The present study aimed to maximize the conventional extraction and compare it with the ultrasound-assisted method for extracting bioactive compounds obtained from the red araçá peel. The behavior of ...anthocyanins related to the pre-treatment of the vegetal matrix, employed solvent, extraction kinetics of both methods, the levels of total phenolic compounds, flavonoids and carotenoids, as well as the antioxidant activity were evaluated. The ultrasound-assisted extraction (40 KHz −154 W and 90 min) had an increase of 12% in the levels of anthocyanins (121.85 Eq. mg of cyanidin-3-glycoside/100 g of peel) and a 25% reduction in time extraction compared to conventional extraction by maceration (116.81 Eq. mg of cyanidin-3-glycoside/100 g of peel) using 90% ethanol, for 2 h, pH 1.5, at 40 °C and mass/volume ratio 1 g/10 mL). Analyses of the total phenolic compounds, flavonoids and carotenoids presented promising results for the ultrasound-assisted and conventional extractions, respectively. Analyzes of total phenolic compounds, flavonoids and carotenoids, show promising results for ultrasound-assisted extractions, respectively, indicating that red araçá is rich in bioactive compounds beneficial to human health, in addition to being considered natural pigments that can be used in food.
In this work, new adsorbent composites from the silica precursor tetraethyl orthosilicate (TEOS) and chitosan have been successfully synthesized, denominated 20%Chi, 30%Chi and 40%Chi. The composites ...presented enhanced chemical and physical characteristics, with emphasis on the high surface areas between 374.94 m2/g to 886.31 m2/g. The application of the composites in the model system (TY - Tartrazine yellow dye), presented adsorption capacities dependent on the amount of chitosan in the composite (40%Chi > 30%Chi > 20%Chi). However, from the experimental data of the constituent materials, 30%Chi provided the greatest increase in the adsorption capacity in the monolayer, with values of 36%. This demonstrates that the amount of chitosan in the compound alters the arrangement of adsorption sites. The 30%Chi composite presented life cycle superior to 10 reuse cycles.
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•The addition of silica provided better physical and chemical properties to the developed composites.•The synthesis of the 30%Chi composite enabled an increase in the adsorption capacity of the TY dye.•The 30%Chi composite obtained a surface area of 886.31 m2/g.•The 30%Chi composite was useful for more than 10 adsorption and desorption cycles.
Xerogel; TEOS; Amine groupings; Tartrazine yellow; Adsorption.
Resumo O chocolate é um produto apreciado mundialmente e as tendências do setor apontam para a busca de inovações e a procura por produtos mais saudáveis. Da mesma forma, muitos estudos têm ...demonstrado os benefícios nutricionais da erva-mate (Ilex paraguariensis), dentre eles a atividade antioxidante atribuída ao seu alto teor de compostos fenólicos, tornando-a uma matéria-prima potencial para o desenvolvimento de novos produtos. O presente trabalho tem por objetivo a aplicação de extrato de erva-mate no desenvolvimento de chocolate branco, a fim de elaborar um produto inovador e que atenda às necessidades de saudabilidade dos consumidores. Foram elaboradas formulações com 1%, 3% e 5% de extrato de erva-mate, determinadas por delineamento composto central 22 para o extrato de erva-mate e vanilina. Todas as amostras apresentaram padrão microbiológico em conformidade com o exigido pela legislação brasileira e foram analisadas sensorialmente, a fim de verificar quais eram as mais aceitas pelos consumidores. As formulações com 1% e 3% de extrato de erva-mate foram as mais aceitas para todos os atributos analisados. Os teores de compostos fenólicos variaram de 137,61 a 198,42 mg EAG/100 g e a atividade antioxidante de 83,39 a 179,73 EC50 (mg/mg). Os resultados mostram que o produto desenvolvido apresentou boa aceitabilidade e a aplicação de extrato de erva-mate acrescentou ao chocolate branco compostos fenólicos com ação antioxidante.
A selection of formulations with different polymers and concentrations of green tea extract was conducted for application as interleafs in sliced meat products. Films were formulated using cellulose ...acetate, corn starch, and chitosan with the addition of 1.0, 2.5, and 5.0% green tea extract. Higher antioxidant activity was observed with the 1.0% concentration of green tea extract (P < 0.05), regardless of the formulation, with continuous release of the extract for up to 60 days and average IC50 of 0.09 and 0.31 mg/mL for the corn starch and chitosan active films, respectively. Interleafing the sliced ham resulted in lower lipid oxidation after 60 days of storage (P < 0.05). Starch-based films with green tea extract were effective, significantly reducing lipid oxidation in sliced and interleafed cooked ham, suggesting their potential to extend the shelf life of these refrigerated products.
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•Green tea has antioxidant effects•Incorporating green tea extract into polymer films can make them active•Polymeric films with green tea interspersed in sliced cooked ham have antioxidant properties•The intercalation of sliced ham resulted in less lipid oxidation after 60 days of storage
In this work, the synthesis of zeolites using 1-butyl-3-methylimidazolium chloride C sub(4) MICl as a structure-directing agent was investigated. The organic cation shows effectiveness and ...selectivity for the syntheses of TON zeolites under different reaction conditions compared to the traditional structure-directing agent, 1,8-diaminooctane. The 1-butyl-3-methylimidazolium cation lead to highly crystalline materials and its role as OSDA in our synthesis conditions has been confirmed by characterization techniques. ICP-OES confirms the presence of Al in the samples and super(27) Al MAS NMR analysis indicated that aluminum atoms were incorporated in tetrahedral coordination. Scanning electron microscopy indicated that changing the crystallization condition (static or stirring), zeolites with different crystal size were obtained, which consequently affects the textural properties of the zeolites. Moreover, varying some synthesis parameters MFI zeolite can also be obtained.
Abstract
Dry hybrid synthesized zeolite was added to a fluoroelastomer (FKM). Carbon black filler was also evaluated. The resulting systems were evaluated in terms of rheological, physicochemical and ...morphological characteristics. Replacing carbon black with zeolites decreased the torque maximum (125–144 nM) for all samples. The type of filler has a significant influence on the thermal stability of FKM compounds. The use of x‐ray microtomography (IMX for) on the investigated samples (fluorinated polymers) was shown to be a potential and powerful tool for fractioning the components of the resulting composite material. According to microtomography images, increasing the filler content increases the number of pores, probably due to the greater difficulty in dispersing larger volumes of fillers, which are shown as interconnected conglomerates. The SodC8.5 filler showed a considerable increase in stress at rupture (11 MPa) with only 1 phr, maintaining stability up to 10 phr, while elongation at break increased. The use of Sod and SodC8.5 loads showed an improvement of 15% and 30% in relation to the base compound. Finally, in a thermal stability test at the temperature of liquid N
2
, the SodC8.5 sample showed the best dimensional stability (approx. 7%), verifying the good compatibility between the filler and the fluorinated polymeric matrix.
This work presents the immobilization in situ of commercial lipase from
Candida antarctica
B (CALB) by the sol–gel technique (xerogel) using silica from rice husk ash (RHA) as a source of silicon. ...It was used the Ionic Liquid (IL) 1-octyl-3-methylimidazolium bromide (C8MI.Br) as additive. The immobilized derivatives were characterized per SEM, XRD, and per method BET. The enzymatic activity of xerogels was evaluated with different tests, these being the reactional thermal analysis, immobilization yield, and operational and storage stability. The XDR showed that the obtained xerogels have halos in the region between 15 and 35° (2θ) what characterizes it as amorphous materials. The SEM analysis of xerogel shows irregular particles with dimensions less than 20 μm. The immobilized presented an esterification activity (EA) with 263.2 and 213.8 U/g, with and without IL, respectively, higher than the free enzyme (169.6 U/g). The immobilized, with and without IL, presented a significant improvement in the activity performance in relation to free enzyme for the three reactional temperatures (40, 60, and 80 °C) evaluated. The operational stability demonstrated that is possible to use xerogel without ionic liquid for 17 recycles and 21 recycles in IL presence. This methodology allows the preparation of new highly active and selective enzyme catalysts using the rice husk ash as a source of silicon, and the ionic liquid C8MIBr as additive. Furthermore, the new materials can provide greater viability in the processes, ensuring longer catalyst life.
The present study provides a systematic study of the zeolite synthesis parameters using basic raw materials, such as sodium aluminate, silicon oxide and sodium hydroxide. Sodalite zeolites were ...produced by grinding, homogenizing and heating the reactants without the addition of solvent (water). The effects of the following parameters are evaluated: (i) Si/Al and Si/Na ratios, (ii) reaction time, and (iii) stirring in the reaction medium, which resulted in a set of 15 solids. The Si/Al and Si/Na ratios have a strong effect on the formation of the zeolite phase generated in the presence of higher amounts of sodium, with the ratios Si/Al = 1 and Si/Na = 2 being the minimum satisfactory conditions for crystallization. A low diffusion rate and a longer reaction time and stirring time give rise to samples with higher crystallinities. The resulting zeolites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, water contact angle, small-angle X-ray scattering and thermogravimetric analyses. All materials exhibit dense, spherical and uniform particles with slightly rough surfaces according to SAXS measurements. The solvent-free method is demonstrated to be effective in the synthesis of samples with good crystallinity. This synthesis method is shown to be efficient, fast, economical and environmentally friendly.
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•Hybrid Sodalite zeolites produced by in situ solvent-free synthesis.•Sodalite phase obtained with high crystallinity without add of seed nor template.•Solvent-free route seems to tend to form several nuclei of crystallization.•Only organosilanes with longer alkyl chains presented hydrophobic characteristics.
Hybrid sodalite zeolites were produced by grinding, homogenizing and heating the reactants, including different organosilanes, without the addition of solvent (water). Hybrid sodalite zeolites were ...produced in the presence of triethoxy(octyl)silane (C8Si), 3-chloropropyltrimethoxysilane, triethoxymethylsilane, hexamethyldisiloxane, octadecyltrimethoxysilane (ODS) and chlorotrimethylsilane. The resulting hybrid zeolites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, water contact angle, small-angle X-ray scattering and thermogravimetric analysis. The presence of 6 wt.-% of organosilane introduced in the reaction medium caused no disturbance to the crystal growth. All materials exhibited dense, spherical and uniform particles, with slightly rough surfaces according to SAXS measurements. In the case of octadecylsilane, it appears that the alkyl chains are well packaged and organized, while for octylsilane, a more disordered structure seems to be present. Only organosilanes with longer alkyl chains (C8Si and ODS) show hydrophobic properties. The solvent-free method proved to be effective in synthesizing samples with good crystallinity and hydrophobic characteristics. This synthesis method was shown to be efficient, fast, economical and environmentally friendly.
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•Hybrid sodalite zeolites produced by in situ solvent-free synthesis.•Sodalite phase was obtained with high crystallinity without seed or template addition.•Solvent-free route seems to tend to form several nuclei of crystallization.•Only organosilanes with longer alkyl chains afforded hydrophobic characteristics.
Sol-gel technique aiming enzymatic immobilization in situ with ionic liquids as additives is poorly studied. In this process, the addition of the enzyme is carried out in the synthesis of the ...support. The characteristics of ionic liquids, such as low vapor pressure, thermal stability, and non-flammability, make them strong candidates for use as immobilization additives. The objective of the present study was to immobilize the
Candida antarctica
B lipase by the sol-gel technique using ionic liquids as additives. The optimum points determined for ionic liquids 1-butyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium bromide, and 1 hexadecyl-3-methylimimidazolium were 0.30, 0.27, and 0.22 g/mL of enzyme and 1.60, 1.52, and 1.52% of additive, respectively. The amount of enzyme and ionic liquids used in aerogel immobilization was the same as the optimized values in the xerogel immobilization process (for each ionic liquid). Ionic liquids proved to be good additives in the enzymatic immobilization process. Xerogel, regardless of the ionic liquid, presented a greater number of use cycles and better thermal stability compared to aerogel.
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