Página 1 dos resultados de 52 itens digitais encontrados em 0.001 segundos

Effect of the estufagem process on the chemical constituents of Madeira wines

Pereira, Vanda Nulita Gomes
Fonte: Universidade da Madeira Publicador: Universidade da Madeira
Tipo: Tese de Doutorado
Publicado em 28/03/2014 ENG
Relevância na Pesquisa
56.83%
Madeira wine is a product of well-established reputation, whose aroma and flavour is the result of unique combinations. Particularly, its maturation may include estufagem, wherein wine is usually heated at 45 °C for three months. During this period, several chemical changes may occur, so it is essential to assess its impact on the wine. In this sense, the main objective of the thesis was to evaluate the effect estufagem on the chemical constituents of Madeira wine, specifically on those molecules potentially important in the development of its typical features. Firstly, analytical methodologies capable of determining the target compounds, combining precision and reproducibility to execution effectiveness, were developed. Then various monovarietal Madeira wines were analysed during estufagem under standard and overheating conditions in order to assess its effect. The following compounds were evaluated: furans, amino acids, biogenic amines, polyphenols, organic acids and volatile compounds. In addition, the total polyphenolic composition, the antioxidant potential and the colour of these wines were also evaluated. The results show that most constituents change due to the heating process. Particularly, the heating promotes the development of 5-hydroxymethylfurfural (HMF) in sweet wines submitted to estufagem at higher temperatures. Moreover...

Evolution of ethyl carbamate during Madeira wine ageing by GC-MS: a new methodology

Leça, João Micael da Silva
Fonte: Universidade da Madeira Publicador: Universidade da Madeira
Tipo: Dissertação de Mestrado
Publicado em /11/2014 ENG
Relevância na Pesquisa
56.47%
Recently, ethyl carbamate (EC) was reclassified by the International Agency for Research on Cancer (IARC) as "probably carcinogenic to humans" and occurs mainly in fermented beverages. Nowadays many countries have set limit values for EC in alcoholic beverages. In this sense and taking into account the low concentrations found in alcoholic beverages, the scientific community has shown interest for the development of new analytical methods, whereby its simplification plays an important role in the EC control and prevention. Firstly, a simple, rapid and sensitive methodology was developed for the EC quantification in fortified wines by microextraction by packed sorbent (MEPS) with gas chromatography coupled with a mass spectrometer detector (GC-MS). This method showed good linearity (R2 = 0.999) and sensitivity (LOD = 1.5 μg/L). The accuracy of the method was assessed by means of repeatability and reproducibility (RSD < 7%). Moreover, a good recovery has been demonstrated (97 – 106%) as well as its applicability (16 fortified wines). Thus, the developed methodology has proven to be an excellent approach for routine quantification of EC in fortified wines. The EC evolution was also evaluated during a year and half of Madeira wine ageing submitted to two traditional ageing methods...

Identification of key odorants on madeira wine, their impact on typicity and elucidation about formation mechanisms

Ferreira, A. C. Silva; Silva, H. Oliveira e; Machado, B. P.; Marques, C.; Albuquerque, F.; Camara, J.; Hogg, T.; Pinho, P. Guedes de
Fonte: Universidade Católica Portuguesa Publicador: Universidade Católica Portuguesa
Tipo: Artigo de Revista Científica
Publicado em //2008 ENG
Relevância na Pesquisa
46.38%

Estratégias para a redução de carbamato de etilo em vinhos Madeira

Martins, Cátia Sofia Faria
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
36.9%
O carbamato de etilo (EC) é um composto potencialmente tóxico, que foi reclassificado em 2007 como um composto provavelmente carcinogénico para humanos (grupo 2A) pela Agência Internacional de Pesquisa contra o Cancro (IARC). Este composto tem sido detectado em diversos alimentos fermentados e bebidas alcoólicas, nomeadamente em vinhos Madeira. Este trabalho visa definir estratégias conducentes à redução de EC em vinhos Madeira. Assim, foram estudados alguns factores intrínsecos (casta, tipo de vinho e processo) e extrínsecos (luz, a temperatura e o tempo de armazenamento) ao vinho que condicionam a formação de EC. Paralelamente, foi estabelecido o perfil em ácidos orgânicos voláteis com vista a explicar o aumento de acidez observada durante o envelhecimento dos vinhos Madeira. A microextracção em fase sólida em modo espaço de cabeça combinada com a cromatografia compreensiva bidimensional em fase gasosa acoplada à espectrometria de massa por tempo de voo (HS-SPME/GC × GC–ToFMS) foi a metodologia utilizada nestes estudos. Os vários ensaios foram realizados em vinhos modelo sintéticos e em vinhos Madeira. Este estudo permitiu concluir que a casta e o tipo de vinho (dois factores intrinsecamente associados)...

“Tourist Madeira Wine Perception: A Structural Equation Modeling Approach”

Sampaio, Ana
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Aula
ENG
Relevância na Pesquisa
56.94%
The field of wine tourism is emerging at international level as a new product with significant economic potentialities and characteristics that may locate it in the paradigm of sustainable development. This paper analyzes a specific wine tourism segment, Madeira Wine tourism, in the global context of tourist consumer behavior, through perception‟s examination of wineries‟ visitors. Specifically, it is investigated the indirect influence of destination image construct on global tourist satisfaction with the travel, mediated by tourist wine involvement dimension. A Structural Equation Modeling (SEM) approach is used to develop and to test conceptualized relationships between one exogenous and two endogenous constructs: tourist perceptions about Madeira Island attractiveness (destination image), tourist Madeira wine involvement and global satisfaction constructs. The findings indicate that global tourist satisfaction is directly influenced by the level of tourist wine involvement and indirectly by tourist Madeira Island image. The police implications of the results must be integrated in the international context of wine tourism market segment in order to explore additional exchange profits from this economic activity...

Effect of bentonite characteristics on the elemental composition of wine

Catarino, Sofia; Madeira, M.; Monteiro, F.; Rocha, F.; Curvelo-Garcia, A.S.; Sousa, R.Bruno
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
Publicado em //2008 ENG
Relevância na Pesquisa
46.37%
Physical, chemical, and mineralogical characteristics of six bentonites were assessed and related to their elemental release to wine. Extraction essays of bentonites in wine at three pH levels were carried out. The multielemental analysis of bentonites and wines was performed by atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Bentonite addition resulted in significantly higher concentrations of Li, Be, Na, Mg, Al, Ca, Sc, V, Mn, Fe, Co, Ni, Ga, Ge, As, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Ba, W, Tl, Bi, and W. In contrast, the concentrations of B, K, Cu, Zn, and Rb significantly decreased. A strong correlation between Na concentrations of treated wines and its content in bentonite exchange complex was observed. Al and Fe contents reflected bentonite extractable aluminous and ferruginous constituents, while Be, Mg, Ca, V, Mn, Ni, Ge, Zr, Nb, Mo, Sn, Sb, Tl, Pb, and U concentrations reflected the elemental composition of bentonites. Several nonconformances with OIV specifications demonstrated the need for an effective control.

Color measurement using a smartphone applied to Madeira wines

Silva, José Carlos Vieira da
Fonte: Universidade da Madeira Publicador: Universidade da Madeira
Tipo: Dissertação de Mestrado
Publicado em //2015 ENG
Relevância na Pesquisa
66.63%
Computer vision is a field that uses techniques to acquire, process, analyze and understand images from the real world in order to produce numeric or symbolic information in the form of decisions [1]. This project aims to use computer vision to prepare an app to analyze a Madeira Wine and characterize it (identify its variety) by its color. Dry or sweet wines, young or old wines have a specific color. It uses techniques to compare histograms in order to analyze the images taken from a test sample inside a special container designed for this purpose. The color analysis from a wine sample using an image captured by a smartphone can be difficult. Many factors affect the captured image such as, light conditions, the background of the sample container due to the many positions the photo can be taken (different to capture facing a white wall or facing the floor for example). Using new technologies such as 3D printing it was possible to create a prototype that aims to control the effect of those external factors on the captured image. The results for this experiment are good indicators for future works. Although it’s necessary to do more tests, the first tests had a success rate of 80% to 90% of correct results. This report documents the development of this project and all the techniques and steps required to execute the tests.

Olfactory perception threshold assessment of volatile acidity in Madeira wines

Miranda, Andreia Fátima Santos
Fonte: Universidade da Madeira Publicador: Universidade da Madeira
Tipo: Dissertação de Mestrado
Publicado em /02/2015 ENG
Relevância na Pesquisa
56.9%
Madeira wine is a fortified wine with impact in the Madeira Island’s economy. Similarly to other wines, its acidity should be well controlled in order to ensure Madeira wine quality, mostly the volatile acidity. Due to Madeira wine complex flavour, it is crucial to get a better knowledge about the volatile acidity impact in its features, namely determine the perception limit of acetic acid and ethyl acetate, as both are the main contributors for volatile acidity. Firstly, the olfactory perception threshold of volatile acidity was assessed by a trained and an untrained panel, using 5 and 10 years-old Sercial and Malvasia wines. Moreover, the current work also presents the evolution of organic acids, acetic acid and ethyl acetate during 540 days of ageing of Madeira wines (Malvasia, Bual, Verdelho and Sercial), comparing the same wines aged by both traditional ageing processes: canteiro and estufagem. Other wine samples, aged in wood casks (canteiro) for at least 5 years, were also evaluated. HS-SPME followed by GC-MS analysis was used to determine ethyl acetate concentration and IEC-HPLC-DAD was used for the organic acids determination, including acetic acid. The results indicated that acetic acid and ethyl acetate olfactory perception threshold depends essentially on wine’s age. Concerning acetic acid...

Wine Tourism and Visitor's Perception: A Structural Equation Modeling Aproach

Sampaio, Ana
Fonte: IP -Publishing Ltd . Publicador: IP -Publishing Ltd .
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.91%
The field of wine tourism is emerging at international level as a new product with significant economic potentialities and characteristics that may locate it in the paradigm of sustainable development. This paper analyzes a specific wine tourism segment, Madeira Wine tourism, in the global context of tourist consumer behavior, through perception‟s examination of wineries‟ visitors. Specifically, it is investigated the indirect influence of destination image construct on global tourist satisfaction with the travel, mediated by tourist wine involvement dimension. A Structural Equation Modeling (SEM) approach is used to develop and to test conceptualized relationships between one exogenous and two endogenous constructs: tourist perceptions about Madeira Island attractiveness (destination image), tourist Madeira wine involvement and global satisfaction constructs. The findings indicate that global tourist satisfaction is directly influenced by the level of tourist wine involvement and indirectly by tourist Madeira Island image. The police implications of the results must be integrated in the international context of wine tourism market segment in order to explore additional exchange profits from this economic activity...

Wine purchase and consumption in Portugal - an exploratory analysis of young adults' motives/attitudes and purchase attributes; Compra e consumo de vinho em Portugal - uma análise exploratória das motivações/atitudes e atributos de compra dos jovens adultos

Duarte, Filomena; Madeira, Joana; Barreira, Maria Madalena
Fonte: Estação Vitivinicola Nacional Publicador: Estação Vitivinicola Nacional
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
Relevância na Pesquisa
46.41%
This study, exploratory in nature, examines how motives/attitudes, purchase and consumption behaviour, as well as extrinsic attributes for wine choice, of Portuguese young adult’s (aged less than 35 years), differ from other age segments. With this aim an online survey was used, resulting in 1160 usable responses. Using factor and cluster analysis, based on motivation/attitudes towards wine consumption, four segments were obtained: “Enthusiast”, “Regular”, “Infrequent” and “Convivial” wine drinkers. Results show that despite some similarities, young adults (more represent in the two last clusters), particularly those under 24 years, show signifi cant differences concerning the analysed factors.

Wine Tourism and Visitor’s Perception: A Structural Equation Modeling Approach

Sampaio, Ana
Fonte: IP Publishing Ltd Publicador: IP Publishing Ltd
Tipo: Parte de Livro
ENG
Relevância na Pesquisa
56.9%
Wine tourism is emerging on an international level as a new product with significant economic potential and characteristics that may locate it in the paradigm of sustainable development. This paper analyses a specific wine tourism segment, Madeira wine tourism, in the global context of tourist consumer behaviour, through an examination of the perceptions of visitors to wineries. Specifically, the paper investigates the indirect influence of destination image construct on global tourist satisfaction, mediated by tourist wine involvement. A structural equation modelling (SEM) approach is used to develop and test conceptualized relationships between one exogenous and two endogenous constructs: tourist perceptions about the attractiveness of Madeira Island (destination image), tourist involvement in Madeira wine and global satisfaction constructs. The findings indicate that global tourist satisfaction is influenced directly by the tourists' level of wine involvement and indirectly by their image of Madeira Island. The policy implications of the results must be integrated into the international context of the wine tourism market segment in order to explore additional exchange profits from this economic activity, such as the impact of the country image and perceptions of the wine product on the promotion of wine tourism in Europe.

Multivariate analysis for the classification and differentiation of Madeira wines according to main grape varieties

Câmara, J. S.; Alves, M. A.; Marques, J. C.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /02/2006 ENG
Relevância na Pesquisa
46.47%
In order to differentiate and characterize Madeira wines according to main grape varieties, the volatile composition (higher alcohols, fatty acids, ethyl esters and carbonyl compounds) was determined for 36 monovarietal Madeira wine samples elaborated from Boal, Malvazia, Sercial and Verdelho white grape varieties. The study was carried out by headspace solid-phase microextraction technique (HS-SPME), in dynamic mode, coupled with gas chromatography–mass spectrometry (GC–MS). Corrected peak area data for 42 analytes from the above mentioned chemical groups was used for statistical purposes. Principal component analysis (PCA) was applied in order to determine the main sources of variability present in the data sets and to establish the relation between samples (objects) and volatile compounds (variables). The data obtained by GC–MS shows that the most important contributions to the differentiation of Boal wines are benzyl alcohol and (E)-hex-3-en-1-ol. Ethyl octadecanoate, (Z)-hex-3-en-1-ol and benzoic acid are the major contributions in Malvazia wines and 2-methylpropan-1-ol is associated to Sercial wines. Verdelho wines are most correlated with 5-(ethoxymethyl)-furfural, nonanone and cis-9-ethyldecenoate. A 96.4% of prediction ability was obtained by the application of stepwise linear discriminant analysis (SLDA) using the 19 variables that maximise the variance of the initial data set.

Heterocyclic acetals in Madeira wines

Câmara, J. S.; Marques, J. C.; Alves, A.; Ferreira, A. C. Silva
Fonte: Springer-Verla Publicador: Springer-Verla
Tipo: Artigo de Revista Científica
Publicado em /03/2003 ENG
Relevância na Pesquisa
46.64%
The maturation of Madeira wines usually involves exposure to relatively high temperatures which affect the aroma and flavour composition leading to the formation of the typical and characteristic bouquet of these wines. The formation of heterocyclic acetals (1,3-dioxanes and 1,3-dioxolanes) was investigated in order to determine levels and for possible use as indicators of wine age. The results show a linear correlation of the investigated acetals with wine age but suggest that the acetalization reaction is not particularly affected by the drastic oxidative conditions observed during maturation.

3-Hydroxy-4, 5-dimethyl-2 (5 H)-furanone levels in fortified Madeira wines: Relationship to sugar content

Câmara, José Sousa; Marques, José C.; Alves, Maria A.; Ferreira, António C. Silva
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
Publicado em /09/2004 ENG
Relevância na Pesquisa
46.63%
The maturation of Madeira wines usually involves exposure to relatively high temperatures and humidity levels >70%, which affect the aroma and flavor composition and lead to the formation of the typical and characteristic bouquet of these wines. To estimate the levels of sotolon [3-hydroxy4,5-dimethyl-2(5 H )-furanone] and their behavior over time, 86 aged Madeira wines samples (1-25 years old), with different sugar concentrations, respectively, 90 g L-1 for Boal, 110 g L-1 for Malvazia, 25 g L -1 for Sercial, and 65 g L-1 for Verdelho varieties, were analyzed. Isolation was performed by liquid-liquid extraction with dichloromethane followed by chromatographic analysis by GC-MS. The reproducibility of the method was found to be 4.9%. The detection and quantification limits were 1.2 and 2.0 µgL-1, respectively. The levels of sotolon found ranged from not detected to 2000 µgL-1 for wines between 1 and 25 years old. It was observed that during aging, the concentration of sotolon increased with time in a linear fashion ( r ) 0.917). The highest concentration of sotolon was found in wines with the highest residual sugar contents, considering the same time of storage. The results show that there is a strong correlation between sotolon and sugar derivatives: furfural...

Impact of forced-aging process on Madeira Wine flavor

Silva, Hugo Oliveira e; Pinho, Paula Guedes de; Machado, Beatriz P.; Hogg, Tim; Marques, J. C.; Câmara, José S.; Albuquerque, F.; Ferreira, António C. Silva
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
Publicado em /11/2008 ENG
Relevância na Pesquisa
66.63%
The aim of this study was to determine the optimal temperature and baking time to obtain a Madeira wine considered typical by an expert panel. For this purpose simultaneous descriptive analyses of typical Madeira wines were performed, and seven descriptors were selected: “dried fruit”, “nutty”, “musty”, “baked”, “oak”, “mushroom”, and “brown sugar”. Up to 10 odor-active zones were the most frequently cited by the members of the GC-olfactometry panel as corresponding to the panel’s descriptors. The odor importance of each of the zones reported by the GC-O analysis was ranked by AEDA. Three odor zones were identified as common to both Malvasia and Sercial wines and had retention indices (RI) of 1993 (“brown sugar” and “toasted”), 2151 (“brown sugar”), and 2174 (“nutty”, “driedfruits”);sotolonwasidentifiedasresponsibleforthislastaroma.Severalmoleculeswereselected to be quantified on baked wines on the basis of AEDA results and expected Maillard volatiles, such as sotolon, furfural, 5-methylfurfural, 5-ethoximethylfurfural, methional, and phenylacetaldehyde. It was observed that typicity scores were positively correlated with the concentrations of sotolon and sugar and baking time and negatively with the fermentation length.

Comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry combined with solid phase microextraction as a powerful tool for quantification of ethyl carbamate in fortified wines. The case study of Madeira wine

Perestrelo, Rosa; Petronilho, Silvia; Câmara, José S.; Rocha, Silvia M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /05/2010 ENG
Relevância na Pesquisa
56.74%
An analytical methodology based on headspace solid phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography—time-of-flight mass spectrometry (GC × GC–ToFMS) was developed for the identification and quantification of the toxic contaminant ethyl carbamate (EC) directly in fortified wines. The method performance was assessed for dry/medium dry and sweet/medium sweet model wines, and for quantification purposes, calibration plots were performed for both matrices using the ion extraction chromatography (IEC) mode (m/z 62). Good linearity was obtained with a regression coefficient (r2) higher than 0.981. A good precision was attained (R.S.D. <20%) and low detection limits (LOD) were achieved for dry (4.31 μg/L) and sweet (2.75 μg/L) model wines. The quantification limits (LOQ) and recovery for dry wines were 14.38 μg/L and 88.6%, whereas for sweet wines were 9.16 μg/L and 99.4%, respectively. The higher performance was attainted with sweet model wine, as increasing of glucose content improves the volatile compound in headspace, and a better linearity, recovery and precision were achieved. The analytical methodology was applied to analyse 20 fortified Madeira wines including different types of wine (dry...

New method for determination of (E)resveratrol in wine based on microextraction using packed sorbent and ultra-performance liquid chromatography

Gonçalves, João; Câmara, José S.
Fonte: Wiley-VCH Publicador: Wiley-VCH
Tipo: Artigo de Revista Científica
Publicado em /06/2011 ENG
Relevância na Pesquisa
46.3%
An ultra-fast and improved analytical methodology based on microextraction by packed sorbent (MEPS) combined with ultra-performance LC (UPLC) was developed and validated for determination of (E)-resveratrol in wines. Important factors affecting the performance of MEPS such as the type of sorbent material (C2, C8, C18, SIL, and M1), number of extraction cycles, and sample volume were studied. The optimal conditions of MEPS extraction were obtained using C8 sorbent and small sample volumes (50–250mL) in one extraction cycle (extract–discard) and in a short time period (about 3 min for the entire sample preparation step). (E)-Resveratrol was eluted by 1 250mL of the mixture containing 95% methanol and 5% water, and the separation was carried out on a highstrength silica HSS T3 analytical column (100 mm 2.1 mm, 1.8mm particle size) using a binary mobile phase composed of aqueous 0.1% formic acid (eluent A) and methanol (eluent B) in the gradient elution mode (10 min of total analysis). The method was fully validated in terms of linearity, detection (LOD) and quantification (LOQ) limits, extraction yield, accuracy, and inter/intra-day precision, using a Madeira wine sample (ET) spiked with (E)-resveratrol at concentration levels ranging from 5 to 60mg/mL. Validation experiments revealed very good recovery rate of 9575.8% RSD...

In-depth search focused on furans, lactones, volatile phenols, and acetals as potential age markers of Madeira wines by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry combined with solid phase microextraction

Perestrelo, Rosa; Barros, António S.; Câmara, José S.; Rocha, Sílvia M.
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
Publicado em /03/2011 ENG
Relevância na Pesquisa
56.78%
The establishment of potential age markers of Madeira wine is of paramount significance as it may contribute to detect frauds and to ensure the authenticity of wine. Considering the chemical groups of furans, lactones, volatile phenols, and acetals, 103 volatile compounds were tentatively identified; among these, 71 have been reported for the first time in Madeira wines. The chemical groups that could be used as potential age markers were predominantly acetals, namely, diethoxymethane, 1,1-diethoxyethane, 1,1-diethoxy-2-methyl-propane, 1-(1-ethoxyethoxy)-pentane, trans-dioxane and 2-propyl-1,3-dioxolane, and from the other chemical groups, 5-methylfurfural and cis-oak-lactone, independently of the variety and the type of wine. GC × GC-ToFMS system offers a more useful approach to identify these compounds compared to previous studies using GC−qMS, due to the orthogonal systems, that reduce coelution, increase peak capacity and mass selectivity, contributing to the establishment of new potential Madeira wine age markers. Remarkable results were also obtained in terms of compound identification based on the organized structure of the peaks of structurally related compounds in the GC × GC peak apex plots. This information represents a valuable approach for future studies...

Wine purchase and consumption in Portugal - an exploratory analysis of young adults’ motives/attitudes and purchase attributes

Duarte,Filomena; Madeira,Joana; Barreira,Mª Madalena
Fonte: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional) Publicador: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional)
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
46.41%
This study, exploratory in nature, examines how motives/attitudes, purchase and consumption behaviour, as well as extrinsic attributes for wine choice, of Portuguese young adult’s (aged less than 35 years), differ from other age segments. With this aim an online survey was used, resulting in 1160 usable responses. Using factor and cluster analysis, based on motivation/attitudes towards wine consumption, four segments were obtained: “Enthusiast”, “Regular”, “Infrequent” and “Convivial” wine drinkers. Results show that despite some similarities, young adults (more represent in the two last clusters), particularly those under 24 years, show signifi cant differences concerning the analysed factors.

Release of contaminant elements from bentonites to wine: a contribution to achieve a test solution

Catarino,Sofia; Madeira,M.; Monteiro,F.; Curvelo-Garcia,A.S.; Bruno de Sousa,R.
Fonte: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional) Publicador: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional)
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2006 EN
Relevância na Pesquisa
46.53%
The release of mineral elements from six bentonites to wine and to the test solution established by the OIV was evaluated in order to compare the extraction performance of both solutions. Significant differences between wine and tartaric solution results for thirty-four mineral elements analysed by AAS, ETAAS and ICP-MS were observed, suggesting that the extraction solution proposed by the OIV is not suitable for bentonite quality control purposes. Taking into account bentonite maximum extractable amounts defined by the OIV, some samples showed higher concentrations for Na (B3 and B8), Al (B8), Fe (B5) and As (B9). An additional extraction essay involving two bentonites, wine and two complex test solutions containing the major mineral elements of wine (K, Ca, Na and Mg) and protein (wine protein and BSA) was carried out. Significant differences were observed for all elements with exception of Sc, Mn, Co, W and Bi. For several elements, such as Na, Mg (test solution with BSA) V, Ni, Ga, Zr, Cd, In, Sb, Tl and U, the similarity of wine and test solutions content variations was satisfactory. The protein nature of test solutions seemed to have a decisive role in some element changes, probably related to wine protein and BSA distinct volume. In general...