Extraction and characterization of the starch present in the avocado seed (Persea americana mill) for future applications

Agro-industrial waste causes environmental impacts, and the use of new technologies and materials emerge as minimization alternatives. This work aimed to extract and characterize starch from avocado seeds for future applications. The grains were removed, the starch extracted with a yield of (19.54%), moisture (41.35%), ash (0.33%), titratable acidity (4.64%), lipids (1.68%), proteins (1.60%) and carbohydrates (55.07%). The water activity was 0.986 g/g, the water absorption index 0.333 g/g, the oil absorption capacity 0.691 g/g, and the water solubility 0.888%. The transmittance was 14.30%. The most significant water release in the third freeze cycle. The extracted starch has a high amylose content (39.56%). Thermogravimetric analysis showed stability up to 366 °C, and the granule had an oval shape and smooth surface. With regard to pasting properties of the starches, RVA shows an initial temperature of 88.5 °C and a viscosity of 2880.5 cP at setback. The results suggest that the starch extracted from the avocado seeds provides opportunities for further application of this material to prepare edible and/or biodegradable filmsThis study was financed by the Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) – Finance Code 001. The authors further acknowledge Fundaçao de Amparo à Pesquisa do Estado da Bahia (FAPESB, Code APP/0070/2016) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for grants and financial support and CWP de Carvalho (EMBRAPA) for the RVA analyses. The author Farayde Matta Fakhouri is a Serra Hunter FellowPostprint (published version

Chapter Production and Characterization of Starch Nanoparticles

In recent years, the increasing interest in nanomaterials of natural origin has led to several studies in the area of nano-sized particles from natural polysaccharide polymers, such as cellulose, starch, and chitin. These nanomaterials are used especially as a reinforcement in a polymeric matrix to improve the mechanical and barrier properties of the materials. Starch is a sustainable, abundant biopolymer produced by many plants as a source of storage energy; the main uses of starch are as food and industrial applications. However, recently their use as filler in polymeric matrix (nanoparticles) has attracted attention. Starch nanoparticles (SNPs) can be produced by many methods, using chemical, enzymatic, and physical treatments. The size distribution, crystalline structure, and physical properties of the SNPs may vary from one method to another. These nanoparticles are a very interesting alternatives not only for the polymeric filler but also for the renewability and biodegradability, since they show characteristics inherently of starch granules

Production and Characterization of Starch Nanoparticles

In recent years, the increasing interest in nanomaterials of natural origin has led to several studies in the area of nano-sized particles from natural polysaccharide polymers, such as cellulose, starch, and chitin. These nanomaterials are used especially as a reinforcement in a polymeric matrix to improve the mechanical and barrier properties of the materials. Starch is a sustainable, abundant biopolymer produced by many plants as a source of storage energy; the main uses of starch are as food and industrial applications. However, recently their use as filler in polymeric matrix (nanoparticles) has attracted attention. Starch nanoparticles (SNPs) can be produced by many methods, using chemical, enzymatic, and physical treatments. The size distribution, crystalline structure, and physical properties of the SNPs may vary from one method to another. These nanoparticles are a very interesting alternatives not only for the polymeric filler but also for the renewability and biodegradability, since they show characteristics inherently of starch granules

PBAT/TPS Composite Films Reinforced with Starch Nanoparticles Produced by Ultrasound

The objective of the present work was to study the incorporation of starch nanoparticles (SNP) produced by ultrasound in blends of poly(butylene adipate-co-terephthalate) (PBAT) and thermoplastic starch (TPS). The films were produced by extrusion using varying percentages of SNP (1, 2, 3, 4, and 5% w/w). The SNP were prepared in water without the addition of any chemical reagent. The results revealed that ultrasound treatment results in the formation of SNP less than 100¿nm in size and of an amorphous character and lower thermal stability and low gelatinization temperature when compared with cassava starch. Scanning electron microscopy (SEM) showed that films presented some starch granules. The relative crystallinity (RC) of films decreases with increasing concentration of SNP. The addition of SNP slightly affected the thermal degradation of the films. The DSC results showed that the addition did not modify the interaction between the different components of the films. Mechanical tests revealed an increase in Young’s modulus (36%) and elongation-at-break (35%) with the incorporation of 1% SNP and this concentration reduced the water vapor permeability (53%) and significantly decreased the water absorption of the films, demonstrating that low concentrations of SNP can be used as reinforcement in a polymeric matrixPostprint (published version

Coating of urea granules by in situ polymerization in fluidized bed reactors

Abstract The main objective of the present work is to produce and characterize urea granules coated with polymers prepared with aqueous solutions of acrylic acid and glycerol. Both coating and drying of urea granules were performed in a fluidized bed reactor. Fourier transform infrared spectroscopy analyses indicated the presence of poly(acrylic acid) and acrylic acid / glycerol copolymers on the granule coating and the formation of chemical bonds between urea and the polymer coating. Scanning electron microscopy images showed that the original and coated urea granules presented different characteristics, reinforcing the idea that coating occurs in the fluidized bed. Finally, rates of urea release showed that the coated granules presented slightly slower rates of urea dissolution in water due to the presence of the coating layer. Therefore, it is shown that it is possible to produce coated urea granules through in-situ polymerization onto the granule surface using a fluidized bed

Preparation and characterization of full-spectrum cannabis extract loaded poly(thioether-ester) nanoparticles: In vitro evaluation of their antitumoral efficacy

Δ9 -tetrahydrocannabinol (THC), cannabidiol (CBD) and other natural compounds produced by Cannabis sativa exhibit a wide array of therapeutic effects on the human body. As a result, extracts containing controlled amounts of different cannabinoids, called full spectrum extracts, have generated great interest and are currently being assayed for the management of many diseases including cancer. However, cannabinoids exhibit limited bioavailability due to their low solubility in water and moderate stability. Therefore, developing novel methods of cannabinoid administration or encapsulation that could help to improve the efficacy of treatments based on the use of these compounds is an issue of great interest. The purpose of this study was to develop biobased poly (thioether-ester)-PTEe nanoparticles containing full-spectrum Cannabis extract-CN and assay their potential efficacy in vitro cancer models. To do this we used two different approaches: 1) in-situ thiol-ene miniemulsion polymerization (Me-PTEe) and 2) thiol-ene miniemulsification/solvent evaporation method using PTEe synthesized previously by thiol-ene bulk polymerization (Se-PTEe). In both cases an α,ω-diene-diester monomer assembled from derivatives of castor oil was used. We found that CN-PTEe nanoparticles presented a high encapsulation efficiency with an average diameter of between 91 and 229 nm. Likewise, CN-PTEe nanoparticles reduced the viability to a similar extent as free CN of the cancer cell lines (B16F10, T98, and U87) but not of the non-tumoral NIH3T3 cells. Furthermore, treatment with CN-PTEe nanoparticles mimicked the working mechanism of non-encapsulated cannabinoids (inhibited the AKT signaling pathway and induced autophagy) in BF16F10 melanoma cells. These observations support the idea that the PTEe nanoparticles are effective CN nanocarriers and that they could be assayed in future studies to investigate their potential anticancer activity

Professores e Alunos: o engendramento da violência da escola

The school violence engendering is partially analyzed, considering the violence production in the school environment. This is a bibliographic research with quantitative and qualitative approach. Sources: 77 theses and 15 dissertations carried out in Brazil (2007 to 2012). Data collection and organization: Content Analysis. Main reference: Bernard Charlot and Pierre Bourdieu. Results: the sources showed that Brazilian teachers participate effectively in the school violence engendering, contributing to violence production in the school environment. The students are the main victims. The teacher is less affected by physical and verbal violence. The symbolic power is the most perpetrated by the teacher against the student. The school also plays a major role in it.Analisa-se o engendramento de uma face da violência da escola, tendo em vista a produção da violência em espaço escolar. Pesquisa bibliográfica quanti-qualitativa. Fontes: 77 dissertações e 15 teses produzidas no Brasil (2007 a 2012). Coleta e organização dos dados: Análise de Conteúdo. Fundamentação base: Bernard Charlot e Pierre Bourdieu. Resultados: as fontes apontaram que professores brasileiros são protagonistas na constituição da violência da escola, contribuindo para a produção da violência em espaço escolar. Os alunos são as principais vítimas dessa violência. O professor sofre menos violência física e verbal do que o aluno. A violência simbólica é a mais usada pelo professor contra o aluno. A escola também usa desse expediente

Analisando as pesquisas em educação especial no Brasil Analysing research in special education in Brazil

Nosso objetivo foi examinar a articulação lógica entre o problema e a proposição teórico-metodológica das produções na área da Educação Especial, focando os seus pressupostos epistemológicos. Nos fundamentamos nos pressupostos das tendências empírico-analítica, fenomenológica-hermenêutica, crítico-dialética e do paradigma da complexidade. O procedimento adotado foi interpretar todas as dissertações/teses produzidas nos Programas de Pós-Graduação em Educação e Educação Especial do Brasil, que versam sobre Educação Especial, produzidas nos anos de 2001, 2002 e 2003, disponíveis no banco de teses da CAPES. Encontramos as tendências empírica, fenomenológica e dialética. Os equívocos encontrados foram a não inserção da pesquisa entre as produções na área; ausência de criticidade; não posicionamento numa determinada concepção de educação; construção teórica fundamentada em concepções diferentes; falta de coerência nos pressupostos teórico-metodológicos; não explicitação metodológica; não descrição dos procedimentos éticos; e má elaboração dos resumos. Concluímos pela necessidade da melhoria das dissertações/teses para que possamos avançar na produção de conhecimento na área da Educação Especial.<br>Our objective was to analyze the logical articulation between the problem and the theoretical-methodological proposal of studies in the field of Special Education, focusing on the epistemological issues. We based our study on the empiric-analytical tendencies, phenomenology-hermeneutic, critical-dialectical and the complexity paradigm. The procedure that was adopted was interpreting all dissertations/thesis produced in Post-Graduate programs in Education and Special Education in Brazil, which focus on Special Education, produced in 2001, 2002 and 2003, available online at CAPES' thesis database. We found empirical, phenomenological and dialectic tendencies. The errors encountered included the failure to include the research among the productions in the field; lack of critical approach; lack of making explicit what educational conception the study was based on; theoretical construction based on different conceptions; lack of coherence in the theoretical-methodological proposals; lack of methodological specification; absence of ethical procedural descriptions; and poorly written abstracts. We came to the conclusion that improvements in theses /dissertations are necessary so as to continually move forward in the production of knowledge in the field of Special Education