Wine books for holidays

By Paula Silva
The main post of last week was about wine aroma. Smelling wine is a complex experience, that goes beyond the olfactive sensation, is a journey that involve all the senses. It brings to our memory precise moments, specific colors, unique textures and amazing flavors. This is the kind of experience when you have a book in your hands. The smell of each page gives to the reader more than knowledge, gives an unforgettable experience. See here the 3 of the most remarkable books about wine. Good choices to learn about wine these holidays. Find out more

Modulation of wine astringency by mannoproteins –salivary protein/mannoprotein/polyphenol interactions

By Alba Ramos-Pineda, Ignacio García-Estévez, M. Teresa Escribano-Bailón

The oral sensation called astringency is commonly described as drying, roughing and puckering in the mouth epithelia. Since some polyphenols are able to bind salivary proteins, namely PRPs, they can form insoluble tannin-protein precipitates in the mouth, causing a loss of lubrication and increased friction in the oral cavity, which would explain its astringency. This mechanism is thought to be the main responsible of wine astringency. Results obtained indicate the existence of interactions between mannoproteins and flavonols but also between mannoproteins and salivary proteins, suggesting a possible formation of protein/polyphenol/polysaccharide ternary complex that probably affects the astringency perception.

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Characterization of the aroma profile of wines by solid-phase microextraction using polymeric ionic liquid sorbent coatings

By Leandro Wang Hantao
Aroma is one the main factors contributing to the quality of wine and sets the difference between a vast number of wines and wine styles produced throughout the world. The volatile organic compounds (VOCs) are a highly complex fraction of wine with more than 1.000 volatile compounds reported so far. Headspace solid-phase microextraction (HS-SPME) is a solvent less, equilibrium-based sample preparation technique that combines sampling and sample preparation into a single step, which may be performed relatively fast and under mild extraction conditions. HS-SPME is likely the ideal tool for aroma profiling of wines because it requires minimal sample handling and it bypasses the co-isolation of non-volatile organic compounds. Find out more

Does blind wine tasting work? Investigating the impact of training on blind tasting accuracy and wine preference

Qian Janice Wang and Domen Prešern
Blind wine tasting refers to the practice of tasting a wine without seeing the label, and deducing the grape variety, location of origin, and vintage of the wine based on what one perceives and infers from the glass. Earlier this year, as the Oxford University Blind Tasting Society started their training season, we had a unique opportunity to follow the progress of a group of relatively novice tasters as they went through the intensive five-week training program under the watchful eye of long-time coach and Oxford Companion to Wine contributor, Hanneke Wilson. The study, funded by an American Association of Wine Economists research scholarship, aimed to get a longitudinal view of expertise acquisition over an intense period of blind tasting training, where participants attend multiple tastings a week over a period of 36 days. Find out more

Purified grape pomace: a promising new wine fining agent

By Encarna Gómez-Plaza

Fining is a winemaking technique used to remove unwanted wine components that affect clarification, astringency, color, bitterness, aroma and even safety of the wine. Grape pomace could be a good alternative for protein-based fining agents in red wine, as they are insoluble, relatively inert, polysaccharide-based, and may also reduce turbidity problems and can be used to reduce tannins and contaminants. Moreover, their use would avoid allergen-related effects. Lastly, the use of pomace CW material as a fining agent could increase the added value of this byproduct, which is currently very low and very abundant in wineries.

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Lactic acid bacteria from Patagonian red wines

By Natalia S. Brizuela, E. Elizabeth Tymczyszyn and L. Semorile
Winemaking is a complex microbial process in which yeasts and lactic acid bacteria play a significant role. Yeasts consume sugars to produce ethanol and lead the alcoholic fermentation. The malolactic fermentation is responsible for the conversion of L-malic acid to L-lactic acid and CO2, causing a reduction of titrable acidity, and a small increase in the pH of wine. In order to avoid delay and spoilage during this process, the use of malolactic starter cultures is an option. However, the commercial cultures are formulated with strains from other wine-growing regions and their use could negatively affect the properties of wine terroir. The selection of autochthonous strains, best adapted to regional winemaking conditions, is desirable. Find out more

Climate change expandes the suitability for wine production to higher altitudes and to northern latitudes in Europe wine regions. Recent findings from the Life-ADVICLIM project

By Liviu Mihai Irimia, Hervé Quénol and Cristian Valeriu Patriche
Major shifts in climate suitability for the grapevine growing and wine production in all wine regions studied within the ADVICLIM project, regardless of their climate, and which predict shifts in the structure of winetype production in European viticulture. The potential for adaptation to climate change of some wine regions is larger while others is more limited, but the slow evolution of these shifts in time will enable the wine industry and consumers to become accustomed to a situation arising from a possible new climate context. Find out more

Indigenous wine colloids – a challenging analytical and functional chemistry for oenology

By Christian Coelho
Wine contains many types of colloidal substances, which must be considered by winemakers in their decisions related to wine production. Some of them, such as tannins and polysaccharides, are also known to contribute to the final sensorial perception of wines particularly regarding astringency, bitterness and smoothness. Indigenous colloids can be naturally extracted from grape and their concentration, after harvesting and pressing, are totally dependent of grape variety and maturity, and of pressing or the maceration pre-fermentative steps. Herein, I described the results of the impact of must clarification and the type of bottle closure during two consecutive vintages (2009 and 2010) on Chardonnay white wines organoleptic quality and chemical composition. Find out more

Artificial neural networks at the service of wine authenticity

By Juan Carlos Mejuto and Jesús Simal-Gándara
To implement the artificial neural network, various input variables are necessary, such as the year of harvest, the clarification technique used, its absorbance at different wavelengths, the concentration of anthocyanins, some physicochemical indices or sensory variables. It is important to highlight that it is not necessary to know relationships between variables; a multilayer perceptron (MLP) will establish a correlation between them, which is known as a universal approximation. In this way, knowing the values for the variables of a problem wine, the network allows us to calculate what the winemaking process has been. Artificial neural networks can be a valuable tool to evaluate the authenticity of the wine. In fact, neural networks are a portentous resource for multiple applications in the agro-food field. Find out more

The role of the wine bloggers in science

By Paula Silva
Blogs are an easy way to access a large amount of cutting-edge information with some expert analysis on emerging and controversial issues. Now, exist about 1000 of wine blogs with different purposes. Since there are no official guidelines or rules regarding what can be published, I decided to explore the importance of scientific knowledge in the professional life of a blogger. I want to thank to Amanda Barnes, Andrew Graham, Bjarne Mouridsen, Hugo Sousa Machado, Leeann Froese and Magnus Reuterdahl for accepting to answer my questions. Find out more

Wine metabolome

By Panagiotis Arapitsas

According to the International Organisation of Vine and Wine (OIV), wine is defined as the beverage resulting exclusively from the partial or complete alcoholic fermentation of fresh grapes. Lately, scientist started to use holistic/untargeted analytical approaches and try to follow the largest number of metabolites possible, without pre-define the metabolites of interest. Researchers working in this field known as metabolomics, are usually surprised in front of the richness of the wine metabolic fingerprint. In fact, between others, wine is a unique food/beverage because of its wide metabolic space coverage. Wine could be the richest food/beverage in term of number of metabolites. Find out more

Madeira wine: A chemical perspective of its unique aging process

By Vanda Pereira

Despite Madeira wine being produced more than 500 years ago and being a wine, which history is as rich as its complexity, there is still much to reveal.This fortified wine (17-22% ABV) is produced in Madeira, which is a Portuguese island near the coast of Morocco and holds a complex bouquet, with distinctive aromas of oxidation and aging, and a characteristic freshness due to its surprising acidity derived from the volcanic soils. It is produced from red (Tinta Negra) and white (Sercial, Verdelho, Boal, and Malvasia) grapes, from vines planted in small terraces and manually cultivated on the steep slopes of Madeira Island. Find out more

Animal models of disease and their applications and utility in wine research area

By Paula Silva
Animal models are very useful in wine research area. To work with these animal models, it is necessary to have cognitive ability, heart and courage. A researcher with these personality traits knows that there is no place in science for ill-designed, poorly executed, and inadequately reported studies of any type. Consideration of the welfare of animals in biomedical research comprises the ethical responsibility of the scientific community. The concept of Replacement, Reduction and Refinement as guiding principles for humane in vivo research is the best strategy to address this responsibility.Find out more

Professional highlights in wine area

By Paula Silva
Today ended the “Mostra da Universidade do Porto” that is an annual exhibition where the University of Porto schools promote their educational offer. The most repeated question made by high school students was “What can I do with that degree?”. I always answer, “All that you want”. I really believe it! Someone with cognitive and hard work capacities, can do anything with the tools acquire during the course. Joining creativity and courage, then are congregated the conditions to a brilliant career. Of course, that a personal career also depends in the networks that each one can establish. Let me exemplify what I mean within wine work area. Find out more

Analysis of high cited papers: Part II – Viticulture

By Paula Silva

For the release of my blog, at January 22, I wrote an article about high cited papers in the Food Science and Technology and Nutrition Dietetics research areas. Now, I decided to analyse what researchers studying viticulture are publishing. I performed a search, in Web of Science Core Collection, using “viticulture” as topic word. Then, I ordered the papers according with the number of citations in the period between January 2015 and February 2018. The analysis of the top ten list of the most cited papers (see below), show that researchers are concern about water deficit and its effect in viticulture and wine quality.

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ABOUT ME

My name is Paula Silva, I am an assistant professor in the Institute of Biomedical Sciences Abel Salazar (ICBAS) of University of Porto (UPorto) and I decided to have this blog to share my love by Science & Wine Find out more

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