Caracterização e aplicação de filmes biodegradáveis de amido de incorporados de extrato de própolis-verde

Foram sintetizados filmes biodegradáveis empregando quantidades distintas de amido de milho, glicerina e extrato de própolis-verde em um planejamento fatorial completo com três pontos centrais. Os materiais foram analisados com base em duas propriedades: físicas (espessura, densidade, gramatura e índice de intumescimento) e óptica (transparência). Em todas as propriedades analisadas foi empregado o gráfico de Pareto com a finalidade de verificar o efeito das variáveis e de suas interações. Foram construídas superfícies de resposta para as interações e regressões que foram significativas ao teste conduzido com 95% de confiança. Os resultados permitiram evidenciar que dentre os parâmetros avaliados, o amido de milho foi o que mais influenciou na determinação da espessura, densidade, gramatura e transparência, justificado pela maior quantidade inserida durante a síntese e por ser empregado como agente formador. Por outro lado, na determinação do índice de intumescimento, a glicerina foi o fator de maior influência, já que a mesma é adicionada como agente plastificante. Após a avaliação dos filmes, foram selecionados os que apresentaram as características mais adequadas para aplicação na conservação de bananas-prata (Musa spp.). Os resultados foram promissores na medida em que as frutas embaladas apresentaram menor perda de massa, quando comparadas à amostra sem embalagem, indicando que os biofilmes produzidos são adequados por impedirem as reações de oxidação e deterioração de alimentos. Palavras-chave: Biofilmes. Ferramentas quimiométricas. Conservação de bananas. Characterization and application of biodegradable starch films incorporated with propolis-green extract Abstract Biodegradable films were synthesized using different amounts of corn starch, glycerin and green propolis extract in a complete factorial design with three central points. The materials obtained were analyzed based of two properties: physical (thickness, density, weight and swelling index) and optics (transparency). In all the properties analyzed, the Pareto graph was used in order to verify the effect of the variables and their interactions. Response surfaces were built for interactions and regressions that were significant to the test conducted with 95% confidence. The results showed that among the evaluated parameters, corn starch was the one that most influenced the determination of thickness, density, weight and transparency, justified by the greater quantity inserted during the synthesis and for being used as a forming agent. On the other hand, in the determination of the swelling index, glycerin was the factor of greatest influence, since it is added as a plasticizer. After the evaluation of the synthesized films, those that had the most suitable characteristics for application in the conservation of silver bananas (Musa spp.) were selected. The results were promising insofar as the packaged fruits show less loss of mass, when compared to the sample without packaging, indicating that the biofilms produced are adequate for preventing oxidation and food spoilage reactions. Keywords: Biofilms. Chemometric tools. Banana´s conservation.

Quantifying the thickness of each color material in multilayer transparent specimen based on transmission image

Combing the color transmission image and the Beer–Lambert law shows a great application prospect in quantifying each material in multilayer specimen. Here, a novel, low-cost, and efficient optical algorithm is proposed to predict the thickness of each color material in a multilayer specimen from the color transmission image based on the Beer–Lambert Law. In this work, a normal scanner is employed to achieve the color transmission image of the monochrome transparent films. RGB values represent the transmitted intensity. A linear relationship between the optical depth and physical thickness is observed under different monochromatic lights. It is supposed that for a multilayer transparent film which consisted of different monochrome transparent films, the optical depth is related to the physical thickness of each monochrome transparent component. Therefore, an estimating equation is proposed to predict the thickness of each color material in the multilayer specimen. According to the result, the standard deviation of predicted thickness and practical thickness of each color film in the multilayer specimen is 0.93%. Fairly good agreement and high accuracy are obtained between the practical and predicted values, and the validity of this method is confirmed.

Microstructure and Rutherford Backscattering Spectrometry of Hard/Lubricant Mo-Ti-Al-N Multilayered Coatings Prepared by Multi-Arc Ion Plating at Low Substrate Rotation

To develop the hard and self-lubricating coatings applied for the industrial dry-cutting and die-casting machining tool fields, a series of MoTiAlN/MoN/Mo multilayered coatings were deposited on Si substrates under low substrate rotation by cathodic multi-arc ion plating. XRD, SEM, TEM, RBS, nanoindentation, and tribology tester were used to monitor the phase structure, morphology, component, nanohardness, and friction coefficient of the coatings. It was found that the coatings deposited at various substrate rotations comprised paramount cubic B1 structure TiAlN and Mo2N phases. The micrographs confirmed that the mean modulation period and total physical thickness of multilayered TiAlN/Mo2N coatings with a sharp interface fabricated at 2 revolutions per minute (rpm) were 26 nm and 1.15 μm. The mean nanohardness and friction coefficient were ca. 30 GPa and 0.4, respectively. RBS results along with the SIMNRA code allowed to estimate the total atomic concentrations and the physical thickness of individual sublayer as well as the modulation period of multilayered coatings, which demonstrated an efficiency of this approach for characterization of nano-multilayered structures.

Analysis of the Luminous Field in Fluorescent Optical Layers with Quantum Dots Based on CdSe/CdS/ZnS

The structure of a luminous field in a fluorescence layer containing CdSe/CdS/ZnS-based quantum dots and acting as a transducer in an optical fluorescent sensor is described on the basis of three-flux approximation. Differential equation system of three-flux approximation is solved by numerical technique. It is found that diffuse reflectance of the layer extremely depends on concentration of quantum dots in the layer and its physical thickness. Optimal parameters of the layer required for forming of maximum analytical layer are determined.

STUDI KARAKTERISTIK FISIK DAN MEKANIK EDIBLE FILM PATI UBI JALAR UNGU DENGAN PENAMBAHAN KITOSAN

<p>Edible film is one of alternative packaging which can consume and still protect product from losing nutrition, appearance, flavor, dehydrate and deteriorate at storage and isn’t damage environment. More research using local starch from sweet potato (Ipomea batatas L. poir) was studied. But, characteristic from sweet potato starch shows poor in quality. So, mixing starch with chitosan studied to make characteristic of edible film more useable for wide area. This research to know how is characteristic of edible film starchchitosan. One edible film use 0,8 mL glycerol or 20% (v/w) and chitosan’s soluble 1% acetate acid. One factor uses in this research is amount of chitosan with 3 level 0,5 gram; 1,0 gram; and 1,5 gram. Then, edible film analyzed physical (thickness, solubility and permeability) and mechanic (tensile strength and elongation). Result of research show more chitosan add significantly increased thickness and tensile strength of edible film and significantly decrease solubility and elongation of edible film. But, edible film show no significantly decrease of permeability. Adding more chitosan in edible film starch-glycerol increase edible film thickness to 0,13 –1,90 mm and decrease solubility to 66,87–58,20%. Tensile strength show increase to 1,27–6,90 MPa and elongation decrease to 79,71–46,98%. And for permeability of edible film decrease to 12,40–9,97 (g/ hour m2).</p>