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Caracterização química de extratos de semente e casca de uva e seus efeitos antioxidante sobre carne de frango processada e armazenada sob refrigeração; Chemical characterization of grape seed and peel extracts and their antioxidant activity on processed and cold stored poultry meat

Shirahigue, Ligianne Din
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 17/07/2008 Português
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A carne de frango apresenta vários problemas no processamento e conservação, sendo a oxidação lipídica um dos principais fatores limitantes da qualidade e aceitabilidade comercial deste produto. A indústria de alimentos busca desenvolver novas formulações que visem melhorar a qualidade e, principalmente, a segurança dos produtos alimentícios. Neste sentido, o uso de antioxidantes de fontes naturais, como os extratos de semente e casca de uva, mostra-se como uma alternativa segura e saudável para o processamento de carne de frango. O objetivo desse estudo foi caracterizar quimicamente extratos de semente e casca de uva das variedades Isabel e Niágara (Vitis labrusca) e determinar a atividade antioxidante e o efeito destes extratos sobre a estabilidade oxidativa e a qualidade da carne de frango processada e armazenada sob refrigeração (4±1ºC), em dois tipos de embalagem (aeróbica e a vácuo). Os compostos fenólicos dos extratos foram quantificados e a identificação feita pelo método da cromatografia líquida de alta eficiência (CLAE). A atividade antioxidante foi determinada pelo método do seqüestro do radical DPPH e pelo método da inibição da peroxidação lipídica. Primeiramente, carnes de frango processadas...

Use of grape polyphenols against carcinogenesis: Putative molecular mechanisms of action using in vitro and in vivo test systems

Gollucke, Andrea P. B.; Aguiar Júnior, Odair; Barbisan, Luis Fernando; Ribeiro, Daniel Araki
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 199-205
Português
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Polyphenols are present in foods and beverages and are related to sensorial qualities such as color, bitterness, and astringency, which are relevant in wine, tea, grape juice, and other products. These compounds occur naturally in forms varying from simple phenolic acids to complex polymerized tannins. Thus, it is reasonable to expect that grape-derived products elaborated in the presence of skins and seeds, such as wine and grape juice, are natural sources of flavonoids in the diet. Carcinogenesis is a multistep process that is characterized by genetic, epigenetic, and phenotypic changes. With increasing knowledge of these mechanisms, and the conclusion that most cases of cancer are preventable, efforts have focused on identifying the agents with potential anticancer properties. The use of grape polyphenols against the carcinogenesis process seems to be a suitable alternative for either prevention and/or therapeutic purposes. The aim of this article is to show the molecular data generated from the use of grape polyphenols against carcinogenesis using in vivo and in vitro test systems. © Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition.

Phenolic composition of the berry parts of hybrid grape cultivar BRS Violeta (BRS Rubea×IAC 1398-21) using HPLC-DAD-ESI-MS/MS

Rebello, Ligia Portugal Gomes; Lago-Vanzela, Ellen Silva; Barcia, Milene Teixeira; Ramos, Afonso Mota; Stringheta, Paulo César; Da-Silva, Roberto; Castillo-Muñoz, Noelia; Gómez-Alonso, Sergio; Hermosín-Gutiérrez, Isidro
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 354-366
Português
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The grape is considered a major source of phenolic compounds when compared to other fruits and vegetables, however, there are many cultivars with distinct characteristics directly linked to phenolic profile. Thus, the present study aimed to identify and quantify, for the first time and in detail, the phenolic compounds present in the skin, flesh and seeds of BRS Violeta grape berry using combination of SPE methodologies and analytical HPLC-DAD-ESI-MS/MS. The study was extended to the different berry parts and the most important grape and wine phenolic families, and has revealed interesting features. Violeta grape has a very thick skin (46% of grape weight) that accumulated the most of grape phenolic compounds: great amount of anthocyanins (3930. mg/kg, as malvidin 3,5-diglucoside), together with also important amounts of flavonols (150. mg/kg, as quercetin 3-glucoside), hydroxycinnamic acid derivatives (HCAD; 120. mg/kg, as caftaric acid), and proanthocyanidins (670. mg/kg, as (+)-catechin); in contrast, it seems to be a low resveratrol producer. Violeta grape seeds accounted for similar proportions of low molecular weight flavan-3-ols (mainly monomers; 345. mg/kg, as (+)-catechin) and proanthocyanidins (480. mg/kg, as (+)-catechin). Violeta grape is a teinturier cultivar...

Polifenois em suco de uva : investigaçao sobre a estabilidade durante o processo e armazenamento; Polyphenol in grape juices : stability during processing and storage

Andrea Pittelli Boiago Gollucke
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/10/2007 Português
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Estudos epidemiológicos demonstraram que alimentos e bebidas contendo polifenóis exercem efeitos fisiológicos benéficos. Sucos de uvas são fontes importantes de flavonóides, principalmente flavan-3-óis em suas formas monoméricas de catequinas [(+)-catequina e (-)-epicatequina]. Os objetivos deste trabalho foram caracterizar e quantificar fenólicos totais (TP), monômeros de catequinas (CAT+EPI), atividade sequestrante de radicais livres (RSA) e específicos atributos sensoriais, durante o processo e armazenamento de sucos de uva comerciais. Sucos concentrados (68° Brix) do s cultivares Concord (CCJ) e Isabel (CIJ) foram amostrados durante o processo e após a concentração e armazenados a 5°C. Sucos de uva pasteurizados integ rais (14 a 19° Brix) de mesmos cultivares (PCJ e PIJ) foram mantidos à temperatura ambiente e luz indireta por 10 meses. Ambas situações simularam as condições de armazenamento industriais/comerciais. TP foi determinado pelo método de Folin-Ciocalteu; CAT+EPI por CLAE com detecção por fluorescência e RSA em ensaio com DPPH. Para o teste sensorial, a análise descritiva quantitativa (ADQ) foi utilizada com a seguinte lista pré-determinada de atributos e descritores: cor, adstringência, gosto amargo...

Production of white wine by Saccharomyces cerevisiae immobilized on grape pomace

Genisheva, Zlatina Asenova; Macedo, S.; Mussatto, Solange I.; Teixeira, J. A.; Oliveira, J. M.
Fonte: Institute & Guild of Brewing Publicador: Institute & Guild of Brewing
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
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White wine was produced with Saccharomyces cerevisiae cells immobilized on grape pomace, by natural adsorption. The support, the main solid waste from the wine industry, consisted of the skins, seeds and stems. Immobilization was tested using different media, namely complex culture medium, raw grape must and diluted grape must. Grape pomace was revealed to be an appropriate support for yeast cell immobilization. Moreover, grape must was shown to be the most suitable medium as immobilized cells became adapted to the conditions in the subsequent alcoholic fermentation in the wine-making process. The wines produced, either with immobilized cells or with free cells, were subjected to chemical analysis by HPLC (ethanol,glycerol, sugars and organic acids) and by gas chromatography (major and minor volatile compounds); additionally, colour (CIELab) and sensory analysis were performed. The use of immobilized systems to conduct alcoholic fermentation in white wine production proved to be a more rapid and a more efficient process, especially when large amounts of SO2 were present in the must. Furthermore, the final wines obtained with immobilized cells demonstrated improved sensory properties related to the larger amounts of ethanol and volatile compounds produced. The more intense colour of these wines could be a drawback...

Growth and 4-ethylphenol production by the yeast Pichia guilliermondii in grape juices

Malfeito-Ferreira, Manuel; Loureiro, Virgilio; Barata, Andre; Nobre, Ana; Correia, Pedro
Fonte: American Society for Enology and Viticulture Publicador: American Society for Enology and Viticulture
Tipo: Artigo de Revista Científica
Publicado em //2006 Português
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The behavior of Pichia guilliermondii strains producing high levels of 4-ethylphenol in synthetic media was studied in wines and grape juices. These strains lost their viability and did not produce 4-ethylphenol after 24 hr of inoculation in red wines with ethanol adjusted to 10 or 12 % (v/v) and pH 3.5, in the absence of free sulphite. Under the same conditions, at 12 % (v/v) ethanol, growth of Dekkera bruxellensis was observed. When grown in single culture in grape juices, selected strains of P. guilliermondii produced high levels of 4-ethylphenol. In mixed grape juice fermentations with Saccharomyces cerevisiae, P. guilliermondii began to die after starter inoculation at 107 cfu/mL and did not produce 4-ethylphenol. Low starter inoculation rates (102 cfu/mL) added 72 hr after P. guilliermondii inoculation resulted in high production of 4-ethylphenol. In conditions mimicking cold pre-fermentative maceration processes, at 10ºC for 72 hr, P. guilliermondii did not grow, while at 25ºC growth attained a 104 fold increase. At this temperature, addition of 200 mg/L potassium metabisulfite after grape crushing did not eliminate P. guilliermondii inoculated at 104 cfu/mL in grape juice of pH 3.57. The possibility that high levels of 4-ethylphenol in wines are due to the activity of P. guilliermondii should be mostly related with uncontrolled growth in contaminated grape juices before starter inoculation. In wines...

Grape must mineralization by high pressure microwave digestion for trace element analysis: development of a procedure

Catarino, S.; Trancoso, I.M.; Sousa, Raul Bruno de; Curvelo-Garcia, A.S.
Fonte: Estação Vitivinicola Nacional Publicador: Estação Vitivinicola Nacional
Tipo: Artigo de Revista Científica
Publicado em //2010 Português
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Analytical Note; The present work describes the development and validation of a high pressure microwave-assisted mineralization procedure for the determination of metals in grape must by spectrometric techniques. Metals of special oenological and food safety importance (Al, Co, Cu, Cd, Pb) were used as model elements to achieve the optimum working conditions. The study was conducted by monitoring their concentration in experimental samples by ETAAS. Different combinations of HNO3 and H2O2 were tested and an optimal volume of 1 mL of each reagent, added to 2 mL of sample, was selected for further studies. In comparison with experimental conditions described in literature for the mineralization of grape must and wine by HPMW, the proposed procedure requires very low reagent consumption. Time and temperature were regarded as factors in the optimization study of microwave oven program, resulting in 72 minutes of extension including ventilation. The procedure trueness and precision were evaluated using grape must and wine samples. For each element three different levels of addition were performed. The recovery range was from 94% (Co) to 113% (Pb) in grape must and from 96% (Cu) to 128% (Al) in wine. Relative standard deviations ranged from 1% (Cd) to 11% (Al) in grape must and from 2% (Cd...

Analytical characteristics and discrimination of Brazilian commercial grape juice, nectar, and beverage

Rizzon,Luiz Antenor; Miele,Alberto
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2012 Português
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The production and commercialization of Brazilian grape juice is increasing annually, mainly due to its typicality, quality, and nutritional value. The present research was carried out in view of the great significance of Brazilian grape juice for the grape and wine industry. The purpose of this study, therefore, was to assess its composition as well as the discrimination between grape juice and other beverages. Twenty four samples of whole, sweetened, and reprocessed grape juices, grape nectar, and grape beverage were evaluated. Classical variables were analyzed by means of physicochemical methods; tartaric and malic acids, by HPLC; methanol, by gas chromatography; minerals, by atomic absorption spectrophotometry. These products were discriminated by the Principal Component Analysis (PCA). Results show that whole and sweetened grape juices were discriminated from other grape products because they featured higher values of total soluble solids, tartaric and malic acids, most minerals, phenolic compounds, and K/Na ratio, whereas grape nectar and grape beverage presented higher values of ºBrix/titratable acidity ratio. Reprocessed juice was discriminated due to its higher concentrations of Li and Na and lower hue.

Simultaneous analysis of 25 phenolic compounds in grape juice for HPLC: method validation and characterization of São Francisco Valley samples

Natividade, M. M. P.; Corrêa, L. C.; Souza, S. V. C.; Pereira, G. E.; Lima, L. C. O.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em 15/08/2013 Português
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A HPLC method for simultaneous determination of 25 phenolic compounds in grape juice was optimized, validated and applied in the characterization of juices produced in São Francisco Valley (SFV), Brazil. The performance char- acteristics of the method were established by assays with standard solutions of phenolic compounds, spiked and unspiked samples. Linearity, matrix effects, trueness, precision, detection and quantification limits were evaluated. Linearity was demonstrated in the concentration ranges tested for all phenolic compounds. Significant matrix ef- fects were not identified for the studied compounds. Mean recoveries ranged from 86.18 to 106.50%, demonstrat- ing no lack of trueness. Precision of the method was confirmed for the 25 phenolic compounds, with acceptable repeatability relative standard deviations (from 0.71 to 9.24%) and within-reproducibility relative standard devia- tions (from 1.34 to 9.26%) for unspiked and spiked samples. The theoretical limits of detection and quantification of the method varied from 0.001 to 0.19 μg mL −1 and 0.003 to 0.37 μg mL −1 , respectively. The results of the valida- tion process showed that the proposed method is fitness for purpose. This method was able to identify simulta- neously 25 phenolic compounds and had advantages such as low consumption of solvents and easy sample preparation. The phenolic profile of the grape juices from SFV varied according the grape cultivar. Phenolics of the anthocyanins and tannins class predominated in red grape juices...

Innovation and adaptation in the Ontario grape and wine industry: An integrated, transdisciplinary response to climate change

Pickering, Kerrie; PIckering, Gary J.; Inglis, Debbie; Shaw, Tony; Plummer, Ryan
Fonte: Brock University Publicador: Brock University
Tipo: Trabalho em Andamento
Português
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With scientific consensus supporting a 4oC increase in global mean temperature over the next century and increased frequency of severe weather events, adaptation to climate change is critical. Given the dynamic and complex nature of climate change, a transdisciplinary approach toward adaptation can create an environment that supports knowledge sharing and innovation, improving existing strategies and creating new ones. The Ontario wine industry provides a case study to illustrate the benefits of this approach. We describe the formation and work of the Ontario Grape and Wine Research Network within this context, and present some preliminary results to highlight the opportunities for innovation that will drive the successful adaption of the Ontario grape and wine industry.; Thank you to all our partners in The Ontario Grape and Wine Research Network. The support of the Ontario Research Fund for Research Excellence Funding (Round 5), Ontario Grape and Wine Research Inc., the Wine Council of Ontario, the Grape Growers of Ontario, and the Winery and Growers Alliance of Ontario is gratefully acknowledged.

Grape sourced bioactives: a potential new treatment strategy for intestinal mucositis and colon cancer.

Cheah, Ker Yeaw
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2012 Português
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Mucositis is a serious condition involving inflammation and ulceration to the lining of gastrointestinal tract that results from cancer chemotherapy. Grape seeds represent a rich source of proanthocyanidins (PAs) which have been reported to be strong antioxidant and chemopreventative agents. This thesis will examine in detail the potential for grape seed PAs to act as novel therapeutic adjunct in cancer treatment. Previously, Cheah et al. (2009) demonstrated that grape seed extract (GSE; 400mg/kg) improved the parameters of intestinal damage in rats with experimentally-induced mucositis. However, its optimal dose and dose responsiveness remained undetermined. In the current study, the effects of increasing GSE doses (400, 600 and 1000mg/kg) on the severity of intestinal mucositis were investigated in a rat model. GSE at higher doses (600 and 1000mg/kg) were more effective than a lower dose (400mg/kg) at ameliorating intestinal injury induced by the chemotherapy agent, 5-Fluorouracil (5-FU) in the proximal small intestine. In addition, no deleterious effects of GSE at these doses were apparent in healthy animals. The promising effects of GSE in a model of mucositis, and its anti-cancer activity, provided the impetus to further investigate its potential impact on the effectiveness of chemotherapy against colon cancer cells. It was decided to characterise the link between the chemical structures of the main polyphenolic compounds within GSE (PAs)...

Grape seed extract dose-responsively decreases disease severity in a rat model of mucositis; concomitantly enhancing chemotherapeutic effectiveness in colon cancer cells

Cheah, K.Y.; Howarth, G.S.; Bastian, S.E.P.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
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OBJECTIVE: Mucositis is a serious disorder of the gastrointestinal tract that results from cancer chemotherapy. We investigated the effects of increasing grape seed extract doses on the severity of chemotherapy in a rat model and its coincident impact on chemotherapeutic effectiveness in colon cancer cells. DESIGN: Female Dark Agouti rats were gavaged with grape seed extract (400-1000 mg/kg) or water (day 3-11) and were injected intraperitoneally with 5-Fluorouracil (150 mg/kg) or saline (control) on day 9 to induce mucositis. Daily metabolic data were collected and rats were sacrificed on day 12. Intestinal tissues were collected for histological and myeloperoxidase analyses. Caco-2 cell viability was examined in response to grape seed extract in combination with 5-Fluorouracil by 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide) assay. RESULTS: Compared with 5-Fluorouracil controls, grape seed extract (400-1000 mg/kg) significantly decreased the histological damage score (P<0.05) in the jejunum. Grape seed extract (1000 mg/kg) increased jejunal crypt depth by 25% (P<0.05) in 5-Fluorouracil treated rats compared to 5-Fluorouracil controls, and attenuated the 5-Fluorouracil -induced reduction of mucosal thickness (25%, P<0.05). Grape seed extract (600 mg/kg) decreased myeloperoxidase activity by 55% (P<0.01) compared to 5-Fluorouracil controls. Grape seed extract was more effective at ameliorating 5-Fluorouracil induced intestinal injury...

Caracterização química e funcional de tomates "Sweet Grape" e Italiano submetidos à desidratação osmótica e adiabática; Chemical and functional quality of mini-tomato Sweet Grape dehydrated and stored

Loro, Ana Carolina
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 05/08/2015 Português
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O tomate é um produto hortícola de importância comercial para o Brasil e seu consumo se dá tanto na forma in natura quanto de produtos processados. O Sweet Grape, híbrido de mini tomate de sabor mais adocicado, pode ser consumido como acompanhamento, tira-gosto ou in natura. No que tange aos tomates in natura, as principais dificuldades de comercialização estão relacionadas às perdas pós-colheita e ao excedente produtivo. Devido ao fato de ser altamente perecível, o processo de desidratação vem sendo uma grande alternativa ao fruto que não apresenta padrões de comercialização in natura e ao excedente produtivo, no entanto pouco se estudou sobre o processamento na variedade híbrida Sweet Grape. O processamento consistiu na desidratação em solução osmótica, seguido de secagem em secador convectivo adiabático. Diante disso, o presente trabalho objetivou estudar técnica de secagem em duas variedades de tomate, Italiano e Sweet Grape, por meio de análises de composição centesimal (umidade, cinzas, lipídios, proteínas, fibras e carboidratos), mineral, antioxidantes (fenólicos, luteína, betacaroteno, licopeno e ácido ascórbico) e sensorial dos tomates in natura e dos produtos desidratados. Na composição centesimal...

Functional genomics of O-glucosyltransferases from Concord grape (Vitis labrusca)

Hall, Dawn.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
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Grape (Vitis spp.) is a culturally and economically important crop plant that has been cultivated for thousands of years, primarily for the production of wine. Grape berries accumulate a myriad of phenylpropanoid secondary metabolites, many of which are glucosylated in plantae More than 90 O-glucosyltransferases have been cloned and biochemically characterized from plants, only two of which have been isolated from Vitis spp. The world-wide economic importance of grapes as a crop plant, the human health benefits associated with increased consumption of grape-derived metabolites, the biological relevance of glucosylation, and the lack of information about Vitis glucosyltransferases has inspired the identification, cloning and biochemical characterization of five novel "family 1" O-glucosyltransferases from Concord grape (Vitis labrusca cv. Concord). Protein purification and associated protein sequencIng led to the molecular cloning of UDP-glucose: resveratrollhydroxycinnamic acid O-glucosyltransferase (VLRSGT) from Vitis labrusca berry mesocarp tissue. In addition to being the first glucosyltransferase which accepts trans-resveratrol as a substrate to be characterized in vitro, the recombinant VLRSGT preferentially produces the glucose esters of hydroxycinnamic acids at pH 6.0...

Análise comparativa do custo de produção e rentabilidade da uva \'Niágara Rosada\' cultivada em diferentes regiões do Estado de São Paulo; Comparative analysis of production costs and profitability of \'Niagara Rosada\' grape grown in different regions of São Paulo State

Cappello, Fernando Perez
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 05/09/2014 Português
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A \'Niágara Rosada\' (Vitis labrusca) é a principal cultivar de mesa produzida no Estado de São Paulo. Esta cultivar apresenta maior rusticidade e menor custo de produção em relação às cultivares de uva fina (Vitis vinifera L.) por ser mais resistente às doenças fúngicas, ter menor custo com mão-de-obra e insumos, pelo menor número de pulverizações e pela ausência de alguns tratos culturais. No Estado de São Paulo, sua produção concentra-se, principalmente, nos Escritórios de Desenvolvimento Rural (EDR) de Campinas, Itapetininga e Jales, e é cultivada sob diferentes sistemas de produção. O objetivo do trabalho foi analisar a viabilidade econômica da cultivar \'Niágara Rosada\' nos principais EDRs produtores do Estado de São Paulo. Para isso, foram realizados painéis e estudos de caso com produtores para elaboração do custo de produção, rentabilidade da cultura e análise de investimento, para o ano de 2012, nas diferentes regiões produtoras. No EDR de Campinas, foi avaliado o período de safra principal e temporã, no qual o Custo Total (CT) foi R$ 1,57 por quilo, com uma Receita Líquida Total (RLT) de R$ 0,89 por quilo de uva. Ao considerar apenas a safra principal do EDR de Campinas, a queda na produção elevou o custo e diminuiu a rentabilidade de forma que o CT foi de R$ 1...

Maturação e qualidade da uva 'Niagara Rosada' após a colheira; Maturation and quality of 'Niagara Rosada' grape after harvest

Daniel Gomes
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 09/08/2012 Português
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A cultivar de uva Niagara Rosada é a principal uva de mesa brasileira e o Estado de São Paulo é seu maior produtor com cerca de 2000 propriedades vitícolas (OLIVEIRA et al. 2008). O seu cultivo está se expandindo, dentre os fatores responsáveis destacam-se: o menor custo de produção em relação ao cultivo de uvas finas; maior rusticidade e menor necessidade de defensivos agrícolas. Apesar dos 79 anos de existência desde sua identificação e das inúmeras vantagens no cultivo, a uva 'Niagara Rosada' possui pouquíssimos estudos sobre sua pós-colheita, maturação ideal na vindima e suas consequências na vida útil dos frutos, e de sua aceitação pelo consumidor. A uva é comercializada freqüentemente abaixo do índice de maturação de 14o Brix indo contra a legislação brasileira. É comercializada imatura, ou seja, pouco doce, ácida e verde, causando malefícios a toda cadeia. Os produtores costumam comercializá-la mesmo fora da legislação vigente argumentando que não suportariam o manuseio, acondicionamento e transporte caso fossem colhidas no estádio recomendado. Diante do exposto o objetivo desse trabalho foi investigar a variação da qualidade e da vida útil da uva 'Niagara Rosada' quando colhida em diferentes estádios de maturação. Estabelecer faixas de maturação que proporcionem maior vida útil e aceitação dos consumidores e questionar a validade do parâmetro de colheita 14o Brix da legislação brasileira com outro parâmetro a razão sólidos solúveis / acidez titulável...

Detection of ochratoxin A in tropical wine and grape juice from Brazil

Terra, M. F.; Prado, G.; Pereira, G. E.; Ematné, H. J.; Batista, L. R.
Fonte: Society of Chemical Industry Publicador: Society of Chemical Industry
Tipo: Artigo de Revista Científica
Publicado em 27/07/2012 Português
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Ochratoxin A (OTA) is the main mycotoxin found in grapes, wines and grape juices and is considered one of the most harmful contaminants to human health. In this study, samples of tropical wines and grape juices from different grape varieties grown in Brazil were analysed for their OTA content by high-performance liquid chromatography. The detection and quantification limits for OTA were 0.01 and 0.03 μg L−1 respectively. OTA was detected in 13 (38.24%) of the samples analysed, with concentrations ranging from <0.03 to 0.62 μg L−1. OTA was not detected in any of the grape juice samples. Most of the red wine samples proved to be contaminated with OTA (75%), while only one white wine sample was contaminated. However, the OTA levels detected in all samples were well below the maximum tolerable limit (2 μg L−1) in wine and grape juice established by the European Community and Brazilian legislature. The results of this study indicate a low risk of exposure to OTA by consumption of tropical wines and grape juices from Brazil.

Preservation of the endogenous antioxidant system of fish muscle by grape polyphenols during frozen storage

Pazos, Manuel; González, M. Jesús; Gallardo, José Manuel; Torres, Josep Lluís; Medina, Isabel
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 22195 bytes; application/pdf
Português
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6 pages, 2 figures, 2 tables.-- Printed version published May 2005.; The capacity of a phenolic extract, OW, obtained from grape (Vitis vinifera) by-products, and of a purified fraction of procyanidins from OW, fraction IV, for preservation of endogenous antioxidants of fatty fish was investigated during frozen storage. They were used in muscle concentrations of 0.01% (w/w). Grape polyphenols were compared with propyl gallate, a synthetic antioxidant. The exogenous compounds were added to minced mackerel (Scomber scombrus) muscle and horse mackerel (Trauchurus trauchurus) fillets, before freezing at –10 °C. The results demonstrated that grape polyphenols and propyl gallate inhibit the depletion of endogenous agr-tocopherol, ubiquinone-10 and total glutathione. Grape polyphenols and propyl gallate showed similar efficiency for preservation of ubiquinone, in both minced and filleted muscle, and total glutathione, in minced muscle. Total glutathione in the fillets was better maintained by propyl gallate than grape polyphenols. The endogenous antioxidant more efficiently preserved by grape polyphenols and propyl gallate was agr-tocopherol. Its loss elapsed faster in the order control> OW>fraction IV>propyl gallate. The depletion of agr-tocopherol was highly correlated with the evolution of lipid oxidation. The development of lipid oxidation was repressed...

Grape must mineralization by high pressure microwave digestion for trace element analysis: development of a procedure

Catarino,S.; Trancoso,I.M.; Sousa,R. Bruno de; Curvelo-Garcia,A.S.
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 Português
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The present work describes the development and validation of a high pressure microwave-assisted mineralization procedure for the determination of metals in grape must by spectrometric techniques. Metals of special oenological and food safety importance (Al, Co, Cu, Cd, Pb) were used as model elements to achieve the optimum working conditions. The study was conducted by monitoring their concentration in experimental samples by ETAAS. Different combinations of HNO3 and H2O2 were tested and an optimal volume of 1 mL of each reagent, added to 2 mL of sample, was selected for further studies. In comparison with experimental conditions described in literature for the mineralization of grape must and wine by HPMW, the proposed procedure requires very low reagent consumption. Time and temperature were regarded as factors in the optimization study of microwave oven program, resulting in 72 minutes of extension including ventilation. The procedure trueness and precision were evaluated using grape must and wine samples. For each element three different levels of addition were performed. The recovery range was from 94% (Co) to 113% (Pb) in grape must and from 96% (Cu) to 128% (Al) in wine. Relative standard deviations ranged from 1% (Cd) to 11% (Al) in grape must and from 2% (Cd...

Integrative effects of vine water relations and grape ripeness level of Vitis vinifera L. cv. Shiraz/Richter 99. II. grape composition and wine quality

Hunter,J.J.; Volschenk,C.G.; Novello,V; Pisciotta,A.; Booyse,M.; Fouché,G.W.
Fonte: South African Journal of Enology and Viticulture Publicador: South African Journal of Enology and Viticulture
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 Português
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Regulation of grapevine water status is a common practice to manipulate grape composition and wine quality. In this investigation the effect of plant water status (two field water capacity-based irrigation levels, 75% and 100%, applied at single and combined vine developmental stages) and ripeness level (harvesting at different soluble solid levels) on grape composition and wine quality of Vitis vinifera L. cv. Shiraz/ Richter 99 was determined. Integrative effects of vine water relations and grape ripeness level, specifically in a Mediterranean high winter rainfall area, have not yet been investigated systematically. Source:sink mechanisms and dynamics and compositional and physical changes during both green berry and ripening periods (and in response to environment changes), seemed critical for the final grape composition and wine quality/style. Despite relatively favourable conditions of the experiment terroir, additional water was still required to obtain best grape and wine quality. Skin colour and total phenolic contents were stimulated in particular by 75% (field water capacity) pea size (PS) irrigation, post-véraison (PV) irrigation and 75% pea size+post-véraison irrigation, until the last harvest stage. Treatments that included post-véraison irrigation were not negative in terms of ripening parameters. Increasing total soluble solids with ripening were not followed in parallel by anthocyanin potential. Anthocyanin extractability increased with ripening. A late...