Extraction of Some Ellagic Tannins and Ellagic Acid from Oak Wood Chips (Quercus pyrenaica L.) in Model Wine Solutions: Effect of Time, pH, Temperature and Alcoholic Content

The subject of the present work is the study of the influence of pH, temperature, alcoholic content and time on the extraction of some individual ellagic tannins (castalagin, vescalagin, grandinin, roburin D and E) and ellagic acid from oak wood chips (Quercus pyrenaica L.) within model wine solutions. The determination of these compounds by reversed-phase high-performance liquid chromatography (HPLC), after 104 extraction days, enabled us to establish the qualitative and quantitative evolution of each component and the effect of each extraction condition on individual and total ellagic tannins from oak wood chips. Vescalagin and castalagin were the most abundant individual ellagic tannins measured under all extraction conditions. Individual ellagic tannins and ellagic acid increased during the first weeks of extraction, followed by a decrease. Under the extraction conditions examined, temperature was the main factor influencing ellagic tannins and elagic acid evolution. The results suggest that a decrease/degradation of these compounds is less noticeable at low temperatures (12ºC). After 104 extraction days the ellagic tannins content in a model wine solution at 12ºC was higher than the content of ellagic tannins in solutions at 20ºC. On the other hand, the effects of alcoholic content and pH of model wine solutions on the extraction and evolution of the analysed compounds (except for castalagin and vescalagin) seemed to be less important than temperature

Validation and Comparison of Formol and FT-IR Methods for Assimilable Nitrogen in Vine Grapes

In this study, two methods used to evaluate assimilable nitrogen in grape juice were compared, namely:the formol method and the Fοurier-transform mid-infrared (FT-MIR) spectroscopy. At the outset theformol method was validated in the laboratory by determining parameters such as precision, accuracyand trueness. Parallel recovery studies were conducted with a model solution and natural grape juice forammonium and arginine. Average recoveries of ammonium for the formol titration ranged from 77%to 88% and for arginine from 90% to 97%. The repeatability and the intra laboratory reproducibilitywere ±6.4 and ±31.7 (mg/L of nitrogen) respectively. Formol titration was used as the reference methodfor the calibration of FT-MIR spectroscopy to determine the assimilable nitrogen in grape juice. Grapejuice samples (n=71) for 7 red and 7 white varieties from the Lisbon region in Portugal were analyzedsimultaneously by using the formol method and Fοurier-transform mid-infrared (FT-MIR) spectroscopy.The results of this study demonstrated that it is possible to explore the applicability of FT-ÎœIR technologyto detect the assimilable nitrogen in grape juice for quantification purposes. The correlation coefficient(R2=0. 993), standard prediction error (SEP; 6.4 mg/L) and the RPD or standard deviation of the data/standard error of prediction value (Sd/Se; 7.8) proved satisfactory for the calibration of the instrument.In addition, the results obtained by FT-MIR spectroscopy were comparable to those obtained when usingthe reference method

Effects of Abiotic Factors on Phenolic Compounds in the Grape Berry – A Review

Grape berry phenolic compounds are widely described in literature. Phenolics can be divided into two main groups: flavonoids and non-flavonoids, of which the flavonoids are the most important. The two bestknown groups of flavonoids are the anthocyanins and condensed tannins (also called proanthocyanidins).  Anthocyanins are responsible for the red colour in grapes. The condensed tannins (proanthocyanidins) are responsible for some major wine sensorial properties (astringency, browning, and turbidity) and areinvolved in the wine ageing processes. This review summarises flavonoid synthesis in the grape berry and the impact of environmental factors on the accumulation rate during ripening of each of the flavonoids.  The impact of the accumulated flavonoids in grapes and the resulting impact on the sensorial aspects of the wine are also discussed

Influence of Fining and Tartaric Stabilisation Procedures on White Wine Mannoprotein Content

Limpidity is a major quality attribute in white wine appreciation. After alcoholic fermentation and ageing,white wines are normally subjected to protein and tartaric stabilisation, followed by filtration. The impactof bentonite and gelatine fining and cold static tartaric stabilisation on the mannoprotein content of twowhite wines was studied. All treatments promoted a decrease in the content of mannoproteins. Bentonitefining largely affected the mannoproteins with the highest molecular weight, as did cold static tartaricstabilisation and gelatine fining

Brand marks examination. Empirical study of graphic parts in their relation to contrast, recognition, and memorization

Brand Visual Identity is an identification system that, with flexibility, ensures the unity and coherence of visual communication (in multiple media: physical as products, objects, or graphics; architectural and ambiance; audio-visual; digital and virtual). Brand Marks occupy a top place in the good performance of most Brand Visual Identity systems, even when these rely more on imagery and use Brand Marks with less expressiveness. In dynamic Visual Identity systems, the Brand Marks may constitute themselves as systems within the Brand Visual Identity supersystem. This study aims to dissect existing brand marks, focusing on how the graphic components (symbol, logotype) are designed, prioritised, and correlated to achieve differentiation, contrast, recognition, and memorisation. This include an empirical examination based on direct observation and exploration and in survey by questionnaire with a sample of 400 participants, aiming at the definition of design principles to aid the design of Brand Marks and to be considered in the definition of the “map of competitors” tool, which intends to aid in the analysis of multiple visual identities competing in the same market or segment.info:eu-repo/semantics/publishedVersio

Chemical and Sensorial Characterization of Tropical Syrah Wines Produced at Different Altitudes in Northeast of Brazil

Over the years, viticulture has expanded to new regions outside the temperate zones, such as Northeast Brazil, India, Thailand, Myanmar, Vietnam, Bangladesh and Venezuela, characterized by the production of tropical wines. It is important for the productive sector to comprehend the effects of grapevine interaction with the characteristics of each new region on wines composition. In this study, the composition of wines of Syrah from two regions with different altitudes in Northeast Brazil were analyzed by different methodologies to characterize chemical compounds as sugar, acids, minerals, phenolics (anthocyanins, flavonols, stilbenes and condensed tannins) and the sensory profile. The wines of the Bahia region (1100 m of altitude) obtained high concentrations for chemical parameters related to color, monomeric anthocyanins, stilbenes and monomeric and oligomeric tannins. Wines of the low altitude region, Pernambuco (350 m of altitude) were characterized by higher concentrations of flavonols (kaempferol, isorhamnetin, quercetin and rutin) and polymerized tannins. The chemical composition of wines from the two studied regions was influenced by altitude. A trend towards higher concentrations in most for phenolic compounds analyzed was observed in wines from the higher altitude region during the two years of study. Regarding the sensory profile, fruity, floral, herbaceous and empyreumatic attributes aromatic obtained highest scores in wines of the 350 m altitude region, the other attributes were dependent on the year of harvest

Barrel-to-barrel variation of phenolic and mineral composition of red wine

The aim of the present work was to evaluate the effect of barrel-to-barrel variability on chemical characteristics of red wine. An experimental trial was carried out involving two red wines from the Portuguese DO Dão and independent replicates of French oak barrels (Quercus sessiliflora Salisb.) from three different cooperages. After six months of aging, comprehensive chemical characterization of the wines took place: general physical-chemical analysis by FTIR, phenolic composition and chromatic characteristics, major mineral elements (K, Mg, Ca, Na, and Fe) by flame atomic absorption spectrometry (FAAS), minor and trace elements (Li, Be, Ti, Mn, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Cs, Ba, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Tl, Pb, and U) by inductively coupled plasma mass spectrometry (ICP-MS). In respect to barrel effect, significant differences between replicates were observed for phenolic composition, especially polymerized pigments, flavonoids and color intensity. Regarding major, minor and trace elements, no significant differences were observed between barrel replicates with exception of iron and copper

Resposta da casta ‘Syrah’ à monda de cachos

Este trabalho teve por objectivo estudar o efeito da monda de cachos na produção e nas características analíticas das uvas e do vinho, casta ’Syrah’, bem como analisar a vertente económica da operação. Num ensaio realizado no ano de 2007 na região vitícola de Alenquer, Quinta do Pinto, Merceana, comparou-se uma modalidade testemunha não mondada (T) com duas modalidades mondadas, em dois estados fenológicos distintos, bago de ervilha (MBE) e pintor (MP), ambas com a mesma intensidade de monda (50% de cachos removidos). A monda induziu uma redução significativa no rendimento (-36%) e uma melhoria nos parâmetros da qualidade, excepto na acidez total e na tonalidade da cor que apresentaram valores idênticos aos da testemunha não mondada. Destaca-se o efeito positivo da monda no grau alcoólico e nos compostos fenólicos, principalmente nas antocianinas. Os vinhos elaborados a partir das uvas das modalidades mondadas foram significativamente melhor classificados e preferidos em prova organoléptica. O vigor e expressão vegetativa da videira não foram significativamente influenciados pela monda. O efeito da época de monda não foi significativo em qualquer dos parâmetros analisados. A monda aumentou os custos de produção, principalmente quando realizada ao bago de ervilha, sendo uma opção viável em vinhas com produções potenciais elevadas, quando o objectivo é a produção de vinhos de qualidadeinfo:eu-repo/semantics/publishedVersio

Small Fermi energy and phonon anharmonicity in MgB_2 and related compounds

The remarkable anharmonicity of the E_{2g} phonon in MgB_2 has been suggested in literature to play a primary role in its superconducting pairing. We investigate, by means of LDA calculations, the microscopic origin of such an anharmonicity in MgB_2, AlB_2, and in hole-doped graphite. We find that the anharmonic character of the E_{2g} phonon is essentially driven by the small Fermi energy of the sigma holes. We present a simple analytic model which allows us to understand in microscopic terms the role of the small Fermi energy and of the electronic structure. The relation between anharmonicity and nonadiabaticity is pointed out and discussed in relation to various materials.Comment: 5 pages, 2 figures replaced with final version, accepted on Physical Review