Application of portable micro near infrared spectroscopy to the screening of extractable polyphenols in grape skins: A complex challenge.

By Berta Baca-Bocanegra, José Miguel Hernández-Hierro, Francisco José Heredia, Julio Nogales-Bueno
The levels of extractable phenolic compounds of red grapes (Vitis vinifera L.) vary considerably. Currently, interest has shifted to the development of portable vis/NIR systems, innovation in optical system design and miniaturization for its approachable use in the field. In 2016 and 2017 vintages, spectra of intact grapes and grapes skins were recorded at harvest time using a portable micro NIR spectrophotometer. Several chemometric approaches have been used for spectral interrogation and evaluation of the device. Spectral data have been correlated with red grape skin extractable polyphenols. It was concluded that several factors affect the use of the portable micro NIR device for the “in vineyard” screening of extractable polyphenols in red grape skins. Environmental and physiological conditions should be considered to evaluate and remove factors that hamper a good sorting the berries according to their extractable polyphenol contents. Find out more

Chronobiology in the vineyard

By Suzy Rogiers and Francesca Moroni
Evidence for chronobiology can be found in many aspects of viticulture. Buds swell and burst every spring with warmer temperatures and longer days. The onset of flowering is also driven by changes in day length and its timing is important to reproductive success. Grapevines can sense longer days in spring through the light receptors located in green tissues. Alternatively, leaf senescence is activated as day length shortens in autumn and the vine prepares for dormancy. Co-ordination between cells and tissues of the shoot tips, leaves, woody components and roots is critical to successful regulation of growth and development. This may explain the presence of multiple clocks in different tissue types within any one organism. Find out more

Can panelists’ sensitivity be improved?

By Astrid Buica and Marianne McKay

The odor detection threshold (ODT) of a compound is the lowest concentration at which individuals can reliably perceive a difference between a sample and its corresponding control, with 50% performance above chance. Wine is a complex matrix, and ODTs used in studies on wine can be based on inappropriate matrices and informal sensory methodologies. This post reports a study where the sensitivity of panelists to previously published ODTs for five compounds were tested. Results showed that, despite some limitations, this pragmatic approach may be useful when carrying out sensory studies with limited resources and within tight timelines, as it provides helpful information on panel members and detection thresholds for a specific matrix

Find out more

Autochthonous yeasts as a driver of innovation in the sparkling wine sector

By Vittorio Capozzi
Sparkling wines are effervescent ones, since they contain a relevant concentration of CO2, and may be produced by the traditional method also called méthode champenoise and charmat one. Both methods involve two fermentations steps. In the traditional method, secondary fermentation consists an in-bottle refermentation that occurs after the addition to the base wine of the so-called tirage solution (saccharose 20–25 g/l, Yeasts, grape must or wine, and bentonite). This step is followed by an aging period, during which sparkling wine matures and acquires the several intracellular compounds released by the yeast cells as excretion at the end of secondary fermentation, furthermore aging on lees led to yeast autolysis, both contributing to the development of the final aromas. For this reason, the final quality of the sparkling wines is affected by the yeast strain involved in wine production. In this post is summarized our work aimed to confirm the suitability of autochthonous Saccharomyces cerevisiae to improve the quality of regional sparkling wine. It was the first survey in our region to propose the selection of autochthonous starter cultures for sparkling wine including a preliminary tailored genotypic and technological screening, the performance in primary fermentation and the contribution during secondary fermentation in terms of volatile compounds. Find out more

wine summit: An open letter to Paddy Cosgrave

By Paula Silva
This is open letter to Paddy Cosgrave to thank him for the idea of wine summit. Science & Wine is a project of science communication regarding wine. This project started with the “Science & Wine: From the terroir to the glass” a one-day conference that occurred in Porto in 2017. Inspired in the conference success Science & Wine blog was born in 22 of January of 2018. Next year will start the Wine Science Cafés, which will be a great opportunity to engage in a two-way communication, where scientists can share new evidences, techniques, and applications but also will be aware of public expectations and concerns. In 2019 It will also the 1st Science & Wine World Congress will take place 8-10 May 2019 in Alfândega Congress Centre in Porto. It is my obligation, as researcher to communicate science and extension service is one of my major responsibilities. Find out more

Scientific impressions about the influence of alternative winemaking on wine chemical and sensory features

By Maurício Castilhos
Wine technology involves great numbers of chemical reactions during the two fermentative steps: alcoholic fermentation and malolactic fermentation. Grape pre-drying and submerged cap are examples of techniques applied by Brazilian wineries to study the reactions involving changes in wine polyphenols, which improve wine sensory quality. This post explains pre-dehydration and submerged cap techniques and explore their effects on the chemical and sensory profiles of the wines. Find out more

Pepper your wine with rotundone: yes, but until when?

By Olivier Geffroy
Rotundone is responsible for peppery aroma in wine that, above a certain concentration, is considered as a defect by some consumers. Viticulture and environmental features have a substantial impact on rotundone concentration in both grape berries and in finished wines. Cool and wet vintages promote the production of red wines with a higher rotundone concentration. Within a single vineyard, large spatial variability in rotundone associated with variation in the land underlying the vineyard and vine water status were reported. Patterns of this spatial variation are temporally stable from year to year. Find out more

Wine cooperatives as a vector of social entrepreneurship

By Mário Franco and Vitor Figueiredo
In many European countries and elsewhere in the world there is major renewed interest in cooperatives, as this type of business organisation seems to more resilient (and can achieve better performance than capitalist firms, principally at times of prolonged financial and economic crisis, such as the one experienced recently. The national and international wine market faces major challenges, either due to political and economic instability, or the great competition and decreasing world consumption of this type of drink. Therefore, wine cooperatives have been seen as representing sustainability in this sector in particular and present a certain impact on the society they are part of. Find out more

Wine and cardiovascular health: To drink or not to drink?

By Sohaib Haseeb, Bryce Alexander, Ricardo Lopez Santi, Adrian Baranchuk
Wine has been consumed for many years and is suggested to play an important role in the improvement of cardiovascular risk factors. Wine consumption has been inversely related with ischemic heart disease, and the alcohol-blood pressure association, in most studies, follows a J-shaped curve. These results have been attributed to the molecular constituents of wine, namely ethanol and polyphenols. Due to the continued interest in wine as a biological beverage, in this post the chemistry of wine as clinicians, including its chemical composition is reviewed. Biological effects of wine components and directions for future research are also explored. Find out more

Give artificial taste and olfactory intelligence for automatic wine analysis

By Lei Zhang
Electronic tongue (E-Tongue), as a novel taste analysis tool, shows a promising perspective for taste recognition. In this post, a voltammetric E-Tongue system is described. This E-Tongue was used to measure 13 different kinds of liquid samples, such as tea, wine, beverage, functional materials, etc.. The average recognition performance of 13 analytes achieves 98%. A number of research has fully confirmed that bionic E-Tongue can be used in industrial quality control, food quality analysis, etc. E-Tongue and E-Nose could be an optimistic start for revealing the biological taste and olfactory mechanism in the course of development of world artificial intelligence. Find out more

Synergistic effect of mixture of two proline-rich-protein salivary families (acidic and basic) on the interaction with wine flavanols

By Alba M. Ramos-Pineda, Ignacio García-Estévez, Montserrat Dueñas, M. Teresa Escribano-Bailón
This week post is about the interaction between salivary proteins and wine flavanols. In a recent study conducted by Alba María Ramos-Pineda and her group in Salamanca University, a synergic effect of the coexistence of two salivary-proline-rich proteins fractions (basic and acidic) on the interaction with flavanols were evaluated by HPLC-DAD, DLS and MALDI-TOF. It was observed a clear improvement of the interaction between (epi)catechin and proline-rich proteins when both types of proteins are blended. (epi)Catechins seem to bind preferentially basic proline-rich proteins, although the medium size aggregates flavanol-basic proline-rich proteins formed could favour the interaction with acidic ones giving rise to soluble mixed aggregates. Find out more

Inline to online: phenolics measurements made easy

By Jose Luis Aleixandre-Tudo
NIR spectroscopy could be an interesting approach to monitor the phenolic composition of grape berries transported on a conveyor belt system online. A contactless FT-NIR instrument can be used for on-line spectral data collection from grapes transported on a conveyor belt system. Spectral data can also be collected on static samples using the same NIR instrument. Spectral measurements of crushed berries captured from the conveyor belt system and the use of the homogenate extraction protocol as reference method provide the most accurate prediction models. Find out more

Norisoprenoids and aroma precursors in early-harvested grapes

By Maurizio Petrozziello, Andriani Asproudi and Alessandra Ferrandino
Climate change can influence winemakers to anticipate the harvest to limit alcohol content in wine and to provide satisfactory concentration of secondary metabolites in the grapes. This post describes a study carried out to understand the link between grape ripening, seasonal trend and wine aroma. Aromatic profile of Barbera and Pinot Noir wines, produced with early harvested grapes was assessed. Considering that norisoprenoids are important contributors to wine aroma, attention was focused on these compounds during both alcoholic fermentation and after three months of storage. At the end of fermentation, the highest β-damascenone content was detected in wines obtained from less ripe grapes, the content subsequently increased significantly after three months of storage; however, the levels of β-ionone decreased significantly during the same period. The reduction of wine alcohol as a result of harvesting earlier, especially for Barbera, was associated with optimal aromatic levels as well as good technological parameters. Find out more

Scale effect of viticultural zoning: effect of macro-terroir and basic terroir unit in Chianti Classico D.O.C.G. (Italy)

By Simone Priori
Terroir is a concept used to explain the specific combination and interaction of natural and human factors that affect distinctive wine characteristics. Soil and geology effects are sometimes considered considered less important than either climate or the human component. This post briefly describes a study carried out on one of the largest farms of the “Chianti Classico” wine district (Tuscany, Italy), focused on the effect of terroir on wine characteristics using two different zoning scales. At macro-terroir (MT), vineyards were carefully chosen based on lithology, soilscape, morphology, and mesoclimate. This study demonstrates that characteristics of pedo-geological landscapes can be used for a wine district zoning, while a more detailed soil mapping, leading to Unité Terroir de Base identification, is needed for differentiating wine characteristics. Find out more

Understanding the green character in red wines by a sensory-directed approach

By Sara Ferrero del Teso, María-Pilar Sáenz Navajas, Ignacio Arias Pérez, Purificación Fernández Zurbano, Ana Escudero, Vicente Ferreira
This post results from a study done with the aim of define the “green character” of red wines and characterise the groups of molecules potentially involved in that perception. Wines were screened by wine experts for different levels of green character. Phenolic fractions were obtained by liquid chromatography (LC) and further submitted to sensory and chemical characterisation. The volatile fraction was screened by semipreparative LC, gas chromatography-olfactometry (GC-O) and quantitative analysis. The green character was associated to vegetal aroma, astringency, green and dry tannins. No specific aroma compounds were identified in the GC-O evaluation of green wines, however the wines contained higher levels of fusel alcohols. The interaction between isoamyl alcohol and the anthocyanin-derivative fraction and/or tannins is suggested to be involved in the formation of green character in red wines. Find out more

Effect of Botrytis and Penicillium on quality of passito Amarone wine

By Barbara Simonato, Marilinda Lorenzini, Giacomo Zapparoli
This study analysed chemical composition and sensory properties of Amarone wines produced from withered grapes artificially contaminated by Botrytis cinerea and Penicillium spp. Changes in properties of the two wines were evident by comparing wines obtained from healthy grapes used as controls. Penicillium infection affects aroma and sensory profile with respect to wine produced from heathy and botrytized grapes. The differences observed between the two Penicillium wines suggest that the impact on Amarone wine quality may be potentially different depending on the contaminant species of withered grapes. Moreover, strain-species effects cannot be excluded, and it will be possible to assess them in further investigations. Find out more

Chemistry and photochemistry inspired by the colors of grapes and red wines

By Cristiane Copetti
Oxidative stress is caused by the insufficient capacity of biological systems to neutralize reactive species produced in excess. A serious imbalance between the generation of reactive oxygen species (ROS) and antioxidant (AOX) protection in favor of the former causes excessive oxidative damage in cells and tissues because the ROS excessive production is associated with disruption of cell cycle regulatory mechanisms. Results obtained suggest that wine is a potential antioxidant and have positive effect against reactive species generated in SH-SY5Y cells, suggesting a neuroprotective effect. Find out more

Metabolomics in the field, walking through the chemical diversity of grape

By Arnaud Lanoue
Polyphenols are grape compounds with numerous health benefit and organoleptic properties. These compounds act as key components of the plant defense system against diseases. Herein, are discussed the results of an innovator metabotyping (metabolite-phenotype characterization) study using different grape varieties. A field experiment was setting up with uniform pedo-climatic factors and viticultural practices of growing vines to favor the genetic determinism of polyphenol expression. Metabolite correlation network suggested that several polyphenol subclasses were differently controlled. In a near future, the present polyphenol metabotyping approach coupled to multivariate statistical analyses might assist grape selection programs to improve metabolites with health-benefit potential and plant defense traits Find out more

Chemistry and photochemistry inspired by the colors of grapes and red wines

By Frank H. Quina
Anthocyanins and pyranoanthocyanins are major contributors to the color of red wines. These pigments are cationic below about pH 3, highly colored, non-toxic, reasonably soluble in water or alcohol and stable to light. They exhibit good antioxidant or antiradical activity and, as part of our diet, confer several important health benefits. excited state proton transfer in uncomplexed anthocyanins or pyranoanthocyanins and ultra-rapid direct deactivation of the excited state in copigmented anthocyanins, contribute to make the color of anthocyanins and pyranoanthocyanins quite resistant to fading in sunlight. Find out more


My name is Paula Silva and I decided to accept this challenge of being the responsible editor of this blog because I believe that science must be shared and because it is very important to update public with information’s based in scientific evidences. My purpose is to serve people who wants to know more about wine by fostering networking, education, discussion, and exchange. I hope that this blog can be a resource on current and emerging issues in wine research area. Find out more