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Competitividade internacional das exportações brasileiras de manga e de uva; International competitiveness of brazilian exports of mangoes and grapes

Diz, Luís André da Costa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/05/2008 PT
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Este trabalho tem como objetivo analisar a competitividade das exportações brasileiras de manga e de uva no mercado internacional no período de 1989 a 2005. Para tanto, utilizou-se o modelo de Constant Market Share (CMS) e o modelo de Vantagem Comparativa Revelada (VCR) para evidenciar os principais fatores responsáveis pela rápida expansão das exportações nacionais para esses dois produtos, além de realizar uma análise comparativa entre as duas culturas selecionadas. O primeiro modelo busca analisar as causas de variação da quantidade (ou valor) exportada de um produto pelo país em questão em relação ao tempo, gerando três dimensões explicativas para a variação das exportações: o efeito dimensão, o efeito distribuição e o efeito competitividade. O efeito dimensão mostra como o crescimento das exportações mundiais afetou o crescimento das exportações do país analisado. O efeito distribuição refere-se às exportações para países de maior ou menor dinamismo. Por resíduo, descontando-se os demais efeitos temos o termo competitividade.Para a geração dos resultados foi necessária a sub-divisão do período de análise em três grupos trienais: 1989/1990/1991, 1994/1995/1996 e 2003/2004/2005.O modelo de Vantagem Comparativa Revelada parte do pressuposto de que o país em questão tende a se especializar nas exportações de produtos que ofereçam vantagens competitivas. Para tanto...

Estudo comparativo do perfil metabolômico e proteômico de uvas (Vitis vinifera) durante o processo de maturação utilizando ferramentas bioanalíticas; Comparative study of metabolomic and proteomic profiles of grapes (Vitis vinifera) during ripening using bioanalytical tools

Fraige, Karina
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 13/07/2012 PT
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A análise da composição química das uvas é de grande importância para avaliar a data da colheita e a produção de vinhos de qualidade. O estudo do metabolismo das uvas é essencial para definirem-se em quais etapas os metabólitos são produzidos, assim como as proteínas e genes que regulam esses processos. Açúcares, polifenóis e ácidos orgânicos são importantes classes de metabólitos relacionados com o desenvolvimento de uvas. Os açúcares são os compostos que primeiramente indicam a data de colheita, sendo substâncias-chave em diversos processos biológicos. Os polifenóis tem se destacado por sua atividade antioxidante, além de participarem dos mecanismos de defesa da planta. Os ácidos orgânicos são responsáveis pela qualidade organoléptica e estão envolvidos em vários processos metabólicos. As proteínas não contribuem de forma significativa para o valor nutricional, mas são importantes marcadores de variedade para verificar adulterações de vinhos. O Rio Grande do Sul é responsável por grande parte das uvas produzidas no país, e recentemente o Vale do São Francisco tem se destacado na produção destas frutas. Em regiões do Sudeste um manejo de podas diferenciado vem sendo feito para a obtenção de uvas com bons índices de maturação e resistência a doenças fúngicas. Uvas produzidas em Água Vermelha e Louveira...

The grapes of wrath: o romance como instrumento de transformação social; The grapes of wrath: the Novel as an Instrument of Social Change

Gonçalves, Janaina
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/12/2014 PT
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Este trabalho tem por objetivo uma análise do romance The Grapes of Wrath, de John Steinbeck, de forma a sugerir alguns aspectos determinantes para a atuação marcante do romance em seu contexto sociopolítico. Ou seja, por meio da observação das relações entre o contexto geral de sua criação e aspectos internos do texto, pretendemos desenvolver algumas hipóteses norteadoras para entender a capacidade do romance de atuar como instrumento de tranformação social.; The aim of this work is an analysis of the novel The Grapes of Wrath, by John Steinbeck, in order to suggest some determining aspects for the outstanding performance of the novel on its sociopolitical context. That is, by observing the relationship between the overall context around its creation and internal aspects of its text, we intend to develop some guiding hypotheses to understand the ability of this novel to act as an instrument of social change.

Determination of ochratoxin a in wine grapes : comparison of extraction procedures and method validation

Serra, Rita; Mendonça, Carla; Abrunhosa, Luís; Pietri, Amedeo; Venâncio, Armando
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica
Publicado em //2004 ENG
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A method for determination of ochratoxin A (OTA) in wine grapes is described, using extraction with a hydrogen carbonate and polyethylene glycol (PEG) solution (5% NaHCO3 and 1% PEG 8000), followed by immunoaffinity clean-up and liquid chromatography with fluorescence detection. Validation was made with spiked samples, in levels of 0.05 and 1µg kg−1, with average recovery rates of 76% and relative standard deviations in repeatability and intermediate precision conditions of 8 and 12%, respectively. The limit of detection and limit of quantification in grapes were established at 0.004 and 0.007 µg kg−1, respectively. To evaluate further the accuracy and efficiency of this method, naturally contaminated grapes were also analysed by another method that involves extraction with acidified methanol, at levels ranging from 0.05 to 37 µg kg−1, and the results compared. A good correlation (r = 0.9996) was found, with better performances in terms of precision for the new method. A survey was conducted on wine grapes from 11 Portuguese vineyards, during the harvest of 2002, using the proposed method. OTA was detected in three out of the 11 samples, at levels ranging from 0.035 to 0.061 µg kg−1. The new method meets all the criteria of the European Commission directive 2002/26/CE...

Mycotoxin-producing and other fungi isolated from grapes for wine production, with particular emphasis on ochratoxin A

Serra, Rita; Braga, A. C.; Venâncio, Armando
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2005 ENG
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Mycotoxins are toxic secondary metabolites produced by filamentous fungi that have been detected in food commodities, including grapes and wine. A survey was conducted to assess mycotoxin-producing fungi in grapes destined for wine production. The mycotoxigenic capacity of the isolates was tested in culture media. Grapes were analyzed by plating methods from 4 Portuguese wine-growing regions at 3 maturation stages (pea berry, early veraison and ripe berry) between 2001 and 2003. From the 10 602 strains detected and identified, the most frequent genera were Cladosporium (25%), Alternaria (24%), Botrytis (15%), Penicillium (9%) and Aspergillus (8%). Most (92.0%) were nonmycotoxigenic or produced mycotoxins of unknown relevance to health. Potential producers of ochratoxin A (OTA) (Aspergillus niger aggregate, 5.4%, Aspergillus carbonarius, 0.6%) and trichothecenes (Fusarium spp., 0.4%; Trichothecium roseum, 0.8%) were the most frequent mycotoxigenic species isolated from grapes. OTA was detected in all cultures of A. carbonarius and 4% of A. niger aggregate strains. There was potential for OTA and trichothecene production in grapes by A. carbonarius and T. roseum, respectively, prior to harvest time. Data presented herein indicate that A. carbonarius is most likely to occur in vineyards with Mediterranean climates...

Fungi and ochratoxin A detected in healthy grapes for wine production

Serra, Rita; Mendonça, Carla; Venâncio, Armando
Fonte: The Society for Applied Microbiology Publicador: The Society for Applied Microbiology
Tipo: Artigo de Revista Científica
Publicado em //2006 ENG
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Aims: The mycoflora of healthy grapes (i.e. without visible symptoms of rot) for wine production in Portuguese winemaking regions was assessed and its potential for ochratoxin A (OTA) production evaluated. The OTA content of grapes was also determined. Methods and Results: A total of 386 fungal strains were isolated by plating methods. The most frequent genera found in grapes were non-ochratoxigenic species: Cladosporium (28%), Penicillium (24%), Botrytis (13%) and Aspergillus (9%). Two OTA-producing strains were isolated, belonging to the species Aspergillus carbonarius and Aspergillus ochraceus. OTA was detected in three of four grape samples, up to 116 ng lֿ¹. Conclusions: OTA is being produced in healthy berries by Aspergillus species, namely A. carbonarius, at levels below the maximum recommended limit of 2000 ng lֿ¹ in wine. Significance and Impact of the Study: The OTA concentration detected in healthy Portuguese grapes does not represent a risk to wine regarding the legal limit established.; EC, Quality of Life Program (QoL), Key Action 1 (KA1) on Food, Nutrition and Health; Fundação para a Ciência e a Tecnologia (FCT)

Ochratoxin A occurrence and formation in Portuguese wine grapes at various stages of maturation

Serra, Rita; Mendonça, Carla; Venâncio, Armando
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /09/2006 ENG
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A total of 93 Portuguese grape samples destined for wine production were examined for the presence of ochratoxin A (OTA) and the OTA producing fungi Aspergillus carbonarius and A. niger aggregate. Samples came from 11 vineyards from four winemaking regions in the North and South of the Portuguese mainland, during the harvest seasons of 2001, 2002 and 2003. Grapes were examined at 3 maturation stages, from setting to the harvesting period, to evaluate when contamination with OTA producing fungi and OTA synthesis occur. The detection of fungi in grape samples was made by plating methods with and without surface disinfection. OTAwas formed by 14% of the 650 isolates tested. Most of the OTA producing strains (96%) were isolated at harvest time. At this stage, the percentage of grape samples with OTA producing strains detected without surface disinfection was 56%. With surface disinfection, A. carbonarius was isolated from 10% of the samples. OTAwas detected in grapes at the 3 maturation stages. The average OTA concentrations in 60 samples at pea berry (28 samples), early veraison (22 samples) and ripe berry (20 samples) were 263, 149 and 35 ng/kg, respectively. Experiments with an A. carbonarius strain demonstrated that OTA production differs significantly with the composition of the berries at different maturation stages (P<0.001)...

Application of classification-tree models to characterize the mycobiota of grapes on the basis of origin

Serra, Rita; Lourenço, Anália; Belo, Orlando; Venâncio, Armando
Fonte: Asociación Española de Especialistas en Micología Publicador: Asociación Española de Especialistas en Micología
Tipo: Artigo de Revista Científica
Publicado em //2006 ENG
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Classification-tree(CT) models are a simple and robust exploratory data analysis technique that can be used in classification, regressions and summaries of data. They distill complex ecological relationships into simplified rules and identify the species necessary for sample classification on the basis of detailed ecological inventories. The usefulness of this technique to characterize and represent differences in the grape mycobiota of distinct origins was evaluated. Grapes from four Portuguese winemaking regions were selected for a 3-year study: Alentejo, Douro, Ribatejo and Vinhos Verdes. The mycobiota of grapes was assessed with planting methods and the frequencies of isolations of the fungal taxa identified in 32 samples were used as a training dataset. The CT algorithm selected the fungal taxa and respective frequencies to classify grapes according to its region of origin. The ten-fold cross-validation technique was used for model evaluation. The success rate of the model was quantified and expressed in the number of correctly classified samples overall and into region. Furthermore, model refinement was performed using attribute selection algorithms and class redefinition. A simple tree model was generated that classified grapes into three regional origins: Douro...

Sour rot-damaged grapes are sources of wine spoilage yeasts

Malfeito-Ferreira, Manuel; Loureiro, Virgilio; Barata, Andre; Gonzalez, Sara; Querol, Amparo
Fonte: FEMS - Patrizia Romano Publicador: FEMS - Patrizia Romano
Tipo: Artigo de Revista Científica
Publicado em //2008 ENG
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Minireview; Yeast species of sound and sour rot-damaged grapes were analysed during fermentation and grape ripening in the vineyard, using general and selective culture media. During 2003 and 2004 vintages, microvinifications were carried out with sound grapes to which different amounts of grapes with sour rot were added. The wine spoilage species Zygosaccharomyces bailii was only recovered during fermentations with sour rot, reaching 5.00 log CFUmL 1 (2003) and 2.48 log CFUmL 1 (2004) at the end of fermentation. The study of yeast populations during the sour rot ripening process (2005 vintage) showed that the veraisondamaged grapes always exhibited higher total yeast counts and a much greater diversity of species. From a total of 22 ascomycetous species, 17 were present only in damaged grapes. The most frequent species were Issatchenkia occidentalis and Zygoascus hellenicus. The spoilage species Z. bailii and Zygosaccharomyces bisporus were consistently isolated exclusively from damaged grapes. This work demonstrates that one of the most dangerous wine spoilage species, Z. bailii, is strongly associated with sour rot grapes and survives during fermentation with Saccharomyces cerevisiae. The use of selective media provides a more accurate characterization of grape contamination species.

Ascomycetous yeast species recovered from grapes damaged by honeydew and sour rot

Malfeito-Ferreira, Manuel; Loureiro, Virgilio; Barata, Andre; Seborro, F.; Belloch, C.
Fonte: Society of Applied Microbiology Publicador: Society of Applied Microbiology
Tipo: Artigo de Revista Científica
Publicado em //2007 ENG
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Aims: To identify ascomycetous yeasts recovered from sound and damaged grapes by the presence of honeydew or sour rot. Methods and Results: In sound grapes, the mean yeast counts ranged from 3.20 ± 1.04 log CFU g-1 to 5.87 ± 0.64 log CFU g-1. In honeydew grapes, the mean counts ranged from 3.88 ± 0.80 log CFU g-1 to 6.64 ± 0.77 log CFU g-1. In sour rot grapes counts varied between 6.34 ± 1.03 and 7.68 ± 0.38 log CFU g-1. Hanseniaspora uvarum was the most frequent species from sound samples. In both types of damage, the most frequent species were Candida vanderwaltii, H. uvarum and Zygoascus hellenicus. The latter species was recovered in high frequency because of the utilization of the selective medium DBDM (Dekkera ⁄ Brettanomyces differential medium). The scarce isolation frequency of the wine spoilage species Zygosaccharomyces bailii (in sour rotten grapes) and Zygosaccharomyces bisporus (in honeydew affected grapes) could only be demonstrated by the use of the selective medium ZDM (Zygosaccharomyces differential medium). Conclusions: The isolation of several species only from damaged grapes indicates that damage constituted the main factor determining yeast diversity. The utilization of selective media is required for eliciting the recovery of potentially wine spoilage species. Significance and Impact of the Study: The impact of damaged grapes in the yeast ecology of grapes has been underestimated

Microbial ecology of sour rotten grapes and their influence on chemical and sensorial wine quality

Barata, André Bernardo Antunes dos Santos Neves
Fonte: ISA/UTL Publicador: ISA/UTL
Tipo: Tese de Doutorado
Publicado em //2011 ENG
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Doutoramento em Engenharia Alimentar - Instituto Superior de Agronomia; The grape berry microbiota is deeply influenced by the sanitary status of grapes. In sound grapes the most frequent yeast species were basidiomycetes, Aureobasidium pullulans, Candida zemplinina and Hanseniaspora uvarum. Sour rotten grapes were mostly colonised by C. zemplinina, H. uvarum, Issatchenkia spp. and Zygoascus hellenicus. The presence of minoritary populations of Zygosaccharomyces bailii was only found in damaged grapes. The acetic acid bacteria Gluconobacter spp. and Gluconoacetobacter spp. were isolated from healthy and injured grapes, while Acetobacter spp. was only associated with sour rot. Sour rot induced an increase of the sugar content, volatile acidity, colour and total phenols of grape juices. Wines with sour rot up to 30% showed equal overall quality after one year of bottle storage. However, wines made with sour rotten grapes showed a distinctive chemical and honey-like aroma. Phenylacetic acid and ethyl phenylacetate, both exhibiting honey-sweet like aromas, emerged as key-aroma compounds of sour rotten wines. The causal agents of sour rot were acetic acid bacteria disseminated by the insect Drosophila spp.. In the absence of these flies...

Ascomycetous yeast species recovered from grapes damaged by honeydew and sour rot

Barata, A.; Seborro, F.; Malfeito-Ferreira, M.; Loureiro, V.
Fonte: Society for Applied Microbiology Publicador: Society for Applied Microbiology
Tipo: Artigo de Revista Científica
Publicado em //2008 ENG
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37.44%
Aims: To identify ascomycetous yeasts recovered from sound and damaged grapes by the presence of honeydew or sour rot. Methods and Results: In sound grapes, the mean yeast counts ranged from 3Æ20 ± 1Æ04 log CFU g)1 to 5Æ87 ± 0Æ64 log CFU g)1. In honeydew grapes, the mean counts ranged from 3Æ88 ± 0Æ80 log CFU g)1 to 6Æ64 ± 0Æ77 log CFU g)1. In sour rot grapes counts varied between 6Æ34 ± 1Æ03 and 7Æ68 ± 0Æ38 log CFU g)1. Hanseniaspora uvarum was the most frequent species from sound samples. In both types of damage, the most frequent species were Candida vanderwaltii, H. uvarum and Zygoascus hellenicus. The latter species was recovered in high frequency because of the utilization of the selective medium DBDM (Dekkera ⁄ Brettanomyces differential medium). The scarce isolation frequency of the wine spoilage species Zygosaccharomyces bailii (in sour rotten grapes) and Zygosaccharomyces bisporus (in honeydew affected grapes) could only be demonstrated by the use of the selective medium ZDM (Zygosaccharomyces differential medium). Conclusions: The isolation of several species only from damaged grapes indicates that damage constituted the main factor determining yeast diversity. The utilization of selective media is required for eliciting the recovery of potentially wine spoilage species. Significance and Impact of the Study: The impact of damaged grapes in the yeast ecology of grapes has been underestimated.

Unraveling the Relationship between Grapes and Health1–4

Pezzuto, John M.; Venkatasubramanian, Venkat; Hamad, Mazen; Morris, Kenneth R.
Fonte: American Society for Nutrition Publicador: American Society for Nutrition
Tipo: Artigo de Revista Científica
Publicado em /09/2009 EN
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As described in this Supplement and elsewhere, consumption of grapes or grape products has been associated with various health benefits. Resveratrol is a unique component of grapes. Following our report on potential cancer chemopreventive activity, thousands of studies have been performed to characterize the mode of action of this substance. Nonetheless, scores of additional chemicals are known to be constituents of grapes, several of which are capable of mediating biological responses. Accordingly, when considering grapes and health, a holistic view appears to be more meaningful, taking into account all chemical components, metabolism, biological potential, biodistribution, absorption, processing, etc. To fathom such a massive amount of information, we propose the creation of focused ontologies. Grapes seem reasonable as a test bed for exploring this approach, especially because a fair amount of results are available with whole-grape powder. In essence, by utilizing a next generation intelligent system, attempts can be made to leverage the existing complexity. This approach involves bringing together all available information, together with expert judgment, and processing this information through a computational “engine” or engines to provide suggested solutions (or implicit functional relationships). Accomplishment of this task...

Fate of ochratoxin A during vinification of Semillon and Shiraz grapes

Leong, S.L.; Hocking, A.; Varelis, P.; Giannikopoulas, G.; Scott, E.
Fonte: Amer Chemical Soc Publicador: Amer Chemical Soc
Tipo: Artigo de Revista Científica
Publicado em //2006 EN
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Semillon and Shiraz grapes containing ochratoxin A (OA) were obtained by inoculation of bunches on the vine with Aspergillus carbonarius. Citric acid content was greater in the inoculated grapes than in healthy grapes. Samples were collected throughout vinification of these grapes and the OA content was quantified using a stable isotope dilution liquid chromatographic-tandem mass spectrometric method. The mass of processed and waste streams during vinification was also noted. Reduction in the amount of OA in juice and wine occurred at every solid-liquid separation stage. The OA concentration (μg/kg) in white and red wine after racking was 4% and 9%, respectively, of that in crushed grapes. This corresponds to 1% and 6% of the total OA content that was initially present in the inoculated grapes. The OA content was divided between solid and liquid phases at each stage of vinification. OA did not appear to be transformed either chemically or biologically by yeast during fermentation, rather was discarded with the marc, juice lees, and gross lees.; Su-lin L. Leong, Ailsa D. Hocking, Peter Varelis, Georgina Giannikopoulos, and Eileen S. Scott

Black Aspergillus species: implications for ochratoxin A in Australian grapes and wine.

Leong, Su-lin L.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 2444100 bytes; 237801 bytes; application/pdf; application/pdf
Publicado em //2005 EN
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Ochratoxin A (OA), a nephrotoxin and potential carcinogen, has been found in many foods, including grapes and grape products. Limits of 2 μg/kg in wine and 10 μg/kg in dried vine fruit have been introduced by the European Union. This study presents information on the ecology of ochratoxin A production by black Aspergillus spp. in Australian vineyards, and the passage of the toxin throughout winemaking. Aspergillus niger and A. carbonarius were isolated from vineyard soils in 17 of 17, and four of 17 Australian viticultural regions, respectively. A. aculeatus was isolated infrequently. All thirty-two isolates of A. carbonarius and three of 100 isolates of A. niger produced OA. Of Australian A. niger isolates analysed for restriction fragment length polymorphisms within the internal transcribed spacer region of 5.8S ribosomal DNA, 61 of 113 isolates, including the three toxigenic isolates, were of type N pattern, and 52 were type T. A selection of these A. carbonarius and A. niger aggregate isolates, as well as imported isolates, were compared using enterobacterial repetitive intergenic consensus (ERIC)-PCR, amplified fragment length polymorphisms (AFLP) and microsatellite markers. ERIC and AFLP clearly differentiated A. niger from A.carbonarius. AFLP further divided A. niger into types N and T. Six polymorphic microsatellite markers...

Glycosylation of smoke-derived volatile phenols in grapes as a consequence of grapevine exposure to bushfire smoke

Hayasaka, Y.; Baldock, G.; Parker, M.; Pardon, K.; Herderich, M.; Jeffery, D.
Fonte: Amer Chemical Soc Publicador: Amer Chemical Soc
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
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The presence of glycosides of smoke-derived volatile phenols in smoke-affected grapes and the resulting wines of Chardonnay and Cabernet Sauvignon was investigated with the aid of high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). All volatile phenols studied (phenol, p-, m-, and o-cresols, methylguaiacol, syringol, and methylsyringol) could be detected as glycosylated metabolites in smoke-affected grapes in a similar fashion to that previously reported for guaiacol. These phenolic glycosides were found in smoke-affected grapes and wines at significantly elevated levels compared to those in non-smoked control grapes and wines. The extraction of these glycosides from grapes into wine was estimated to be 78% for Chardonnay and 67% for Cabernet Sauvignon. After acid hydrolysis, a large proportion of these phenolic glycosides in grapes (50%) and wine (92%) disappeared but the concentrations of volatile phenols determined by gas chromatography-mass spectrometry (GC-MS) were lower than expected. In the case of wine, the majority of the glycosides of phenol, cresols, guaiacol, and methylguaiacol were decomposed upon acid hydrolysis without releasing their respective aglycones, while syringol and methylsyringol were more effectively released.; Yoji Hayasaka...

Quality and enhancement of bioactive phenolics in cv. Napoleon table grapes exposed to different postharvest gaseous treatments

Artés-Hernández, Francisco; Artés Calero, Francisco; Tomás Barberán, Francisco
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 918459 bytes; application/pdf
ENG
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6 pages, 1 figure, 2 tables.-- PMID: 12926872 [PubMed].-- Printed version published Aug 27, 2003.; Ten different gaseous treatments were evaluated for their efficacy in the keeping quality of cv. Napoleon table grapes during 38 days of storage at 0°C followed by 6 days of shelf life at 15°C in air. These storage methods included modified atmosphere packaging (MAP) with and without SO2 or natural fungicides (hexanal and hexenal), two controlled atmospheres (CA), and intermittent and continuous applications of O3. As a control, air atmosphere during cold storage was used. Most of the treatments applied kept the postharvest quality of the grapes, although the best results were obtained by the use of a MAP with 5 kPa of O2 plus 15 kPa of CO2 plus 80 kPa of N2. The total anthocyanin content at harvest was 170 ± 19 μg/g of fresh weight (fw) of grapes, which declined in most of the treatments applied and was reflected in the loss of red color. Peonidin 3-glucoside was detected at all sampling times as the major anthocyanin (always >50% from the total content). Treatments applied kept or decreased the total flavonol content from that measured at harvest (17 ± 1.4 μg/g of fw of berries). However, an increase of up to 2-fold in total stilbenoid content after shelf life for CA and O3 treatments was observed. At all sampling times for almost every treatment piceid concentration remained unaltered or slightly changed...

Real-time PCR based procedures for detection and quantification of Aspergillus carbonarius in wine grapes

Selma, María Victoria; Martínez-Culebras, Pedro V.; Aznar, Rosa
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
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9 pages, 4 tables, 1 figure.; Aspergillus carbonarius is the main species responsible for ochratoxin A accumulation in wine grapes and consequently, its rapid and sensitive detection is increasingly investigated. A new real-time PCR (RTi-PCR) based procedure was developed for the rapid and specific detection and quantification of A. carbonarius in wine grapes. The procedure includes the use of the pulsifier equipment to remove conidia from grapes which prevents releasing of PCR inhibitors, and DNA extraction with the EZNA Fungal DNA kit. It reduced the time for A. carbonarius DNA extraction from grapes to 30 min. Two specific primers (AcKS10L/AcKS10R) delimiting a 161 bp fragment, and a probe were designed and directed to the β-ketosynthase domain of a polyketide synthase from A. carbonarius. Specificity was confirmed by testing primers towards purified DNA from 52 fungal strains, including reference and food isolates. Quantification was linear over at least 5 log units using both serial dilutions of purified DNA and calibrated conidial suspensions from A. carbonarius. The SYBR-Green I and TaqMan RTi-PCR approaches established were able to detect at least 2.4 and 24 genomic equivalents, respectively, using purified DNA. Results obtained from conidial suspensions...

Postharvest Induction Modeling Method Using UV Irradiation Pulses for Obtaining Resveratrol-Enriched Table Grapes: A New “Functional” Fruit?

Cantos Villar, Emma; Espín de Gea, Juan Carlos; Tomás Barberán, Francisco
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
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7 pages, 4 figures, 2 tables.; A modeling method for the induction of resveratrol synthesis by UV irradiation pulses in Napoleon table grapes is proposed. The method is based on the combination of four main parameters: irradiation power (IW), irradiation time (IT), irradiation distance (ID), and number of elapsed days to achieve the highest resveratrol accumulation (Dm). Maximum resveratrol content (11-fold higher than untreated grapes) was achieved using the combination: IW = 510 W, IT = 30 s, ID = 40 cm, and Dm = 3 days. Sensory characteristics and main features of irradiated grapes (color, weight, firmness, flavor, size, ripening index and vitamin C content) remained unaltered after 1 week of storage. UV induction signal migrated to the hidden side of the grape skin with a delay of 3 days as compared to the directly irradiated side. Phenolic compounds were not detected in Napoleon grape flesh. Resveratrol content per standard serving (200 g) of irradiated grape was about 3 mg, an amount more than 10-fold higher than that of untreated Napoleon grapes. This means that a serving of irradiated grape (unpeeled) could supply the resveratrol content equivalent to 3 glasses of a red wine with high resveratrol content (≈ 1 mg/glass). Therefore...

Effect of postharvest ultraviolet Irradiation on resveratrol and other phenolics of Cv. Napoleon table Grapes

Cantos Villar, Emma; García-Viguera, Cristina; Pascual-Teresa, Sonia de; Tomás Barberán, Francisco
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
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7 pages, 6 figures, 3 tables.; In the skin of cv. Napoleon table grapes, the anthocyanins malvidin 3-glucoside (and its acetyl and p-coumaroyl derivatives), cyanidin 3-glucoside, peonidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and delphinidin 3-glucoside were identified by HPLC-DAD-MS. In addition, quercetin 3-glucoside and 3-glucuronide, caffeoyltartaric, piceid, and resveratrol were also detected. The content of most phenolics remained quite constant during postharvest refrigerated storage (10 days at 0 °C) while the resveratrol derivatives increased 2-fold. Postharvest treatments of grapes with UVC and UVB light induced a large increase in resveratrol derivatives (3- and 2-fold, respectively). This means that a serving of mature Napoleon grapes (200 g) provides 1 mg of resveratrol, which is in the range of the amount supplied by a glass of red wine. This can be increased to 2 or 3 mg of resveratrol per serving in grapes that have been irradiated with UVB or UVC, respectively. These results show that refrigerated storage and UV irradiation of table grapes can be beneficial in terms of increasing the content of potentially health-promoting phenolics.; This work has been financially supported by the Spanish CICYT (Grant ALI97-0681). E.C. is grateful to the Spanish MEC for a fellowship.; Peer reviewed