Investigación
Publicaciones de vinos canarios
1. Juan J. Rodríguez-Bencomo; Héctor M. Cabrera-Valido; Juan P. Pérez-Trujillo; Juan Cacho. Bound aroma compounds of Gual and Listán blanco grape varieties and their influence in the elaborated wines. Food Chemistry. 127, pp. 1153 – 1162. 2011.
Abstract: Listán blanco and Gual are two white grape varieties grown in Spain (Canary Islands) and Gual is also grown in Portugal (Madeira Island). Wine quality could be improved by exploiting the varietal characteristics present in grapes as aroma precursors. At the present time, the enologic potential of these varieties has not yet been studied. Aroma precursors in musts and skins, and free volatiles in wines were determined in samples of both varieties. Aroma precursors of must and skins were isolated by absorption on XAD-2 resin and the aglycone liberated by means of acid hydrolysis. Free volatiles from wines and from aroma precursors were extracted with dichloromethane and then analysed by gas chromatography-mass spectrometry (GC–MS). Among the aroma precursors analysed, only α-terpineol, linalool and linalol oxides, 4-allyl-2,6-dimethoxyphenol, 2-methoxy-4-vinylphenol, 4-hydroxybenzaldehyde, vanillin and benzyl alcohol showed contents in grapes comparable to the levels observed in wine volatile compounds.
2. Juan J. Rodríguez-Bencomo; Héctor M. Cabrera-Valido; Juan P. Pérez-Trujillo; Juan Cacho. Bound aroma compounds of Marmajuelo and Malvasía grape varieties and their influence in the elaborated wines. European Food Research and Technology. 233, pp. 413 – 426. 2011.
Abstract: Marmajuelo and Malvasía are two white grape varieties grown in Spain (Canary Islands), the former only in the Canary Islands, while the latter is a variety widely spread throughout the world. At the present time, the oenological potential of these varieties grown in the Canaries has not yet been studied. Aroma precursors in musts and skins, and free volatiles in wines were determined in samples of both varieties. Aroma precursors of must and skins were isolated by absorption on XAD-2 resin, and the aglycone liberated by means of acid hydrolysis. Free volatiles from wines and from aroma precursors were extracted with dichloromethane and then analysed by GC–MS. The analysis of glycosidic aroma precursors showed that Malvasía variety presented higher contents of terpenes in grapes than those of Marmajuelo variety. In addition, some precursors of benzenic compounds presented higher contents in the musts of Malvasía with respect to those in the musts of Marmajuelo. The main difference in wine volatile composition was that cis-3-hexen-1-ol, ethyl acetate and γ-nonalactone compounds showed a significantly higher mean content in Malvasía wines than in Marmajuelo wines. Among the aroma precursors analysed, only α-terpineol, linalool oxides, 4-allyl-2,6-dimethoxyphenol, 2-methoxy-4-vinylphenol, 4-hydroxybenzaldehyde, vanillin and benzyl alcohol showed contents in grapes comparable to the levels observed in wine volatile compounds.
3. Juan Pedro Pérez-Trujillo; Zulimar Hernández; Francisco Javier López-Bellido and Isidro Hermosín-Gutiérrez. Characteristic Phenolic Composition of Single-Cultivar Red Wines of Canary Islands (Spain). Journal of Agricultural and Food Chemistry. 59, pp. 6150 – 6164. 2011.
Abstract: The detailed phenolic composition of five single-cultivar (Baboso Negro, Listán Negro, Negramoll, Tintilla, and Vijariego Negro) young and aged (vintages 2005_2009) red wines of the Canary Islands has been determined by HPLC-DAD-ESIMS”. Despite the total monomeric anthocyanin content decreasing for older wines in each set of single-cultivar wines, the corresponding anthocyanin profiles remained almost unchanged. Although all wine anthocyanin profiles were dominated by malvidin 3-glucoside, their differentiation by grape cultivar was possible, with the exception of Listán Negro. In contrast, the total content of non-anthocyanin phenolics did not appreciably change within vintages but polymerization, hydrolysis, and isomerization reactions greatly modified the phenolic profiles. Aglycone-type flavonol profiles offered the best results for differentiation of the wines according to grape cultivar (Listán Negro and Negramoll; Baboso Negro and Vijariego Negro; and Tintilla). Within flavan-3-ols, the β-ring trihydroxylated monomers ((-)-epigallocatechin and (-)-gallocatechin) and also (-)-epicatechin provided additional cultivar differentiation. Hydroxycinnamic acid derivatives and stilbene profiles were very heterogeneous with regard to both grape cultivar and vintage and did not significantly contribute to wine differentiation, even when structure-type profiles were obtained, with the exception of Tintilla, which always appeared as the most different single-cultivar wines. Finally, most Canary Islands wines showed characteristic high contents of stilbenes, especially trans-resveratrol.
4. Juan P. Pérez Trujillo; José E. Conde; María L. Pérez Pont; J. Câmara; José C. Marques. Content in metallic ions of wines from the Madeira and Azores archipelagos. Food Chemistry. 124, pp. 533 – 537. 2011.
Abstract: This study determines for the first time Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb contents in wines from the archipelagos of Madeira and Azores (Portugal). The greater part of the mean content for the different parameters fell within the ranges described in the literature, except for sodium whose higher content may be due to the effect of marine spray. ANOVA was used to establish the metals with significant differences in mean content between the wines from both archipelagos, between table and liquor wines of Madeira, and between wines of Pico and Terceira Islands from the Azores archipelago. Principal component analysis shows differences in the wines according to the wine-making process and/or the equipment employed. Stepwise linear discriminant analysis achieves a good classification and validation of wines according to the archipelago of origin, and the island in the case of Azores wines.
5. Pérez Trujillo, J.P.; Pérez Pont, M. L.; Conde González, J. E. Content of mineral ions in wines from Canary Islands (Spain). CyTA Journal of Food. 9(2), pp. 135 – 140. 2011.
Abstract: This study determines the content of Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb in wines from the islands of La Gomera and Fuerteventura in the Canarian archipelago (Spain). Analyses were performed by atomic spectroscopy techniques. Na, K, Ca and Mg were determined in dilute samples and the remainder of metals in samples previously treated with nitric acid in a microwave oven. The greater part of the mean content for the different parameters fell within the ranges described in the literature, except for sodium whose higher content may be due to the effect of marine spray. ANOVA was used to establish the metals with significant differences in mean content between type of wines, between both islands, and with the remaining islands of the Canarian archipelago. Principal component analysis shows that Fuerteventura wines can be differentiated from all other wines of the Canarian archipelago.
6. Juan Pedro Pérez Trujillo. Capítulo 14: Estudio de parámetros analíticos de la calidad de los vinos canarios con Denominación de Origen. Aportaciones al conocimiento del vino canario. Serie: Monografías nº LXXX. Sebastián Delgado Díaz (Ed).pp. 345 – 370. Tenerife Instituto de Estudios Canarios, 2010. ISBN 978-84-88366-87-0
Abstract: Sixteen conventional enological parameters, like that fluoride and major volatile compounds were determined in white, rose, red and sweet bottled wines with Denomination of Origin (DO) from the Canary islands in order to knowing their content and differences in basis to island or DO. The obtained results demonstrated that these wines represent a quality beverage without toxicological risks since the general content of all the components falls below the maximum concentration admissible. In the case of dry wines there are important differences according to type of wine and vintage, but not according to the geographical origin. In the case of sweet wines a complete differentiation between samples according to the island of production could be achieved only using two physicochemical parameters related to the elaboration process.
7. H. Cabrera Valido; J. J. Rodríguez Bencomo; S. J. Perez Olivero; J. E. Conde; J. P. Pérez Trujillo. Capítulo 15: Determinación de los parámetros de color en vinos tintos de las Islas Canarias. Aportaciones al conocimiento del vino canario. Serie: Monografías nº LXXX. Sebastián Delgado Díaz (Ed).pp. 371 – 380. Tenerife Instituto de Estudios Canarios, 2010. ISBN 978-84-88366-87-0
Abstract: Color parameters were determined in 68 red wines from Tenerife, La Palma and Lanzarote islands. Their visible spectra were recorded and chromatic coordinates, CIExy, CIELab and colorimetric Indexes were calculated. Statisticaly significant differences appeared among island and among denomination of origin. Lower intensity colors appeared in La Palma wines and higher intensities in North Tenerife wines.
8. Juan Pedro Pérez Trujillo. Capítulo 16: Estudio del contenido metálico en vinos canarios con Denominación de Origen.Aportaciones al conocimiento del vino canario. Serie: Monografías nº LXXX. Sebastián Delgado Díaz (Ed).pp. 381 – 413. Tenerife Instituto de Estudios Canarios, 2010. ISBN 978-84-88366-87-0
Abstract: The concentrations of 48 metals (major, minor, trace and rare earths) were determined in different types of wines belonging to different denominations of origin from the Canary Islands using several techniques of atomic spectroscopy. The obtained results were compared with those cited in the literature, and with the recommendations established by law or by the OIV. With the exception of sodium, most of the wines presented levels of the different metals within the normal intervals described in the literature. The differences between the various types of wines, islands and denominations of origin were studied. The more discriminant elements were established and techniques of multivariate analysis and neuralnetworks were applied to characterize wines according to their geographical origin.
9. S. J. Pérez Olivero; J. P. Pérez Trujillo. Capítulo 17: Determinación de compuestos volátiles en vinos monovarietales de Canarias. Aportaciones al conocimiento del vino canario. Serie: Monografías nº LXXX. Sebastián Delgado Díaz (Ed).pp. 415 – 427. Tenerife Instituto de Estudios Canarios, 2010. ISBN 978-84-88366-87-0
Abstract: Thirty six volatile compounds, sensorially important, belonging to three chemical families (lactones, short chaine fatty acids and carbonilic compounds) were quantified in white and red monovarietal wines of Canary Islands. The determinations were performed using the technique of gas chromatography with mass spectrometric detection coupled to solid phase microextracción (HS-SPME-GC-MS). γ-butyrolactone, acetic acid and acetoin were the major analytes. According to the chemical family there are several analytes that showed significant differences of the average content.
10. Juan José Rodríguez Bencomo; Juan Pedro Pérez Trujillo; Juan Cacho Palomar. Capítulo 18: Estudio del potencial aromático de diferentes variedades autóctonas de uva blanca de las Islas Canarias. Aportaciones al conocimiento del vino canario. Serie: Monografías nº LXXX. Sebastián Delgado Díaz (Ed).pp. 429 – 453. Tenerife Instituto de Estudios Canarios, 2010. ISBN 978-84-88366-87-0
Abstract: A study of the volatiles released by glycosidic aroma precursors isolated from the must of 4 grape varieties autochthonous from the Canary Islands (Listán blanco, Gual, Marmajuelo y Malvasía) was performed. The results have shown that Listán blanco and Gual present higher contents in terpenic and bencenic derivatives compounds, respectively. In addition, the analysis of the volatile compounds of the wines elaborated with these varieties has shown a higher floral-terpenic character in wines of Malvasía. Likewise, the influence of prefermentative «skin contact» in musts of Listán blanco variety and the volatiles of the wines were studied. Although differences of content in the aroma precursors between the different macerated musts were found, the same effect in the case of volatile compounds of wines was not found.
11. Héctor Manuel Cabrera Valido; Juan Pedro Pérez Trujillo; Juan F. Cacho Palomar. Capítulo 19: Estudio del aroma de los vinos y del potencial aromático de las variedades de uva tinta Listán negro, Negramol y Tintilla, y de uva blanca Verdello y Vijariego blanco, autóctonas de las Islas Canarias. Aportaciones al conocimiento del vino canario. Serie: Monografías nº LXXX. Sebastián Delgado Díaz (Ed).pp. 455 – 481. Tenerife. Instituto de Estudios Canarios, 2010. ISBN 978-84-88366-87-0
Abstract: A study of the volatiles released by glycosidic aroma precursors isolated from the must of the red grape varieties Tintilla, Negramoll and Listán negro, and the white grape varieties Vijariego blanco and Verdello, all of them autochthonous from the Canary Islands Also a study of the volatile compounds of the wines elaborated with these varieties was performed, putting emphasize on those with more sensorial interest.
12. Laura Culleré; Ana Escudero; Juan Pedro Pérez-Trujillo; Juan Cacho; Vicente Ferreira. 2-methyl-3-(methyldithio)-furan: A new odorant identified in different monovarietal red wines from Canary Islands and aromatic profile of these wines. Journal of Food Composition and Analysis. 21, pp. 708 – 715. 2008.
Abstract: The aroma of five monovarietal red wines from the Canary Islands, Spain (Negramoll, Listán negro, Tintilla, Vijariego negro, and Baboso negro) was studied by sensory analysis, quantitative gas chromatography-olfactometry (GC-O), and quantitative chemical analysis.
GC-O and multidimensional gas chromatography (MDGC) successfully identified in wine for the first time the potent aroma 2-methyl-3-(methyldithio)furan. We calculated the odour thresholds of this compound (<1ngL-1) and assessed it semiquantitatively in the study wines.
From the sensory point of view four descriptors (dried fruit, animal, toasty, and herbaceous) differed significantly between these varieties of wines. In GC-O, on extracts obtained by a dynamic headspace technique, significant differences were found in the intensity scores of β-damascenone, octanal, 2-methoxyphenol, ethyl cinnamate, ethyl 4-methylpentanoate, furfural, 2,3-pentadione, and 3-isopropyl-2-methoxypyrazine. Some of these compounds were detected as important odorants in only one varietal.
13. Juan J. Rodríguez-Bencomo; Juan J. Méndez-Siverio; Juan P. Pérez-Trujillo; Juan Cacho. Effect of skin contact on bound aroma and free volatiles of Listán blanco wine. Food Chemistry. 110 (1), pp. 214 – 225. 2008.
Abstract: Listán blanco is the major grape variety of the Canary Islands. Aroma precursors in musts and free volatiles in wines and their variations due to the skin contact process (10ºC and 0–12 h of maceration) were determined in samples of the Listán blanco grape variety. Aroma precursors of must were isolated by absorption on XAD-2 resin and the aglycone liberated by means of acid hydrolysis. Free volatiles from wines and from aroma precursors were extracted with dichloromethane and then analysed by GC-MS. The results of two consecutive vintages show that only aroma precursors of some terpenes and phenols may affect the final wine aroma. However, the majority of the free compounds of the wines did not present differences in content that could be related to the skin contact process.
14. H. Cabrera Valido; J.J. Rodríguez Bencomo; S. Pérez Oliveró; J.E. Conde; J.P. Pérez Trujillo. Parámetros de color de los vinos tintos de las Islas Canarias. Semana Vitivinícola. 3065, pp. 1462 – 1467. 2005.
Abstract: Se determinan los parárnetros CIELab e índices de color en vinos tintos de las Islas Canarias de dos añadas consecutivas. Se constata la existencia de diferencias significativas entre los valores medios de los diversos parámetros según el origen geográfico de los vinos.
15. Carlos Díaz; José Elías Conde; Daniel Estévez; Sergio Javier Pérez Olivero and Juan Pedro Pérez-Trujillo. Application of multivariate analysis and artificial neural networks for the differentiation of red wines from the Canary Islands according to the island of origin. J.Agric. Food Chem. 51(15), pp. 4303 – 4307. 2003.
Abstract: Eleven metals (K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb) were determined in 83 red wines from the Canary Islands. The wines presented a high concentration of Na and the concentrations of Cu and Zn were much lower than the maximum concentrations established by the International Office of Vine and Wine (OIV). Applying the principal component analysis, the dimension space was reduced to five principal components that explain 76.4% of the total variance and the wines tend to separate on the basis of the island of production. Linear discriminant analysis (LDA) allowed a reasonable classification of wines according to the island of production. When the artificial neural networks (Kohonen self-organising maps and back-propagation feed-forward as unsupervised and supervised techniques, respectively) were applied on the matrix of data constituted by the analysed metals, the results improved in relation to those obtained by other multivariate methods observing a differentiation of wines according to island of production.
16. C. Díaz Romero; S. Tort; E. Díaz and J. P. Pérez-Trujillo. Chemical characterization of bottled sweet wines from the Canary Islands (Spain). Acta Alimentaria. 32(3), pp. 247 – 256. 2003.
Abstract: Samples of sweet wines from the Canary Islands belonging to the Denominations of Origin of La Palma and Lanzarote islands were analysed in relation to chemical parameters. The main chemical parameters analysed demonstrated that these wines fulfil all the legal requirements since the content of all components tested falls below the maximum concentration admissible. Applying techniques of multivariate analysis (principal component, discriminant and cluster analysis), a complete differentiation could be achieved between the wines according to the island of production using only alcohol degree and isobutanol which are chemical parameters related with the elaboration process.
17. Juan Pedro Pérez Trujillo; Mireille Barbaste and Bernard Medina. Chemometric study of bottlede wines with denomination of origin from the Canary Islands (Spain) based on ultratrace elemental content determined by ICP-MS. Anal. Letters. 36 (3), pp. 679 – 697. 2003.
Abstract: This study determined the content in 39 trace and ultratrace elements, among them 16 rare earth elements, in 153 wines from the Canary Islands (Spain). Analyses were performed by ICP-MS. Rare earth elements were strongly correlated among one another, red wines mean contents in these elements being lower than those of white and rosé wines, and they are not suitable to classify wines according to the island of origin. Contrarily, good recognition and prediction abilities were achieved with the other 23 elements in both linear discriminant analysis (96.7 and 95.4%, respectively) and back-propagation artificial neural network (100 and 99.3%, respectively) to classify wines according to the island of origin. The most discriminant elements were established.
18. Sergio Frías; José Elías Conde; Juan J. Rodríguez Bencomo; Francisco García Montelongo and Juan Pedro Pérez-Trujillo. Classification of commercial wines from the Canary Islands (Spain) by chemometric techniques using metallic contents. Talanta. 59, pp. 335 – 344. 2003.
Abstract: Eleven elements, K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb, were determined in dry and sweet wines bearing the denominations of origin of El Hierro, La Palma and Lanzarote islands (Canary Islands, Spain). Analyses were performed by llame atomic absorption spectrophotometry, with the exceptions of lithium and rubidium for which llame atomic emission spectrophotometry was used. Sweet wines from La Palma were elaborated as naturally sweet with over-ripe grapes and significant differences were found in all the analysed elements with the exceptions of sodium, iron and rubidium with regard to dry wines from the same island. Contrarily, sweet wines from Lanzarote elaborated with grapes in a similar ripening state to dry wines did not present significant differences between them with the exception of strontium, the content of which was greater in dry wines. Among the three islands, significant differences in mean content were found with the exceptions of iron and copper. Cluster analysis and principal component analysis show differences in wines according to the island of origin and the ripening state of the grapes. Linear discriminant analysis using rubidium, sodium, manganese and strontium, the four most discriminant elements, gave 100% recognition ability and 95.6% prediction ability. The sensitivity and specificity obtained using soft independent modelling of class analogy (SIMCA) as a modelling multivariate technique were both 100% for El Hierro and Lanzarote, and 100 and 95%, respectively, for La Palma. The modelling and discriminant capacities of the different metals were al so studied.
19. Carlos Díaz; José Elías Conde; Daniel Estévez; Francisco García Montelongo; Juan Pedro Pérez Trujillo. Contenido mineral de los vinos tintos de Tenerife y Gran Canaria con Denominación de Origen. Viticultura y Enología Profesional. 87, pp. 30 – 36. 2003.
Abstract: The concentrations of K, Na, Li, Rb, Mg, Ca: Sr, Fe, Cu, Zn and Mn were determined in red wines with Denomination of Origin (DO) of Tenerife and Gran Canaria. The technlques used were flame atomic absorption and emission spectroscopy. With the exception of sodium, most of wines presented levels within the normal intervals described in the bibliography. The mean contents for all metals, with the exception of Rb and Zn, were higher in the wines from Gran Canaria than those observed in the wines from Tenerife. Applying Principal cornponent analysis wines tend to group according to the island of production, The ditterences of metallic content among the different denominations of origin of Ienerite island were not enough to reach a good classification among them. On the contrary, the denominations of origin from Gran Canaria were well differentiated according to the Na, Mg and Mn content.
20. Mireille Barbaste; Bernard Medina and Juan Pedro Pérez Trujillo. Analysis of arsenic, lead and cadmium in wines from the Canary Island, Spain, by ICP/MS. Food Additives and Contaminants. 20 (2), pp. 141 – 148. 2003.
Abstract: Because of their high toxicity, arsenic, lead and cadmium need to be quantified in food and beverages. For the first time, in this study, the content in arsenic, lead and cadmium was investigated in 152 wine samples from the Canary Islands belonging to 8 Denominations of Origin (DO) and four islands by inductively coupled plasma mass spectrometry (ICP-MS). The ranges of concentration found were 0.58-8.45 mg·L-1 for arsenic, 0.20-1.73mg·L-1 for cadmium and 3.89-159.5 mg·L-1 for lead, and the mean content was 3.13 mg·L-1, 0.63mg·L-1 and 28.74 mg·L-1, respectively. None of the analysed wines contained levels above the limits set by the International Office of Vine and Wine (O.I.V.), and thus did not pose a health hazard. Significant differences in mean content of those elements between harvest, type of wine, islands and DO were observed.
21. Ricardo López; Natalia Ortín; Juan-Pedro Pérez-Trujillo; Juan Cacho; Vicente Ferreira. Impact Odorants of Different Young White Wines from the Canary Islands. J. Agric. Food Chem.51, pp. 3419 – 3425. 2003.
Abstract: Five young monovarietal white wines from the Canary Islands made from Gual, Verdello, Marmajuelo, white Listán, and Malvasia grape cultivars were studied to determine the characteristics of their most important aromas and the differences among them. The study was carried out using gas chromatography-olfactometry (GC-O) to detect the potentially most important aroma compounds, which were then analyzed quantitatively by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. The strongest odorants in the GC-O experiments were similar in all cases, although significant differences in intensity between samples were noted. Calculation of the odor activity values (OAVs) showed that 3-mercaptohexyl acetate was the most active odorant in the Marmajuelo and Verdello wines, as were 3-methylbutyl acetate in the Gual wine, β-damascenone in the Malvasia wine, and ethyl octanoate in the white Listán wine. However, the most important differences between varieties were caused by the three mercaptans (3-mercaptohexyl acetate, 3-mercaptohexanol, and 4-methyl-4-mercapto-2-pentanone) and the vinylphenols (4-vinylphenol and 2-methoxy-4-vinylphenol). The correlation between the olfactometric values and the OAVs was satisfactory in the cases when the compound eluted in the GC-O system was well isolated from other odorants and had aromatic importance and the OAVs for the different wines were sufficiently different.
22. Sergio Frías; Carlos Díaz; José Elías Conde and Juan Pedro Pérez-Trujillo. Selenium and mercury concentrations in sweet and dry bottled wines from the Canary Islands (Spain). Food Additives and Contaminants. 20(3), pp. 237 240. 2003.
Abstract: The concentrations of selenium and mercury were determined by atomic absorption spectrophotometry in sweet and dry bottled wines from the Canary Islands, Spain. The concentrations of mercury ranged from 2.6 to 4.9 µg l-1 for sweet wines, and from 1.5 to 2.6 µg l-1 for dry wines, differences (p < 0.05) being observed according to the island of production and type of wine, but not with respect to vintage. The concentration of selenium varied between 1.0 and 2.0 µg l-1 for sweet wines, and between 0.6 and 1.6 µg l-1 for dry wines. Differences were found in the mean concentrations according to the type of wine. Dry wines produced in La Palma presented a higher (p < 0.05) mean content than those observed in the wines of El Hierro and Lanzarote.
23. Carlos Díaz; José Elías Conde; Juan J. Méndez and Juan Pedro Pérez-Trujillo. Volatile compounds of bottled wines with Denomination of Origin from the Canary Islands (Spain). Food Chem.81, pp. 447 – 452. 2003.
Abstract: The concentrations of the following major volatile compounds: ethanal, ethyl acetate, methanol, 1-propanol, 1-butanol, 2-butanol, isobutanol and amylic alcohols were determined by gas chromatography in 153 bottled wines with Denomination of Origin (DO) from the Canary Islands. The volatile compounds analysed were within the normal intervals described for each type of wines. The content of methanol was low and does not represent a toxicological risk for consumers. Isobutanol, methanol and total higher alcohols permitted a better differentiation of wines according to the type of wines. The island of production had more influence on the volatile profile than the DO within an island. Principal component analysis tend to separate red wines from the remainder of the wines and a differentiation of the red wines as a function of the vintage was observed.
24. Carlos Díaz; José Elías Conde; Carelia Claverie, Eugenio Díaz, Juan Pedro Pérez Trujillo. Conventional enological parameters of bottled wines from the Canary Islands (Spain). Journal of Food Composition and Analysis. 16(1), pp. 49 – 56. 2003.
Abstract: The following conventional enological parameters: pH, total acidity, malic and tartaric acids, volatile acidity, density, reducing sugars, sucrose, alcoholic degree, ash, ash alkalinity, free sulfur dioxide, total sulfur dioxide, total polyphenols index, anthocyans and tannins were determined in bottled wines from the Canary Islands in order to characterize them. Mostly the parameters analysed fell within the legislated intervals and within the normal intervals described in the literature. Important differences are observed among the mean values of analysed parameters in white, rosé and red wines. Polyphenolic parameters, alcoholic degree and reducing sugars were the parameters that best differentiated the wines according to the vintage.
25. M. Barbaste; B. Medina; L. Sarabia; M.C. Ortiz; J.P Pérez-Trujillo. Analysis and comparison of simca models for denominations of origin of wines from de Canary Islands (Spain) builds by means of their trace and ultratrace metals content. Anal. Chim. Acta. 472, pp. 161 – 174. 2002.
Abstract: Various models have been constructed and analysed for eight denominations of origin of wines bottled in the Canary Islands, using their content in different metals, with the Soft Independent Modelling Class Analogy (SIMCA) technique. The metals were grouped in three blocks: “rare earths”, “lead isotope ratios” and “other metals”. The model constructed with all the variables was taken as the reference model. This model has adequate sensibility and specificity. The contribution of each element to the model of each denomination of origin (DOs), as well as their capacity to discriminate between the DOs is shown. Cluster analysis, using the Ward method, of the SIMCA distances between the different DOs reveals the similarity of the different denominations of origin. Using only the rare earths or the lead isotope ratios it is not possible to construct adequate models for the different DOs given the lowspecificity obtained. The models constructed with the other metals, alone or combined with the lead isotope ratios, gave similar results to those obtained using all the variables. Finally, the similarity of the models was analysed by a weighted distance between the sensibilities and specificities of each of them compared with the rest. Cluster analysis using the Ward method shows the models which are similar as to their sensibility and specificity. The innovative aspect of the work lies in the use of cluster analysis to demonstrate the similarity between the SIMCA boxes of a model, and the definition of the distance between models based on the sensibility and specificity for the eight DOs with the five groups of variables considered.
26. J.E. Conde; D. Estévez; J.J. Rodríguez Bencomo; F.J. García Montelongo and J.P. Pérez-Trujillo. Characterization of bottled wines of Tenerife island (Spain) by their metallic content. Italian Journal of Food Science. 14(4), pp. 375 387. 2002.
Abstract: K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb concentrations were determined in bottled wines from the Tenerife Island belonging to the denominations of origin of Abona, Valle de Güímar, Valle de La Orotava, Tacoronte-Acentejo and Ycoden-Daute-Isora in order to characterize them. Analyses were performed by flame atomic absorption spectrophotometry with the exception of Li and Rb for which flame atomic emission spectrophotometry was used. The greater part of the mean content for the different parameters (K=688 mg/L, Ca=64.3 mg/L, Mg=83.8 mg/L, Fe=2.25 mg/L, Cu=0.24 mg/L, Zn=0.68 mg/L, Mn=1.09 mg/L, Sr=0.54 mg/L, Rb=1.94 mg/L, Li=6.39 mg/L) fell within the ranges described in the literature, except for sodium (88 mg/L) whose higher content may be due to the effect of marine spray. For copper and zinc most samples were below the maximum amount recommended for these elements by the OIV. Differences in mean content according to vintage, type of wine and denomination of origin were determined for the different metals. Principal Component Analysis grouped wines according to their type and denomination of origin. Stepwise linear discriminant analysis gave about 80 % correct classification of samples according to their denomination of origin.
27. Carlos Díaz; José Elías Conde; Juan Jesús Méndez; Juan Pedro Pérez Trujillo. Chemometric studies of bottled wines with denomination of origin from the Canary Islands (Spain). Eur. Food Research Technol.215, pp. 83 – 90. 2002.
Abstract: Seventeen physicochemical parameters including conventional enological parameters, polyphenolic parameters and volatile compounds were determined in 153 wines from the main wine producers belonging to the Canarian zones with Denomination of Origin. Numerous significant correlations were found between the physicochemical parameters analysed. Applying the principal component analysis, the wines tend to separate on basis of the type of wine. Besides, the dimension space was reduced to six principal components that explain 76.1% of the total variance. The principal components analysis of the red wines separated them as a function of vintage. Linear discriminant analysis (LDA) applied to all the wines allowed a reasonable differentiation according to vintage, type of wine and island of production.
28. Juan Pedro Pérez Trujillo; Mireille Barbaste and Bernard Medina. Content in trace and ultratrace elements in wines from the Canary Islands (Spain) determined by ICP-MS. J. Wine Research. 13(3), pp. 243 – 256. 2002.
Abstract: One hundred and fifty-three white, rosé and red wine samples from the Canary Islands (Spain) were analysed. The wines were sampled from two different vintages, eight denominations of origin, and four islands. The concentration of twenty trace and ultratrace elements was measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Differences in element concentrations depending on vintage, type of wine (white, rosé, red), and region of origin were observed.
29. Sergio Frías; J.E. Conde; M.A. Rodríguez; V. Dohnal and J.P. Pérez Trujillo. Metallic content of wines from the Canary Islands (Spain). Application of artificial neural networks to the data analysis. Nahrung/Food. 46 (5), pp. 370 – 375. 2002.
Abstract: Eleven elements, K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb were determined in dry and sweet wines bearing the denominations of origin of El Hierro, La Palma and Lanzarote islands (Canary Islands, Spain). Analyses were performed by flame atomic absorption spectrophotometry, with the exceptions of Li and Rb for which flame atomic emission spectrophotometry was used. The content in copper and iron did not present risks of casses. All samples presented a copper and zinc content below the maximum amount recommended by the Office International de la Vigne et du Vin (OIV) for these elements. Significant differences in the metallic content were found among the different islands. Thus, Lanzarote presented the highest mean content in sodium and lithium and the lowest mean content in rubidium, and La Palma presented the highest mean content in strontium and rubidium. Sweet wines from La Palma, elaborated as naturally sweet with over-ripe grapes, presented mean contents significantly higher with regard to dry wines from the same island in the majority of the analysed elements. Cluster analysis and Kohonen self-organising maps showed differences in wines according to the island of origin and the ripening state of the grapes. Back-propagation artificial neural networks showed better prediction ability than stepwise linear discriminant analysis.
30. Miguel-Angel Rodríguez; Guillermo González; José-Elías Conde and Juan-Pedro Pérez. Principal component analysis of the polyphenol content in young red wines. Food Chemistry. 78, pp. 523 – 532. 2002.
Abstract: In the present study the content of 15 polyphenols was determined in 55 samples of red wines from different denominations of origin in the Canary Islands (Spain) using high performance liquid chromatography (HPLC) with UV and fluorescence detection. The most important differences in content among wines according to different categories (island, zone and denomination of origin) were established. In general, red wines from the Canary Islands had a content in polyphenols in the lower part of the range considered normal. The exception was quercetin, with a mean content (17.5 mg/l) higher than in other wines, which may be a peculiarity of these particular wines. The principal component analysis (PCA) technique was used to study the latent structure. A good differentiation among wines according to their production area was obtained using linear discriminant analysis (LDA).
31- Carlos Díaz; José Elías Conde; Carelia Claverie, Eugenio Díaz y Juan Pedro Pérez Trujillo. Parámetros enológicos de vinos de las Islas Canarias de acuerdo con su origen geográfico. Alimentaria. 334, pp. 147 – 150. 2002.
Abstract: The following conventional enological parameters: pH, total acidity, malic and tartaric acids, volatile acidity, density, reducing sugars, sucrose, alcoholic degree, ash, ash alkalinity, free sulfur dioxide, total sulfur dioxide, total polyphenols index, anthocyans and tannins were determined in bottled wines with Denomination of Origin (DO) from the Canary islands in order to find out differences in basis to the island or DO of production. Mostly the parameters analysed fell within the legislated intervals and within the normal intervals described. While there are important differences according to type of wine and vintage, the low differences according to the geogrphical origin were found.
32. S. Frías; J.P. Pérez Trujillo; E.M. Peña; J.E. Conde. Classification and differentiation of bottled sweet wines of Canary Islands (Spain) by their metallic content. Eur. Food Research Technol. 213(2), pp. 145 – 149. 2001.
Abstract: This study determines Na, K, Ca, Mg, Fe and Cu contents in sweet wines bearing the denominations of origin of Lanzarote and La Palma islands (Canary Islands, Spain) from two consecutive harvests. Analyses were performed by flame atomic absorption spectrophotometry: Na, K, Ca and Mg were determined in dilute samples and Fe and Cu in samples previously treated with nitric acid in a microwave oven. The denomination of origin of La Palma island has a high content in K, Ca, Mg and Fe, while the denomination of origin of Lanzarote has a high Na and Cu content. ANOVA shows significative difference in content between these two islands for Na, K, Ca and Mg, Na and Mg being the highest. Principal component analysis and cluster analysis show differences in the wines according to their geographical origin. Linear discriminant analysis shows a classification of 100 % of wines in their categories. The best discriminant metals are Na and Mg, a geographical differentiation also being possible with these two metals only. Likewise, a joint study is made with the sweet wines of the denomination of origin of Malaga, it being possible to differentiate between Canarian and Malaga wines by using the content in Mg only. Again, separation of Lanzarote, La Palma and Malaga was achieved only with Na and Mg metals.
33. S. Malanova; F.J. García Montelongo; J.P. Pérez Trujillo; M.A. Rodríguez-Delgado. Optimisation of sample preparation for the determination of trans-resveratrol and other poliphenolic compounds in wines by high performance liquid chromatography. Anal. Chim. Acta. 428, pp. 245 – 253. 2001.
Abstract: Different methods for sample preparation as a prelirninary stage for the simultaneous deterrnination of trans-resveratrol and other polyphenolic compounds are compared with the aim to establish the best conditions for the deterrnination of these compounds in wine samples by high performance liquid chromatography (HPLC). Sample preparation using liquid-liquid extraction and solid-phase extraction were compared. Liquid-liquid extraction using as organic solvent diethyl ether at pH 2.0 shows the best results. The dried extract was solved in methanol/water 1: 1 (v/v) that improve drastically the separation efficiency. The developed method was applied to the analysis of wines from the Canary Islands.
34. M.A. Rodríguez Delgado; G. González; J.P. Pérez Trujillo and F. García Montelongo. Trans-resveratrol in wines from the Canary Islands (Spain). Analysis by high performance liquid chromatography. Food Chem.76, pp. 371 375. 2001.
Abstract: Trans-resveratrol is a phytoalexin from grapes with interesting therapeutic properties. Thus considerable interest has been directed to its study. In this paper the determination of trans-resveratrol in wines from the Canary Islands by high performance liquid chromatography (HPLC) using absorbance and fluorescence detectors in series is reported. The use of fluorimetic detection improves selectivity and sensitivity for the determination of this compound. The detection limits in real samples were 0.02 mg/l and 0.003 mg/l for absorbance and fluorescence detection, respectively. We compared the results obtained by means of both detectors for 58 red wines from different denominations of origin and no significant differences were observed either between both methods or among the denominations of origin. The mean level found in bottled red wines was 2.89 mg/l.
35. O.B. Martínez; C. Díaz; T.M. Borges; E. Díaz; J.P. Pérez Trujillo. Concentrations of fluoride in wines from the Canary Islands. Food Additives and Contaminants. 15(8), pp. 893 – 897. 1998.
Abstract: Potentiometry using an ion-selective electrode has widely been used for determining fluoride because of its simplicity and rapidity. The concentration of fluoride was determined (Gran’s method) in 70 wines from the main wine-producing regions of the Canary Islands. The mean concentration of fluoride in wines from a region with a high concentration of fluoride in drinking waters was significantly (p < 0.05) higher than those mean concentrations obtained in the remaining wines. Non-important differences were found among the types of wine analysed. However, the fiuoride concentrations of all the Canarian wines analysed here did not present a risk for the public health.