Green chemistry production of biopolymeric film-derived biomaterial prepared using natural alginate and vanillin compounds for application as a biocurative.

The present work presents the results obtained in the production of vanillin-doped alginate biopolymeric film using green chemistry methodology. Alginate dressings are already a therapeutic reality, but they act only by maintaining the appropriate environment for healing. In order to improve their properties, the incorporation of vanillin was proposed due to its antioxidant and antimicrobial potential. Different biopolymeric films were produced employing the experiment planning through response surface analysis, which allowed determining the best region for a medium value of solubility and high degree of swelling. This region refers to values above 0.07 g of CaCl2 and concentrations above 0.024 g of vanillin, triggering solubility between 25 and 30% and a degree of swelling above 100% and with fixed values of alginate (0.85 g). Such data are related to experiments (A), (B), and (C) listed in Table 1. Regarding the optimization of the process, the normal boundary intersection (NBI) method allowed the analysis of concave regions, predicting the optimal points and generating the Pareto chart with equidistant limits. The antimicrobial test allowed observing the antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa microorganisms from the biopolymeric films, as well as a solution of vanillin with calcium chloride and glycerol obtaining a halo of inhibition only in the presence of vanillin, and there was no significant difference between the results obtained in the experiments (A) and (B). The thermal analyses showed that the material has thermal stability in the ideal temperature range (~ 25 °C) for application as a biocurative. We preliminarily concluded that the alginate biopolymeric film doped with vanillin prepared using green chemical methodology presents antimicrobial properties and thermal stability that indicate its potential use as biocurative.

Use of brewer's residual yeast for production of bacterial nanocellulose with Gluconacetobacter hansenii.

Bacterial nanocellulose (BNC) has attained elevated interest due to its versatile structure and high resistance characteristics. Accordingly, efforts have been made in order to reduce its production costs, such as the employment of its by-products as a nutrient broth to yield the microorganism. Residual brewer's yeast is an excellent recourse, due to its high nutritional value and availability. Therefore, research which aimed to contribute to the development of a low cost, efficient and biosustainable technology for BNC production with Gluconacetobacter hansenii was carried out. BNC was obtained from residual brewer's yeast hydrolysate at pH 7.0 and five days of incubation at 30 °C in static culture. The hydrolysate was characterized by the amount of sugars, fatty acids, total proteins and ash content. Subsequently, BNC obtained was characterized in terms of yield, carbon conversion ratio, hydrodynamic size, crystallinity, morphology, Fourier-transform infrared spectroscopy, and surface analysis. Residual brewer's yeast hydrolysate proved to be efficient in BNC production via gluconeogenesis with consumption of alanine, threonine and glycerol, obtaining 1.9 times the yield of the chemically defined broth adopted as standard. Additionally, properties observed in the obtained BNC were equal to those obtained from conventional chemical medium. The research contributed to bacterial nanocellulose production using by-products from the brewing industry.

Cytotoxicity, structural, conformational, and techno-functional properties of α-lactalbumin nanostructured aggregates.

Protein nanostructures can be used in food applications to improve the techno-functional properties of a food formulation. This study aims to find the best conditions for the production and conformational change of α-lactalbumin nanostructured aggregates. The criteria to determine the best operating conditions to produce α-lactalbumin nanostructured aggregates were intensification of foaming and emulsification, techno-functional proprieties, cytotoxic, and antibacterial activity of nanostructures compared with native α-lactalbumin. Conformational alterations occurred in the α-helix and sheet-ß protein structures. The size obtained by dynamic light scattering was 163.84 nm with a polydispersity index of 0.29. The nano protein improved the techno-functional property compared to the native protein. Additionally, nanostructures had no cytotoxic effect and were innocuous to bacterial activity. Thus, this study presents the best conditions to produce α-lactalbumin nanostructured aggregates with improved properties that allow new food industry applications.

Influence of Homogenization in the Physicochemical Quality of Human Milk and Fat Retention in Gastric Tubes.

BACKGROUND: The retention of human milk nutrients in gastric tubes used to feed premature infants is a challenge to be overcome. RESEARCH AIMS: To evaluate (1) the performance of six homogenizers (mixing processor, piston valve, ultrasonic bath, ultraturrax, stirring mixer, and ultrasound probe) for the fat retention reduction in gastric tubes; (2) the influence of the best homogenization conditions on the fatty acid and protein profiles of human milk; and (3) the cost/benefit ratio for the inclusion of homogenization as a new step in human milk processing. METHODS: The influence of different levels and times of homogenization on reducing fat retention of human milk in probes was evaluated in this comparative prospective cross-sectional study. After homogenization, human milk flowed through a gavage and infusion pump apparatus used for feeding. Fat content was quantified before and after feeding. The techniques that reduced fat globule sizes and/or promoted a lower percentage of fat holding were evaluated for efficiency, variations in the fatty acid and protein profiles, and energy density and operating costs. RESULTS: Homogenization led to a reduction in fat retention in feeding probes. The mixer processor and the ultrasound probe reduced fat retention by 99.23% (SD = 0.07) and 99.95% (SD = 0.02), respectively, and did not negatively influence fatty acid and protein profiles. The mixer processor demonstrated low energy density and low cost for human milk processing. CONCLUSION: Homogenization promoted reduced fat retention in the feed probe and could help maintain fat nutrients of human milk during enteral feeding.

Nanostructured conjugates from tara gum and α-lactalbumin. Part 1. Structural characterization.

Nanostructures from conjugates of tara gum and α-lactalbumin were obtained via the heat-gelation process with pH adjustment. The conjugates were produced by Maillard reaction using the dry-heating method in lyophilized or spray-dried mixtures of TG and α-la and were characterized by browning index (BI) and percentage of free amino groups (% FAG). Nanostructured systems were characterized by dynamic light scattering, ζ-potential, circular dichroism, and intrinsic fluorescence to evaluate the structures. The most appropriate time of conjugation was 2 days. The spray-dried and lyophilized mixtures presented different values of BI and % FAG (p < 0.05), indicating that the glycosylation was more intense in lyophilized mixtures. Nanostructures with average sizes lower than 300 nm were formed under different conditions of temperature, pH, and heating time. Analyses of circular dichroism and intrinsic fluorescence showed conformational changes in the nanostructures, mainly a decrease in the α-helix content in spray-dried systems. The characteristics presented by the studied systems showed that it is possible to obtain nanostructures from conjugates of tara gum and α-lactalbumin.

Atividade antimicrobiana das nanoestruturas de fibroína de seda / Antimicrobial activity of silk fibroine nanoparticles

A segurança alimentar e nutricional são fatores que, atualmente, estão em crescente preocupação. Apesar da existência de práticas de higiene na manipulação e produção de alimentos, é necessário aplicar novas metodologias para redução de patologias causadas por contaminação alimentícia que ocorrem por diversas bactérias, que estão relacionados com as Doenças Veiculadas por Alimentos (DVAs). Em especial, temos a Escherichia coli, Enterobacter cloacae, Staphylococcus aureus e Salmonella typhi. O objetivo do trabalho foi de avaliar a atividade antimicrobiana das Nanoestruturas de Fibroína de Seda com tamanho médio de 250,7 ± 10,4 nm sobre as bactérias supracitadas. As concentrações de nanopartículas utilizadas não alcançaram a concentração inibitória mínima, necessitando de estudos posteriores para obter essa concentração.

Avaliação antimicrobiana de macroestrutura e nanoestruturas de carbonato de cálcio / Antimicrobial evaluation of macrostructures and nanostructures of calcium carbonate

A ocorrência de doenças transmitidas por alimentos se dá principalmente pelas bactérias Salmonella e E.coli. A Salmonella pode causar infecções generalizadas ao entrar na corrente sanguínea por meio das paredes do intestino e a E. coli produz toxinas que podem causar complicações. Uma solução é encontrada no uso da nanotecnologia que desperta o interesse dos cientistas em suas possíveis aplicações inovadoras nas indústrias. Esse trabalho estudou os efeitos antimicrobianos do Carbonato de Cálcio macro e nanoestruturado em E. Coli e Salmonella Typ. Para a nanoestrutura os melhores resultados foram com 1250 e 1875 µg.mL-1 em E. Coli e S. Typ. As concentração de 1000, 1500 e 1875 µg.mL-1 de macro CaCO3 mostraram-se mais eficientes para E. Coli e no caso da S. Typ 1000 e 1500 µg.mL-1. Para validar e tornar aplicável o uso de nano CaCO3 são sugeridos estudos toxicológicos e estudos com diferentes tamanhos do material nanoestruturado.

Avaliação antimicrobiana in vitro da nanoestrutura de óxido de zinco para posterior aplicação em embalagens / Antimicrobial evaluation in vitro of zinc oxide nanoestruture for subsequent application in packaging

A goiaba é uma das fruticulturas que se destaca no Brasil, por ser rica em nutrientes e ter elevada produção, porém há uma elevada perda/desperdício desse fruto pela sua alta perecibilidade. Logo, o objetivo deste estudo foi avaliar a atividade antimicrobiana das nanoestruturas de ZnO, a fim de aplicá-las em filmes de goma tara para preservação da goiaba. Foi feita a análise da curva de crescimento das bactérias Escherichia coli, Enterobacter cloacae, Salmonella typhimurium e Staphylococcus aureus na presença da nanoestrutura no leitor de microplaca. Estas apresentaram atividade antimicrobiana frente às bactérias, visto que houve o retardo do crescimento com o passar do tempo de análise. Verifica-se o potencial uso desta nanoestrutura para aumentar vida útil da goiaba.

Avaliação in vitro da atividade antimicrobiana de nanoestrutura de quitosana / In vitro avaliation of antimicrobial activity of chitosan nanostructure

A quitosana é um polímero capaz de apresentar atividade antimicrobiana e na sua forma nanoestruturada acredita-se que apresente maior desempenho. Portanto, este trabalho avaliou a capacidade antimicrobiana da nanoquitosana via diluições em microplaca. Utilizou-se quatro bactérias Escherichia coli, Enterobacter cloacae, Salmonella sp. e Staphylococus aureus em diferentes concentrações de nanoestrutura. Observou que em todas as concentrações (0,26 µg ml-1 a 19,7 µg ml-1) houve inibição, além disso, percebeu-se uma constância na absorção ao longo do tempo para algumas concentrações, indicando possível atividade bacteriostática da nanoestrutura. Assim, a nanoestrutura de quitosana apresentou atividade antimicrobiana, com ação bacteriocida e bacterioestática sobre os microrganismos estudados.

Filme de goma tara com nanoestrutura de ZnO para preservação de fruto pós-colheita / Tare gum film with ZnO nanostructures for preservation of postharvest fruit

O Brasil é o 3º maior produtor mundial de frutas, porém as perdas/desperdícios no pós-colheita podem chegar até 30 %, principalmente, pelo metabolismo do fruto e fitopatógenos. A nanotecnologia surge, então, como alternativa para mitigar esse problema, sendo o setor de embalagens o mais promissor. Assim, o objetivo deste trabalho foi obter e caracterizar de filmes de goma Tara com nanoestruturas de óxido de zinco (ZnO) com atividades antimicrobianas. O filme obteve espessuras entre 0,04957 e 0,36380 mm, sendo o filme com 5% (m/v) de nanoestrutura de ZnO com maior espessura. A porcentagem de solubilidade dos filmes de nanoestruturas de ZnO foi mais elevada que o filme sem nanoestrutura. O teor de umidade variou de 32,5592 a 10,9658 % entre os filmes e à medida que a concentração de nanoestrutura aumentou houve aumento da permeabilidade.

Obtenção e caracterização de filmes de Goma Tara incorporados com Nanopartículas de Prata para proteção de frutos / Obtention and characterization of tare gum films incorporated with silver nanoparticles to fruits protection

Tendo em vista que a escassez e a perda/desperdício de alimentos é uma realidade crescente devido as falhas em toda a logística de produção e pós colheita, a nanotecnologia em embalagens apresenta-se, nos últimos anos, como uma alternativa para solucionar alguns desses problemas. Portanto, este trabalho visa analisar as propriedades dos filmes de Goma Tara com Nanopartículas de Prata (AgNP) para futura aplicação em frutos. Os filmes produzidos neste trabalho, em especial aqueles com maior concentração de AgNP, apresentaram uma espessura ideal (entre 0,0457 e 0,0570mm), maiores valores de gramatura (52,53 g.m-2), alta solubilidade (cerca de 98%), menores teores de umidade (36,35%) e maior retenção de transferência de vapor d’água, cerca de 800 g.μm.m-2.dia-1.mmHg-1, comprovando sua eficiência como embalagem para conservação de alimentos.

Avaliação antimicrobiana da nanoquitosana incorporada no hidrogel de PVA e propilenoglicol / Antimicrobial evaluation of PVA and propylene glycol hydrogel integrated nanochitosan

A nanoquitosana (NQ) possui potencial antimicrobiano contra microrganismos causadores de Doenças Transmitidas por Alimentos. Este trabalho busca determinar o efeito antimicrobiano da NQ em hidrogéis para substituir os produtos assépticos e sanitizantes convencionais. O hidrogel de propilenoglicol foi testado em superfície de aço inox em E. coli, apresentando crescimento de 303±53 UFC, inferior ao controle 481,5±62,5 UFC. O gel de PVA foi testado pelo método de disco-difusão contra E. coli, com halo de inibição de 2,7±0,2 cm (NQ 71,43 µg.mL-1) e 2,3±0,3 cm (NQ 142,85 µg.mL-1), e S. typ, com halo de inibição de 3,0±0,2 cm e 2,8±0,2 cm, com NQ 71,43 µg.mL-1 e 142,85 µg.mL-1, respectivamente. Os resultados indicam potencial uso da NQ em produtos sanitizantes, para isso são necessários testes toxicológicos e caracterização das nanoestruturas.

Avaliação antimicrobiana de hidrogel de PVA e gel de Propilenoglicol incorporado com Nanopartículas de Prata como sanitizantes / Antimicrobial evaluation of PVA hydrogel and propilene glycol incorporated with silver nanoparticles

As Doenças Transmitidas por Alimentos causam diversos problemas de saúde e prejuízos econômicos e tem como principal causa a má manipulação dos alimentos. Portanto, é necessário o uso de estratégias de higiene pessoal e de sanitização das instalações e equipamentos. Pensando nisso, este trabalho apresenta a síntese e análise antimicrobiana por disco-difusão e contagem bacteriana de um gel sanitizante a base de Polietileno Glicol e um hidrogel de PVA com a incorporação de Nanopartículas de Prata (AgNP). Para o primeiro gel, com AgNP, o resultado foi quatro vezes maior que o controle. Para o segundo gel, o aumento na concentração de AgNP garantiu uma maior inibição bacteriana. Os resultados obtidos comprovam a potencialidade deste sanitizante para aplicação industrial, comercial e laboratorial.

Hidrogeis de polivinil-álcool (PVA) contendo o bacteriófago UFV-AREG1 para aplicação como curativo adesivo para a indústria de alimentos / Polyvinyl-alcohol (PVA) hydrogel containing the UFV-AREG1 bacteriophagus for application as a curative adhesive for the food industry

Infecções cutâneas obtidas por cortes nas mãos de manipuladores podem gerar contaminação nos alimentos. O objetivo deste trabalho foi incorporar o bacteriófago UFV-AREG1 em hidrogel de álcool poli(vinílico) – PVA, aplicando-o futuramente como curativo adesivo. Foi adicionado 1,0 mL de solução do fago no PVA e seco em estufa por 48 h. Após, os hidrogeis foram submetidos a testes de Intumescimento, Espectroscopia no infravermelho (FTIR) e efeito antimicrobiano sobre E. coli O157:H7. O intumescimento do PVA-fago foi maior que o PVA-controle (p<0,05). A área de inibição do PVA-fago foi de 3,715 cm2 contra 2,916 cm2 do controle. As análises do FTIR mostraram um pico para o PVA-fago não encontrado no PVA-controle. Foi possível incorporar o bacteriófago em hidrogel de PVA e avaliar sua liberação para posterior aplicação como curativo adesivo.

Acacia gum as modifier of thermal stability, solubility and emulsifying properties of α-lactalbumin.

Protein-polysaccharide conjugates often display improved techno-functional properties when compared to their individual involved biomolecules. α-Lactalbumin:acacia gum (α-la:AG) conjugates were prepared via Maillard reaction by the dry-heating method. Conjugate formation was confirmed using results of absorbance, o-phthalaldehyde test, sodium dodecyl sulfate-polyacrilamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography. Techno-functional properties (emulsifying characteristics, solubility, and thermal stability) were evaluated for α-la, α-la/AG mixtures and α-la:AG conjugates. Conjugate thermal stability was improved compared to pure α-la treated at the same conditions of conjugate formation. Response surface methodology was used to establish models to predict solubility and emulsifying activity as functions of the salt concentration, pH and reaction time. α-la:AG conjugate solubility is affected in a complex manner by the three factors analyzed. Emulsifying activity index (EAI) of α-la is significantly affected by pH, while the α-la:AG EAI is affected by the three analyzed factors. Both solubility and EAI are maximized with pH 8.0, NaCl concentration of 0.3 mol L(-1) and two days of Maillard reaction.

Production, characterization and foamability of α-lactalbumin/glycomacropeptide supramolecular structures.

The study of protein interactions has generated great interest in the food industry. Therefore, research on new supramolecular structures shows promise. Supramolecular structures of the whey proteins α-lactalbumin and glycomacropeptide were produced under varying heat treatments (25 to 75°C) and acidic conditions (pH3.5 to 6.5). Isothermal titration calorimetry experiments showed protein interactions and demonstrated that this is an enthalpically driven process. Supramolecular protein structures in aqueous solutions were characterized by circular dichroism and intrinsic fluorescence spectroscopy. Additional photon correlation spectroscopy experiments showed that the size distribution of the structures ranged from 4 to 3545nm among the different conditions. At higher temperatures, lower pH increased particle size. The foamability of the supramolecular protein structures was evaluated. Analysis of variance and analysis of regression for foaming properties indicated that the two-factor interactions between pH and temperature exhibited a significant effect on the volume and stability of the foam.

Copper recovery from ore by liquid-liquid extraction using aqueous two-phase system.

We investigated the extraction behavior of Cu(II) in the aqueous two-phase system (ATPS) formed by (L35+MgSO(4)+H(2)O) or (L35+(NH(4))(2)SO(4)+H(2)O) in the presence of the extracting agent 1-(2-pyridylazo)-2-naphthol (PAN). At pH=3 and a PAN concentration of 0.285 mmol kg(-1), both ATPS lead to the effective separation of Cu(II) from other metallic ions (Zn(II), Co(II), Ni(II) and Fe(III)). High separation factors range between 1000 and 10,000 were obtained for the extraction of Cu(II) and concomitant metallic ions. This ATPS was used for the extraction of Cu(II) from a leached ore concentrate with a extraction percentage of 90.4 ± 1.1%; other metals were mainly located in the bottom phase.

Microcalorimetric and SAXS determination of PEO-SDS interactions: the effect of cosolutes formed by ions.

The effect of different ionic cosolutes (NaCl, Na(2)SO(4), Li(2)SO(4), NaSCN, Na(2)[Fe(CN)(5)NO], and Na(3)[Co(NO)(6)]) on the interaction between sodium dodecyl sulfate (SDS) and poly(ethylene oxide) (PEO) was examined by small-angle X-ray scattering (SAXS) and isothermal titration calorimetric techniques. The critical aggregation concentration values (cac), the saturation concentration (C(2)), the integral enthalpy change for aggregate formation (ΔH(agg)(int)) and the standard free energy change of micelle adsorption on the macromolecule chain (ΔΔG(agg)) were derived from the calorimetric titration curves. In the presence of 1.00 mmol L(-1) cosolute, no changes in the parameters were observed when compared with those obtained for SDS-PEO interactions in pure water. For NaCl, Na(2)SO(4), Li(2)SO(4), and NaSCN at 10.0 and 100 mmol L(-1), the cosolute presence lowered cac, increased C(2), and the PEO-SDS aggregate became more stable. In the presence of Na(2)[Fe(CN)(5)NO], the calorimetric titration curves changed drastically, showing a possible reduction in the PEO-SDS degree of interaction, possibility disrupting the formed nanostructure; however, the SAXS data confirmed, independent of the small energy observed, the presence of aggregates adsorbed on the polymer chain.