareness among winery owners emerged, regarding the crucial role of the web 2.0 at each stage of wine tourists’ decision-making process: from initial information seeking to pre and post communication with tourists. Winery owners perceive social media as a beneficial tool for marketing and promoting wine tourism, as it assists them in generating interest, increasing visibility, improving reputation and attract an increasing number of tourists to the winery. Although the strong agricultural mentality and the time-consuming nature of social media were identified to be fundamental barriers of adoption, in no instance did winery owners question the usefulness and efficiency of social media platforms.
Read more about this study at: https://doi.org/10.1080/10548408.2019.1624241

Magali Canovi is a research fellow at the ESCP Europe Business School in Turin, Italy. She received her Ph.D. in Tourism Management from the University of Chester (UK). She holds a Masters degree in International Hospitality Management from the University of Derby (UK). Her research interests include wine tourism, rural tourism diversification, identity in tourism and stakeholders’ attitudes towards tourism development, with a particular focus on family businesses. She has worked on a number of projects in Italy, focusing on how family businesses engage in strategic decision-making, notably within the context of wine tourism. She is currently working on multiple projects in this area linked to rural tourism, entrepreneurship and family business.

References
Bruwer, J., & Alant, K. (2009). The hedonic nature of wine tourism consumption: an experiential view. International Journal of Wine Business Research, 21(3), 235-257.
DMO Piemonte (2017). Rapporti statistici dei flussi turistici in Piemonte.
http://www.piemonte-turismo.it/documenti/market-research-statistics/rapporti-statistici-dei-flussi-turistici-in-piemonte/
Molina, A., Gómez, M., González-Díaz, B., & Esteban, Á. (2015). Market segmentation in wine tourism: strategies for wineries and destinations in Spain. Journal of wine research, 26(3), 192-224.
O’Neill, M., & Charters, S. (2000). Service quality at the cellar door: Implications for Western Australia’s developing wine tourism industry. Managing Service Quality: An International Journal, 10(2), 112-122.
Rosso, M. (2014). Barolo – The Jewel of the Langa. Turin: Omega Edizioni

 

Posted by in Economy | Marketing

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.
Follow everything in our webpage: https://www.science-and-wine-conferences.com/

 

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. orcid.org/0000-0001-7204-6006

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:https://www.sciencedirect.com/science/article/pii/S0963996919303862

 

 

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.

References

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

https://www.mdpi.com/2311-5637/5/3/72

https://www.mdpi.com/journal/fermentation/special_issues/non-saccharomyces

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