115 research outputs found
PodridĂŁo vermelha da raiz da soja em cultivos com diferentes sistemas de manejo e coberturas do solo.
O objetivo deste trabalho foi avaliar o efeito dos sistemas de manejo do solo e de coberturas de inverno sobre o nĂșmero de propĂĄgulos de Fusarium spp. no solo, a incidĂȘncia da podridĂŁo?vermelha?da?raiz (PVR) e a produtividade das cultivares de soja CD 206 e FT FĂȘnix. Foram realizados dois experimentos nos anos agrĂcolas de 2006/2007 e 2007/2008. Utilizou-se o delineamento experimental de blocos ao acaso, em parcelas subsubdivididas, com trĂȘs repetiçÔes. Foram avaliados dois sistemas de preparo do solo: plantio direto e revolvimento do solo na profundidade de 25 cm. As coberturas de inverno utilizadas foram: aveia?preta, com duas densidades de plantio; aveia?preta + ervilhaca; azevĂ©m; e pousio. A incidĂȘncia da doença, na safra de 2006/2007, na cultivar FT FĂȘnix, foi menor que na CD 206. Na safra 2007/2008, nĂŁo houve diferença significativa. Houve incremento na produtividade, de 125 kg ha?1, com o solo revolvido, em comparação ao plantio direto. A cobertura com aveia?preta + ervilhaca apresentou maior nĂșmero de propĂĄgulos de Fusarium spp. no solo, na safra de 2006/2007. No entanto, no segundo ano, essa diferença nĂŁo foi observada. Os sistemas de preparo do solo e as coberturas de inverno utilizadas nĂŁo influenciam a incidĂȘncia da PVR em cultivares de soja ou o nĂșmero de propĂĄgulos de Fusarium spp. no solo. O sistema com solo revolvido proporciona aumento de produtividade da soja, no segundo ano de manejo
Banana starch nanocomposite with cellulose nanofibers isolated from banana peel by enzymatic treatment: In vitro cytotoxicity assessment
The potential use of cellulose nanofibers (CNFs) as a reinforcing agent in banana starch-based nanocomposite films was investigated. CNFs were isolated from banana peel (Musa paradisiaca) by enzymatic hydrolysis. Banana starch-based nanocomposite films were prepared with CNFs using the casting method. CNFs effect on cell viability and on nanocomposite films properties was investigated. The cytotoxicity of CNFs was assessed on Caco-2 cell line. CNFs were not cytotoxic at 502000??g/mL. However, CNFs above 2000??g/mL significantly decreased cell viability. Topography analysis showed that the incorporation of CNFs modified the film structure. The nanocomposites exhibited a complex structure due to strong interactions between CNFs and starch matrix, promoting a remarkable improvement on mechanical and water barrier properties, opacity and UV light barrier compared to the control film. CNFs can offer a great potential as reinforcing material for starch-based nanocomposite films, producing a value-added food packaging from a waste material.The authors would like to acknowledge the ïŹnancial support provided by Conselho Nacional de Desenvolvimento CientĂïŹco e TecnolĂłgico (CNPq) (140274/2014-6), Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES) (2952/2011) and CAPES/FCT nĂșmero349/13 for Ph.D internship program. Joana T. Martins acknowledges the Foundation for Science and Technology (FCT) for her fellowship (SFRH/BPD/89992/2012). This study was supported by FCT under the scope of the strategic funding of UID/BIO/ 04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors would also like to acknowledge the Brazilian Nanotechnology National Laboratory (LNNano) for allocation of the TEM, AFM and AFM-Nano IR apparatus.info:eu-repo/semantics/publishedVersio
Oat growth under different nitrogen doses in an eucalyptus alley cropping system in subtropical Brazil.
Foi realizada uma anĂĄlise de crescimento para verificar como a aveia (Avena sativa L. cv. IPR 126) cultivada para grĂŁos responde a um sistema agroflorestal (SAF) com eucaliptos (Eucalyptus dunnii Maiden) no subtrĂłpico brasileiro. A hipĂłtese deste trabalho Ă© que a resposta de crescimento da aveia nĂŁo Ă© modificada pelo nitrogĂȘnio em distĂąncias relativas a faixas de eucaliptos. O objetivo deste estudo foi determinar como o crescimento da aveia Ă© influenciado por nĂveis de nitrogĂȘnio (12 e 80 kg ha-1 de N) em cinco posiçÔes equidistantes entre faixas de linhas duplas de eucaliptos [20 m (4 m x 3 m)] em SAF e em agricultura tradicional de plantio direto. O experimento foi em faixas no delineamento de blocos ao acaso com quatro repetiçÔes. Foram avaliadas as taxas de crescimento relativo e de assimilação lĂquida, fração de massa foliar e taxa de enchimento relativo da panĂcula. O nitrogĂȘnio alterou a resposta do crescimento diferentemente em posiçÔes relativas Ă s faixas de ĂĄrvores, portanto diferentes doses de nitrogĂȘnio devem ser utilizadas nestas posiçÔes para aumentar o crescimento da aveia
Production Systems to Integrate Livestock Grazing and Grain Production in Southern Brazil and Midwestern USA
Agriculture in the USA and Brazil has undergone similar and dramatic changes in the past 20 years. In both countries, production systems have become increasingly specialized. Large farms are characterized by single enterprises, simple crop rotations, and livestock production is segregated from grain production. The lack of diversification and high production costs expose producers to risk from economic swings of single enterprises and greater reliance on pesticides and synthetic fertilizers to maintain profitability, along with greater risk of soil erosion from continuous row crop production. Scientists in southern Brazil and Ohio are collaborating to develop no-tillage systems that integrate livestock grazing with cash grain production. The goal is diversified production systems that are profitable as well as biologically and environmentally sound
Danos causados por bovinos em diferentes espécies arbóreas recomendadas para sistemas silvipastoris.
TrĂȘs espĂ©cies arbĂłreas foram avaliadas quanto aos danos causados por bovinos em pastejo em um sistema silvipastoril implantado na regiĂŁo subtropical do Brasil. As espĂ©cies Schinus terebinthifolius (Raddi), Grevillea robusta (A. Cunn. ex R.Br) e Eucalyptus dunnii (Maiden), foram plantadas em linhas simples, arranjadas em 14 m x 3 m, para comporem um sistema agrossilvipastoril. Durante os primeiros trĂȘs anos a ĂĄrea foi utilizada para produção de grĂŁos em sistema de cultivo em alĂ©ias (silviagrĂcola). ApĂłs 41 meses do plantio das ĂĄrvores, o gado foi introduzido pela primeira vez na ĂĄrea. Cinco classes de intensidade de danos foram estabelecidas: sem dano, baixa, mĂ©dia, alta e extrema. Os danos causados Ă casca do tronco das ĂĄrvores no sistema foram maiores do que os causados Ă s copas. As ĂĄrvores de S. terebinthifolius foram as mais danificadas pelos bovinos. A manutenção de S. terebinthifolius em sistema silvipastoril nĂŁo Ă© recomendada pelo dano que o gado impĂ”e Ă s ĂĄrvores
Exposure to magnetic fields and childhood acute lymphocytic leukemia in SĂŁo Paulo, Brazil
Background: Epidemiological studies have identified increased risks of leukemia in children living near power lines and exposed to relatively high levels of magnetic fields. Results have been remarkably consistent, but there is still no explanation for this increase. in this study we evaluated the effect of 60 Hz magnetic fields on acute lymphocytic leukemia (ALL) in the State of SĂŁo Paulo, Brazil. Methods: This case-control study included ALL cases (n = 162) recruited from eight hospitals between January 2003 and February 2009. Controls (n = 565) matched on gender, age, and city of birth were selected from the SĂŁo Paulo Birth Registry. Exposure to extremely low frequency magnetic fields (ELF MF) was based on measurements inside home and distance to power lines. Results: for 24 h measurements in children rooms, levels of ELF MF equal to or greater than 0.3 microtesla (mu T), compared to children exposed to levels below 0.1 mu T showed no increased risk of ALL (odds ratio [OR] 1.09; 95% confidence interval [95% CI] 0.33-3.61). When only nighttime measurements were considered, a risk (OR 1.52; 95% CI 0.46-5.01) was observed. Children living within 200 m of power lines presented an increased risk of ALL (OR 1.67; 95% CI 0.49-5.75), compared to children living at 600 m or more of power lines. for those living within 50 m of power lines the OR was 3.57 (95% CI 0.41-31.44). Conclusions: Even though our results are consistent with the small risks reported in other studies on ELF MF and leukemia in children, overall our results do not provide support for an association between magnetic fields and childhood leukemia, but small numbers and likely biases weaken the strength of this conclusion. (C) 2011 Elsevier B.V. All rights reserved.Univ SĂŁo Paulo, Fac Saude Publ, Dept Epidemiol, BR-01255 SĂŁo Paulo, BrazilAssoc Brasileira Compatibilidade Eletromagnet, SĂŁo Paulo, BrazilHosp Amaral Carvalho, Jau, BrazilUniv SĂŁo Paulo, Fac Med, BR-14049 Ribeirao Preto, BrazilUniversidade Federal de SĂŁo Paulo, Inst Oncol Pediat, SĂŁo Paulo, BrazilHosp Infantil Darcy Vargas, SĂŁo Paulo, BrazilSanta Casa Misericordia SĂŁo Paulo, SĂŁo Paulo, BrazilHosp Santa Marcelina, SĂŁo Paulo, BrazilUniv Calif Los Angeles, Sch Publ Hlth, Los Angeles, CA 90024 USAUniversidade Federal de SĂŁo Paulo, Inst Oncol Pediat, SĂŁo Paulo, BrazilWeb of Scienc
Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation
[EN] Cassava starch-chitosan films were obtained by melt bending and compression molding, using glycerol and polyethylene glycol as plasticizers. Both the starch/chitosan and the polymer/plasticizer ratios were varied in order to analyze their effect on the physical properties of the films. Additionally, the antimicrobial activity of 70:30 polymer:plasticizer films was tested in cold-stored pork meat slices as affected by chitosan content. All film components were thermally stable up to 200 A degrees C, which guaranteed their thermostability during film processing. Starch and chitosan had limited miscibility by melt blending, which resulted in heterogeneous film microstructure. Polyethylene glycol partially crystallized in the films, to a greater extent as the chitosan ratio increased, which limited its plasticizing effect. The films with the highest plasticizer ratio were more permeable to water vapor, less rigid, and less resistant to break. The variation in the chitosan content did not have a significant effect on water vapor permeability. As the chitosan proportion increased, the films became less stretchable, more rigid, and more resistant to break, with a more saturated yellowish color. The incorporation of the highest amount of chitosan in the films led to the reduction in coliforms and total aerobic counts of cold-stored pork meat slices, thus extending their shelf-life.The authors acknowledge the financial support provided by the Spanish Ministerio de Economia y Competividad (Projects AGL2013-42989-R and AGL2016-76699-R). Author Cristina Valencia-Sullca thanks the Peruvian Grant National Program (PRONABEC Grant).Valencia-Sullca, CE.; AtarĂ©s Huerta, LM.; Vargas, M.; Chiralt, A. (2018). Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation. Food and Bioprocess Technology. 11(7):1339-1349. https://doi.org/10.1007/s11947-018-2094-5S13391349117Alves, V. D., Mali, S., Beleia, A., & Grossmann, M. V. (2007). Effect of glycerol and amylose enrichment on cassava starch film properties. Journal of Food Engineering, 78(3), 941â946.ASTM (1995). Standard test methods for water vapour transmission of materials. In: Standards designations: E96-95. Annual book of ASTM standards (pp. 406-413). Philadelphia, PA: American Society for Testing and Materials.ASTM (1999). Standard test method for specular gloss. In: Designation (D523). Annual book of ASTM standards, Vol. 06.01. Philadelphia, PA: American Society for Testing and Materials.ASTM (2001). Standard test method for tensile properties of thin plastic sheeting. In: Standard D882 annual book of American standard testing methods. Philadelphia, PA: American Society for Testing and Materials.AtarĂ©s, L., Bonilla, J., & Chiralt, A. (2010). Characterization of sodium caseinate-based edible films incorporated with cinnamon or ginger essential oils. Journal of Food Engineering, 100(4), 678â687.Bonilla, J., AtarĂ©s, L., Vargas, M., & Chiralt, A. (2013). Properties of wheat starch film-forming dispersions and films as affected by chitosan addition. Journal of Food Engineering, 114(3), 303â312.Bonilla, J., Fortunati, E., AtarĂ©s, L., Chiralt, A., & Kenny, J. (2014). Physical, structural and antimicrobial properties of poly vinyl alcohol-chitosan biodegradable films. Food Hydrocolloids, 35, 463â470.Bourtoom, T., & Chinnan, M. S. (2008). Preparation and properties of rice starchâchitosan blend biodegradable film. LWT-Food Science and Technology, 41(9), 1633â1641.Cano, A., JimĂ©nez, A., ChĂĄfer, M., GonzĂĄlez-MartĂnez, C., & Chiralt, A. (2014). Effect of amylose: amylopectin ratio and rice bran addition on starch films properties. Carbohydrate Polymers, 111(0), 543â555.Carvalho, A. J. F. (2008). Starch: Major sources, properties and applications as thermoplastic materials. In M. N. Belgacem & A. Gandini (Eds.), Monomers, polymers and composites from renewable resources. Amsterdam: Elsevier.Chillo, S., Flores, S., Mastromatteo, M., Conte, A., Gerschenson, L., & Del Nobile, M. A. (2008). Influence of glycerol and chitosan on tapioca starch-based edible film properties. Journal of Food Engineering, 88(2), 159â168.Commission Regulation, 2005 (EC) No 2073/2005 of 15 November 2005 on microbiological criteria for foodstuffs. In Official Journal of the European Union pp 338/1â338/26.Da RĂłz, A., Carvalho, A., Gandini, A., & Curvelo, A. (2006). The effect of plasticizers on thermoplastic starch compositions obtained by melt processing. Carbohydrate Polymers, 63(3), 417â424.Dang, K., & Yoksan, R. (2015). Development of thermoplastic starch blown film by incorporating plasticized chitosan. Carbohydrate Polymers, 115, 575â581.Dou, B., Dupont, V., Williams, P. T., Chen, H., & Ding, Y. (2009). Thermogravimetric kinetics of crude glycerol. Bioresource Technology, 100(9), 2613â2620.Fang, J., Fawler, P., Eserig, C., GonzĂĄlez, R., Costa, J., & Chamudis, L. (2005). Development of biodegradable laminate films derived from naturally occurring carbohydrate polymers. Carbohydrate Polymers, 60(1), 39â42.Hutchings, J. B. (1999). Food color and appearance (2nd ed.). Gaithersburg, Maryland, USA: Aspen Publishers, Inc..JimĂ©nez, A., Fabra, M. J., Talens, P., & Chiralt, A. (2012a). Edible and biodegradable starch films: A review. Food Bioprocessing Technology, 5(6), 2058â2076.JimĂ©nez, A., Fabra, M. J., Talens, P., & Chiralt, A. (2012b). Effect of re-crystallization on tensile, optical and water vapour barrier properties of corn starch films containing fatty acids. Food Hydrocolloids, 26(1), 302â310.LĂłpez, O., Garcia, A., Villar, M., Gentili, A., Rodriguez, M., & Albertengo, L. (2014). Thermo-compression of biodegradable thermoplastic corn starch films containing chitin and chitosan. LWT-Food Science and Technology, 57(106), 106â1515.Mali, S., Grossmann, M. V. E., GarcĂa, M. A., Martino, M. N., & Zaritsky, N. E. (2006). Effects of controlled storage on thermal, mechanical and barrier properties of plasticized films from different starch sources. Journal of Food Engineering, 75(4), 453â460.Mendes, J. F., Paschoalin, R. T., Carmona, V. B., Sena Neto, A. R. A., Marques, C. P., Marconcini, J. M., Mattoso, L. H. C., Medeiros, E. S., & Oliveira, J. E. (2016). Biodegradable polymer blends based on corn starch and thermoplastic chitosan processed by extrusion. Carbohydrate Polymers, 137, 452â458.Ortega-Toro, R., JimĂ©nez, A., Talens, P., & Chiralt, A. (2014). Properties of starchâhydroxypropyl methylcellulose based films obtained by compression molding. Carbohydrate Polymers, 109, 155â165.Ortega-Toro, R., Morey, I., Talens, P., & Chiralt, A. (2015). Active bilayer films of thermoplastic starch and polycaprolactone obtained by compression molding. Carbohydrate Polymers, 127, 282â290.Pelissari, F., Grossmann, M., Yamashita, F., & Pineda, E. (2009). Antimicrobial, mechanical and barrier properties of cassava starch-chitosan films incorporated with oregano essential oil. Journal of Agricultural and Food Chemistry, 57(16), 7499â7504.Pelissari, F. M., Yamashita, F., GarcĂa, M. A., Martino, M. N., Zaritzky, N. E., & Grossmann, M. V. E. (2012). Constrained mixture design applied to the development of cassava starch-chitosan blown films. Journal of Food Engineering, 108(2), 262â267.Song, R., Xue, R., He, L. H., Liu, Y., & Xiao, Q. L. (2008). The structure and properties of chitosan/polyethylene glycol/silica ternary hybrid organic-inorganic films. Chinese Journal of Polymer Science, 26(05), 621â630.v.Su, J. F., Huang, Z., Yuan, X. Y., Wang, X. Y., & Lim, M. (2010). Structure and properties of carboxymethyl cellulose/soy protein isolate blend edible films crosslinked by Maillard reactions. Carbohydrate Polymers, 79(1), 145â153.Thunwall, M., Boldizar, A., & Rigdahl, M. (2006). Compression molding and tensile properties of thermoplastic potato starch materials. Biomacromolecules, 7(3), 981â986.TomĂ©, L., Fernandes, S., Sadocco, P., Causio, J., Silvertre, A., Neto, P., & Freire, C. (2012). Antibacterial thermoplastic starch- chitosan based materials prepared by melt-mixing. BioResources, 7(3), 3398â3409.Villalobos, R., Chanona, J., HernĂĄndez, P., GutiĂ©rrez, G., & Chiralt, A. (2005). Gloss and transparency of hydroxypropyl methylcellulose films containing surfactants as affected by their microstructure. Food Hydrocolloids, 19(1), 53â61.Xu, Y. X., Kim, K. M., Hanna, M. A., & Nag, D. (2005). Chitosanâstarch composite film: Preparation and characterization. Industrial Crops and Products, 21(2), 185â192.Yang, L., & Paulson, A. T. (2000). Mechanical and water vapour barrier properties of edible gellan. Food Research International, 33(7), 563â570
- âŠ