Composição fenólica e atividade antioxidante de resíduos agroindustriais

Atualmente, são produzidas milhões de toneladas de resíduos provenientes do processamento agroindustrial. Muitos deles são ricos em compostos bioativos sendo potenciais fontes naturais dessas substâncias. Assim, este trabalho teve como objetivo avaliar o teor de compostos fenólicos totais, a atividade antioxidante e a composição fenólica de três resíduos gerados por agroindústrias brasileiras: bagaço de uva Isabel (BI) (Vitis labrusca), bagaço de uva Verdejo (BV) (Vitis vinifera) e bagaço de goiaba (BG) (Psidium guajava). Os resultados do teor de compostos fenólicos totais (mg GAE g-1) encontrados nos extratos etanólicos e aquosos dos resíduos foram, respectivamente: BV (20,94±0,46; 8,03±0,43)> BI (16,57±0,19; 4,41±0,01)> BG (3,41±0,09; 1,88±0,06). Alta atividade antioxidante, principalmente em BV e BI, foi verificada nos ensaios realizados (ABTS , DPPH e autooxidação do sistema beta-caroteno/ácido linoléico). Uma forte correlação positiva entre atividade antioxidante e o teor de compostos fenólicos totais foi encontrada. Os compostos fenólicos encontrados, por cromatografia gasosa com espectrometria de massas (CG-EM), foram: ácido gálico, epicatequina, quercetina (BV, BI e BG); ácido isovanílico (BI, BG); ácido p-cumárico (BI); ácido caféico e resveratrol (BV, BI). Esses resultados mostram que os resíduos agroindustriais analisados, particularmente os vinícolas, são ricos em substâncias bioativas e podem ser explorados pela indústria de alimentos e farmacêutica

Applications of Wine Pomace in the Food Industry: Approaches and Functions

Winemaking generates large amounts ofwine pomace, also called grape pomace. This by-product has attracted the attention of food scientists and the food industry, due to its high content in nutrients and bioactive compounds. This review mainly focuses on the different published approaches to the use of wine pomace and its functions in the food industry. Traditionally, wine pomace has been used to obtain wine alcohol, food colorings, and grape seed oil. More recently, research has focused in the production of other value-added products, such as extracts of bioactive compounds, mainly phenols, recovery of tartaric acid, and the making of flours. The most common functions associated with wine pomace products are their use as antioxidants, followed by their use as fortifying, coloring, and antimicrobial agents. These products have mainly been applied to the preparation of meat and fish products and to, a lesser extent, cereal products.Autonomous Government of Castilla y León, Spain, through the research project BU282U13

INFLUENCE OF RED WINE GRAPE PHENOLIC EXTRACTS ON GLUCOSYLTRANSFERASE ACTIVITY, ACIDOGENICITY, AND BIOFILM FORMATION OF STREPTOCOCCUS MUTANS.

Wine grapes are rich sources of potentially bioactive polyphenols. However, phenolic content is variable depending on grape variety, and may be modified during vinification. In this study, we investigated the influence of phenolic extracts from Vitis vinifera (Cabernet Franc and Pinot noir), V. Labrusca (Concord), and Vitis hybrids (Baco noir and Noiret) grapes on several virulence properties of Streptococcus mutans a well-known cariogenic bacterium. Grape phenolic extracts were prepared from whole fruit (WF) and fermented pomace (FP). The anthocyanin and flavan-3-ol content were variable depending on variety and type of extract (WF vs. FP). Nevertheless, all extracts inhibited the activity of GTF B between 60-80% at concentrations as low as 31.2 ug/ml; GTF B synthesizes insoluble glucans, which are critical for the formation, bulk and structural integrity of biofilms. Furthermore, the glycolytic pH-drop by S. mutans cells was inhibited by the extracts without affecting bacterial viability, an effect that can be attributed to partial inhibition of F-ATPase by the extracts (30-65% inhibition at 125 ug/ml). In general, phenolic extracts from V. vinifera were more effective than those from Vitis hybrids. The biological activity of FP was either as effective as or significantly better than WF extracts. The most effective extracts were examined for their ability to disrupt biofilm development by S. mutans using a saliva-coated hydroxyapatite biofilm model. Biofilms were treated for 1 minute twice daily with phenolic extracts from FP of Cabernet Franc and Baco noir. Biofilms treated with the extracts (at 1 mg/ml) resulted in significantly lower amounts of extracellular insoluble polysaccharides than those treated with vehicle control (P<0.01), which agrees well with the GTF B inhibition data. The reduction of insoluble polysaccharides production is highly relevant because they are the main components of the extracellular matrix of biofilms, and are associated with the pathogenesis of dental caries. Overall, the phenolic extracts, especially from pomace, are effective against specific virulence attributes of S. mutans and can disrupt the synthesis of extracellular polysaccharide matrix of biofilms. Fermented pomace could be a potential source for extraction of bioactive compounds for prevention or reduction of oral diseases, such as dental caries.This project was supported by the Field of Food Science and Technology SUNY fellowship program and the National Research Initiative Grant No. 2006-35200-16589 from the USDA Cooperative State Research, Education, and Extension Service Bioactive Food Components for Optimal Health (31.0) program. Travel grants were provided by the Western New York Institute of Food Technologists section and the Department of Food Science

Spatio-Temporal Dynamics of Cholera during the First Year of the Epidemic in Haiti

International audienceBackground: In October 2010, cholera importation in Haiti triggered an epidemic that rapidly proved to be the world's largest epidemic of the seventh cholera pandemic. To establish effective control and elimination policies, strategies rely on the analysis of cholera dynamics. In this report, we describe the spatio-temporal dynamics of cholera and the associated environmental factors

Daily incidence rates (DIRs) and high-risk spatial clusters for each epidemic phase.

<p>Daily incidence rates (DIRs) and high-risk spatial clusters for each epidemic phase.</p

Mapping one year of cholera morbidity and mortality rates in Haiti.

<p>The colored scales represent yearly attack (a) and mortality (b) rates per 10,000 inhabitants in communes of Haiti (from October 16, 2010 to October 15, 2011).</p

Spectral analysis of time series.

<p>Analysis of cases (a), rainfall (b), and cross-wavelet (c) between cases and rainfall are presented. The Y-axes represent length of the wavelet analysis window (from 3 to 26 days) and the color scales represent the spectral values for each length of the analysis window.</p

Impact of local environmental factors during each epidemic phase.

<p>Standardized incidence ratios (p-values) were estimated using the multivariate regression model.</p>*<p>Factor excluded using stepwise analysis.</p>†<p>Significant factors (boldface).</p>‡<p>Non-significant factors kept using stepwise analysis.</p