An approach to zoning in the wine growing regions of “Jerez-Xérès-Sherry” and “Manzanilla-Sanlúcar de Barrameda” (Cádiz, Spain)

The Appellations of Origin “Jerez-Xérès-Sherry” and “Manzanilla-Sanlúcar de Barrameda” occupy one of the oldest and most world renowned viticultural areas in the peninsula, but it is not exempt from the serious problems that are to be found throughout the sector. In order to try to adapt to the present situation, zoning plans are being promoted whereby priority is given to the quality of the product, sustainable development and the economic interests. This work undertakes an approach to the viticultural zoning. The nutritional state of the grapevines is studied by means of foliage analysis at veraison. The quality of production was measured by means of the berry weight and the analysis of the most usual variables of the must at the time of harvest (°Baumé, pH and titratable acidity) over five seasons, in the 21 plots where the soil profiles were opened for analysis. As a result of applying statistical analysis, the plots are grouped into five classes, two of which are subdivided. The most significant differences were established between the plots of class CL1, on Miocene limestone, and those of class CL5, on Pliocene-Quaternary sands and clays. Class CL1 presented the highest content of ash (mean ± sd CL1; CL5) (15.36 ± 1.73; 12.36 ± 1.77) and calcium (3.42 ± 0.90; 2.65 ± 0.72), the lowest berry weight (2.10 ± 0.30; 2.47 ± 0.50) and a greater Baumé degree (10.55 ± 0.86; 9.63 ± 0.98) than the CL5. This new approach takes other essential factors for the quality of the production into account such as the climate and the geomorphology (altitude, slope, and physiography)Las Denominaciones de Origen Jerez-Xérès-Sherry y Manzanilla-Sanlúcar de Barrameda ocupan una de las zonas de producción más antiguas de la península y de mayor reconocimiento a nivel mundial, aunque no están exentas de la grave problemática por la que atraviesa el sector. Para intentar adaptarse a la situación actual se están promoviendo planes de zonificación en donde prima la calidad del producto, el desarrollo sostenible y los intereses económicos. En este trabajo se realiza una aproximación a la zonificación vitícola. Para ello, se estudia el estado nutricional de las vides mediante el análisis foliar en el envero, la calidad de producción mediante el peso de los granos de uva y el análisis de las variables más usuales del mosto en la época de vendimia (°Baumé, pH y acidez total) durante 5 campañas, en 21 parcelas coincidentes con la apertura de los perfiles. Como resultado de aplicar el análisis estadístico, se han agrupado las parcelas en cinco clases, dos de ellas a su vez subdivididas. Las principales diferencias significativas se encontraron en las parcelas de las clases CL1, sobre albarizas del Mioceno, y las de la clase CL5, sobre arenas y arcillas del Plioceno-Cuaternario. La clase CL1 presenta el contenido más elevado de cenizas (mean ± sd CL1; CL5) (15,36 ± 1,73; 12,36 ± 1,77) y calcio (3,42 ± 0,90; 2,65 ± 0,72), el menor peso de grano de uva (2,10 ± 0,30; 2,47 ± 0,50) y un mayor grado Baumé (10,55 ± 0,86; 9,63 ± 0,98) que la CL5. Esta nueva aproximación tiene en cuenta otros factores esenciales para la calidad de la producción como son el clima y la geomorfología (altitud, pendiente, fisiografía

Comparison of CuO oxidation, analytical pyrolysis and IR spectroscopy to study the lignin signature in soil humic acids

2 pages, 1 figure, 4 references.-- Póster presentado al citado congreso en la Sesión II: Soil (S) Nº 496.-- Book of Abstracts of the Communications presented to the 26th International Meeting on Organic Geochemistry (IMOG), held in Costa Adeje, Tenerife – Spain, September 15 – 20, 2013.One of the most common methodologies in the study of lignins in soils is alkaline CuO oxidation [1]. This method allows quantification of the released lignin-derived phenols, however, it is time-consuming and requires previous derivatization before GC. In order to compare the information on lignin composition provided by current routine techniques used on soil humic acids (HA), this research compares molecular assemblages obtained from 16 HA samples by using either CuO degradation, or analytical pyrolysis (Py), as well as a nondestructive technique such as infrared (IR) spectroscopy.Peer reviewe

Exact relativistic models of thin disks around static black holes in a magnetic field

The exact superposition of a central static black hole with surrounding thin disk in presence of a magnetic field is investigated. We consider two models of disk, one of infinite extension based on a Kuzmin-Chazy-Curzon metric and other finite based on the first Morgan-Morgan disk. We also analyze a simple model of active galactic nuclei consisting of black hole, a Kuzmin-Chazy-Curzon disk and two rods representing jets, in presence of magnetic field. To explain the stability of the disks we consider the matter of the disk made of two pressureless streams of counterrotating charged particles (counterrotating model) moving along electrogeodesic. Using the Rayleigh criterion we derivate for circular orbits the stability conditions of the particles of the streams. The influence of the magnetic field on the matter properties of the disk and on its stability are also analyzed.Comment: 17 pages, 14 figures. arXiv admin note: text overlap with arXiv:gr-qc/0409109 by other author

Studies on the copigmentation between anthocyanins and flavan-3-ols and their influence in the colour expression of red wine

[ES] With the aim of evaluating the importance of the copigmentation process between anthocyanins and flavanols on the colour expression of red wine, assays were carried out in wine model systems with mixtures of compounds obtained from two Vitis vinifera grape varieties (Graciano and Tempranillo). Spectrophotometric and chromatic analyses were performed to evaluate the magnitude of the copigmentation and the modifications induced in the colour of the solutions. Measurement of the changes in the anthocyanin hydration constant (Kh) was also used to determine the strength of the copigmentation process. All the flavanols assayed induced significant changes in the colour, perceptible to the human eye, of the wine-like anthocyanin solutions at concentrations similar to those that can exist in red wines. The percentage contribution of the copigmentation with flavanols to the colour of the anthocyanin solutions was found to range from 2% to 20%. The extent of this effect was related not only to the concentration of flavanols but also to the qualitative composition of the flavanol preparations, as influenced by the part of the grape (either skin or seed) and the variety considered. Divergences were found between the evaluation of the copigmentation based on chromatic parameters in the CIELAB colour space and that based on the measurement at visible kmax, as the latter does not consider the integral colour changes produced in the visible spectrum. The results obtained confirmed the importance of the qualitative phenolic composition, determined in the wine by the type of grape and winemaking practices, to the production of an effective copigmentation process

Colour implications of self-association processes of wine anthocyanins

[EN] Copigmentation processes have been indicated to be crucial to stabilise coloured forms of the anthocyanins and explain colour expression in young red wines. Several studies exist about copigmentation between anthocyanins and different phenolics in model solutions, but little information is available about interactions among anthocyanins themselves. In this work, the process of self-association has been investigated in wine-like model solutions containing different grape anthocyanins (the 3-glucosides of malvidin, delphinidin and peonidin). The results obtained confirmed the existence of anthocyanin self-association and its influence on the apparent hydration constant of the anthocyanins with subsequent modification in the colour of the solutions. It was observed that the greater the degree of methoxylation of the anthocyanin B-ring the greater was the magnitude of the self-association. Colour analyses in the CIELAB space showed that self-association produces changes, which are more important in quantitative parameters (chroma, C ab* and lightness, L *) than in qualitative ones (hue, h ab). Self-association leads to an increase in C ab*, indicating a more intense colour of the solutions, and to a decrease in the psychometric index L *, meaning that a darkening is produced. The effects on the colour were more pronounced with the passage of time of storage of the solutions

Characterization of the Mean Degree of Polymerization of Proanthocyanidins in Red Wines Using Liquid Chromatography−Mass Spectrometry (LC-MS)

[EN] n HPLC-MS method for the characterization of proanthocyanidins (PA) has been refined. Further application to red wines provided interesting conclusions about the composition of the flavanol fraction and PA extractability during winemaking. The yield in PA extraction increases with the length of the postfermentative maceration (PFM), as well as the mean degree of polymerization (mDP) of wine flavanols. In early winemaking events mostly monomers to trimers are extracted from grape solids, whereas PFM is required for the significant extraction of higher oligomers. Nevertheless, at the end of a regular process of elaboration the mDP is not very high and does not usually exceed a value of 2.3, dimers and trimers being the predominant flavanols in red wines. With regard to groups of compounds, gallocatechins and prodelphinidins (located in the skins) are extracted rapidly in the first stages of the winemaking. On the contrary, long postfermentative macerations are required for the extraction of galloyled derivatives from the seeds. PA extractability is also dependent on the grape variety used for winemaking. Thus, wines made with Graciano grapes were found to require a longer process of PFM than those made from Tempranillo grapes to obtain similar yields in the extraction of flavanols