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Available from: Marney Cereda, Jun 30, 2014
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    ABSTRACT: The neutrophils play an essential role in host defenses against infection. When stimulated it responds with an increase of consumption of oxygen known as 'respiratory burst', so generating a great quantity of superoxide anion and hydrogen peroxide, which play an important function antimicrobial, and subsequent degranulation of neutrophils. Polymers are materials largely used in veterinary medicine. Several studies have been carried out to find new polymers and their biocompatibility to medical use. One polymer of cassava's starch (Manihot esculenta crantz) was developed at the Paranaense University's Laboratory of Chemistry - Campus Umuarama City, aiming to analyze the neutrophils degranulation after exposition to this starch. The early results showed a bioinert action of the polymer of cassava's starch on different concentrations when it was in contact with neutrophils. Thus, this material is potentially indicated as biomaterial.
    Ciência Rural 05/2010; 40(5):1103-1108. DOI:10.1590/S0103-84782010005000075 · 0.38 Impact Factor
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    ABSTRACT: Plastic is one of the most common pollutants in the environment. Therefore, the number of studies on the use of biodegradable packaging is increasing. Starch is the primary material used in the production of biodegradable plastics due to its natural abundance and high biodegradability. Yet, the strong hydrophilic character of starch presents a challenge. Therefore, the modification of its structure through oxidation may yield interesting results as the viscosity reduction. The objectives of this work were to obtain cassava (Manihot esculenta Crantz) starch oxidized with 0.8 and 2.0% active chlorine, to develop biodegradable films and characterize their mechanical properties, solubility in water, permeability to water vapor, degree of swelling, and sorption isotherms. Biodegradable films were produced with starch concentrations of 2, 3, 4, and 5% w/w and 25% glycerol (g/100 g starch) added as a plasticizer. Images of the films were obtained with an atomic force microscope and allow to observe a smooth surface and the absence of starch granules in the film produced with oxidized starches. The tensile strength of the biodegradable film produced with oxidized starch (0.8% active chlorine) was 80 MPa. The value of permeability to water vapor was 1.613 × 10−9 kg/day/m/Pa, and the average solubility was 41%. The sorption isotherms showed that biodegradable films made with oxidized starches cannot be used in environments with relative humidity below 35% or above 90%.
    Starch - Starke 10/2011; 63(10):595 - 603. DOI:10.1002/star.201000163 · 1.68 Impact Factor
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    ABSTRACT: In this study, glycerol content and its incorporation method on tensile and barrier properties of biodegradable films (BF) based on cassava starch were analyzed. ANOVA showed that the glycerol incorporation method did not influence the results (P > 0.05), however the glycerol content influenced significantly the tensile and barrier properties of the films (P < 0.05). Films prepared with lower glycerol content presented better tensile and barrier properties than films with higher content. Films were then prepared with addition of clay nanoparticles and their tensile and barrier properties and glass transition temperature were measured. ANOVA indicated that both glycerol and clay nanoparticles influenced significantly the tensile and barrier properties (P < 0.05), diminishing film permeability when clay nanoparticles were present, while the glass transition temperature was not influenced (P > 0.05).
    Lebensmittel-Wissenschaft und-Technologie 04/2012; 46(1). DOI:10.1016/j.lwt.2011.10.018 · 2.42 Impact Factor
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