Partitioning of glycomacropeptide in aqueous two-phase systems

The partition behavior of glycomacropeptide (GMP) was determined in polyethylene glycol (PEG) and sodium citrate aqueous two-phase systems (ATPS). It was found that the partitioning of GMP depends on PEG molar mass, tie line length, pH, NaCl concentration and temperature. The obtained data indicates that GMP is preferentially partitioned into the PEG phase without addition of NaCl at pH 8.0. Larger tie line lengths and higher temperatures favor GMP partition to the PEG phase. Furthermore, it was verified that PEG molar mass and concentration have a slight effect on GMP partition. The increase in the molar mass of PEG induces a reduction of the protein solubility in the top PEG rich phase, being shown that the use of PEG1500 is beneficial for the extraction of GMP. A protein recovery higher than 85% was obtained in the top phase of these systems, clearly demonstrating its suitability as a starting point for the separation of GMP.Research Support Foundation of Minas Gerais (FAPEMIG)National Council of Technological and Scientific Development (CNPq

Kinetics and Thermodynamics of Oil Extraction from Jatropha curcas

In the study the yield and kinetic and thermodynamic parameters of the oil extraction process from Jatropha curcas L. using ethanol as a solvent were evaluated for different temperatures, moisture contents of the solid phase, and particle sizes. The extraction process yield increased with contact time of solid particles with the solvent until reaching equilibrium (saturation of the solvent), for all the temperatures, moisture contents, and average particle sizes. These parameters significantly influenced (95% confidence) the extracted oil yield. A convective mass transfer model was used to simulate the extraction process and estimate the kinetic and thermodynamic parameters. For all conditions evaluated, values of oil yield in the liquid phase close to equilibrium were obtained in approximately 20 min. The variations of enthalpy and entropy were positive, indicating that the process is endothermic and irreversible. Values obtained for the variation in Gibbs free energy showed that the extraction process using ethanol as a solvent is spontaneous and thermodynamically favorable for the moisture content of 0%, where the smaller the average particle size the greater the spontaneity of the process

Density, refractive index, apparent specific volume, and electrical conductivity of aqueous solutions of poly(ethylene glycol) 1500 at different temperatures

Thermophysical properties of aqueous solutions of poly(ethylene glycol) 1500 g·mol–1 were measured as a function of polymer concentration w=(0.05, 0.10, 0.15, 0.20 and 0.25) and temperature T/K=(288, 293, 298, 303 and 308). Aqueous systems composed of poly(ethylene glycol) are frequently used in processes involving the separation of biological compounds. The density of the solutions varied from (1001.68 to 1042.65) kg·m–3, the refractive index ranged from (1.3377 to 1.3681), the apparent specific volume was between (0.8336 and 0.8528) g·cm–3, and the electrical conductivity varied between (66.22 and 170.29) 10–3 mS·cm–1. Polynomial models for the properties as a function of temperature and poly(ethylene glycol) 1500 g·mol–1 concentration were fitted to the experimental data. Models accounting for combined effects between variables are particularly useful in industrial applications in which physical parameters must be promptly and accurately calculated.We are thankful to the Brazilian agencies CAPES, CNPq, FAPEMIG, and FAPESP for the financial support, fellowships, and grants

Máscara facial artesanal pode ser esterilizada sem comprometer sua eficácia

Background and Objectives: COVID-19 caused by SARS-CoV-2 is transmitted by contact, droplets and aerosols. The World Health Organization recommends the mandatory use of surgical masks for health professionals and encourages countries to adhere to their use, en masse, in order to minimize the transmission of the virus. Since the lack of this personal protective equipment is a cause for concern, the objective of this study was to evaluate the characteristics of facial masks regarding (i) the mechanical properties of elongation, rupture stress and resistance to air passage and (ii) the morphometric properties of thickness, fiber diameter and pore distribution after autoclave sterilization. Methods: The masks were made in TNT Spunbonded (100% polypropylene, 60 g/m2), autoclaved at 70 ºC for 5 minutes and stored in plastic films at room temperature. Then, the mechanical properties were determined in an Instron universal testing machine and Gurley type automatic densimeter and the morphometric properties in a semi-automatic thickness gauge and scanning electron microscope. Results: It was observed that a cycle of sterilization of facial masks, by moist heat under pressure, increased the blanket's stiffness, did not produce physical damage and did not reduce the blanket's barrier capacity. Conclusion: The sterilization of face masks made of TNT can be considered a strategy to increase safety in their production and use.Antecedentes y objetivos: El COVID-19 causado por el SARS-CoV-2 se transmite por contacto, gotitas y aerosoles. La Organización Mundial de la Salud recomienda el uso obligatorio de mascarillas quirúrgicas para los profesionales de la salud y alienta a los países a adherirse a su uso, en masa, con el fin de minimizar la transmisión del virus. Dado que la falta de este equipo de protección personal es motivo de preocupación, el objetivo de este estudio fue evaluar las características de las máscaras faciales en cuanto a (i) las propiedades mecánicas de elongación, tensión de rotura y resistencia al paso del aire y (ii) la morfometría propiedades de espesor, diámetro de fibra y distribución de poros después de la esterilización en autoclave. Métodos: Las máscaras se fabricaron en TNT Spunbonded (100% polipropileno, 60 g / m2), se esterilizaron en autoclave a 70 ºC durante 5 minutos y se almacenaron en películas plásticas a temperatura ambiente. Posteriormente, se determinaron las propiedades mecánicas en una máquina de ensayo universal Instron y densímetro automático tipo Gurley y las propiedades morfométricas en un medidor de espesor semiautomático y microscópio electrónico escaneando.Resultados: Se observó que un ciclo de esterilización de mascarillas faciales, por calor húmedo a presión, incrementó la rigidez de la manta, no produjo daño físico y no redujo la capacidad barrera de la manta. Conclusión: La esterilización de mascarillas faciales fabricadas con TNT puede considerarse una estrategia para aumentar la seguridad en su producción y uso.Justificativa e Objetivos: A COVID-19 causada pelo SARS-CoV-2 é transmitida pelo contato, por gotículas e por aerossóis. A Organização Mundial da Saúde recomenda a obrigatoriedade do uso de máscaras cirúrgicas aos profissionais da saúde e incentiva os países a aderirem ao seu uso, em massa, a fim de minimizar a transmissibilidade do vírus. Posto que a falta desse equipamento de proteção individual causa preocupação, o objetivo deste trabalho foi avaliar as características de máscaras faciais quanto (i) às propriedades mecânicas alongamento, tensão de ruptura e resistência a passagem de ar e (ii) às propriedades morfométricas espessura, diâmetro das fibras e distribuição de poros após esterilização em autoclave. Métodos: As máscaras foram confeccionadas em TNT Spunbonded (100% polipropileno, 60 g/m2), autoclavadas a 70 ºC por 5 minutos e armazendadas em filmes plásticos a temperatura ambiente. Na sequência, as propriedades mecânicas foram determinadas em máquina de teste universal Instron e densímetro automático tipo Gurley e as propriedades morfométricas em medidor de espessura semiautomático e microscópio eletrônico de varredura. Resultados: Observou-se que um ciclo de esterilização das máscaras faciais, por calor úmido sob pressão, promoveu o aumento da rigidez da manta, não produziu danos físicos e não diminuiu a capacidade de barreira da manta. Conclusão: A esterilização de máscaras faciais confeccionadas em TNT pode ser considerada uma estratégia para aumentar a segurança na sua produção e uso

AVALIAÇÃO SENSORIAL E MAPA DE PREFERÊNCIA INTERNO DE MARCAS COMERCIAIS DE REFRIGERANTE SABOR GUARANÁ

O objetivo deste trabalho foi comparar sensorialmente sete marcas de refrigerante sabor guaraná, sendo seis produzidas por pequenas empresas e uma por empresa líder de mercado. A Análise Descritiva Quantitativa (ADQ) foi utilizada para descrever e quantificar os atributos sensoriais das amostras. A aceitabilidade sensorial das marcas de refrigerante foi determinada mediante escala hedônica e os resultados avaliados pela Análise de Componentes Principais, Mapa de Preferência Interno e ANOVA. A maioria dos consumidores preferiu o refrigerante da marca líder de mercado, que apresentou os atributos sabor e aroma característico em maior intensidade e sabor e aroma tutti-fruti em menor intensidade

Nanoencapsulation of quercetin into bio-based nanostructures obtained from assembling of α-lactalbumin and lysozyme

Nanotechnology possesses an intrinsic potential to produce new food ingredients and innovative products, with considerable benefits to human health. This can be attained via development of innovative structures for application in functional foods. In recent years, consumption of foods providing health benefits has risen chiefly as a result of significant investments from the food industry and widening consumer awareness in this field. Polyphenols constitute one such functional ingredient: it entails a large group of plant metabolites with a large spectrum of recognized biological activities in humans. Quercetin is, in particular, one of the most representative compounds of the flavonoid family; it has been assigned a wide range of health benefits, including anti-inflammatory agent, cancer prevention, DNA protection agent, antioxidant and cardio-protective agent. However, its bioavailability is low, so limited biological effects may be noticed arising from its poor solubility, gastrointestinal instability and low uptake rate through the gastrointestinal tract. A possible solution to overcome such limitations is nanoencapsulation of quercetin. Therefore, our study was aimed at encapsulating quercetin into bio-based nanostructures obtained from assembling of α-lactalbumin (α-La) and lysozyme (Lys), as promoted by heating at 75 oC for 15 min, at pH 11; evaluation of their association efficiency was performed. Such nanostructures were prepared via solubilization of 2 mg mL-1 of Lys and α-La powders in water, at a molar ratio of 1:0.54, and were extensively characterized by dynamic light scattering (for particle size, polydispersity and zeta potential) and transmission electron microscopy (for microstructure and morphology). Quercetin has been successfully encapsulated into protein nanostructures above 50% efficiency. These nanostructures exhibited spherical morphology, with average size below 100 nm and zeta potential around -35 mV. Our results suggest that quercetin encapsulated in such proteinaceous nanostructures may be used for manufacture of functional foods

Nanoemulsions of β-carotene using a high-energy emulsification-evaporation technique

Nanoemulsions of β-carotene were prepared using a high-energy emulsification-evaporation technique based on a 23 level factorial design. Results show that it is possible to obtain dispersions at a nanoscale range. Process parameters such as time and shear rate of homogenization affected significantly particle size distribution in terms of volume-weighted mean diameter and surface-weighted mean diameter. The obtained nanoemulsions presented a volume-surface diameter ranging from 9 to 280 nm immediately after the production of particles, displaying in all cases a monomodal size distribution. Those nanoemulsions showed a good physical stability during 21 days storage. The stability was evaluated by the maintenance of size distribution. However, β-carotene retention inside the micelles and color were affected by storage. Processing conditions also influenced storage stability.Fundação para a Ciência e a Tecnologia (FCT)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brasil)Conselho Nacional de Ciência e Tecnologia (CNPq, Brasil

Partitioning of bovine lactoferrin in aqueous two-phase system containing poly(ethylene glycol) and sodium citrate

The partitioning of the whey protein lactoferrin, which is an iron transporter glycoprotein, in an aqueous two-phase system composed of poly(ethylene glycol) (PEG) and sodium citrate was evaluated. Equilibrium data at 25 °C were determined for each system studied using PEG with a molar mass of 1000 and 4000 g·mol1 at pH values of 5.5, 6.5, and 7.5. An increase in the molar mass of the polymer promoted the expansion of the two-phase region and caused the migration of the lactoferrin to the salt-rich bottom phase. An increase in pH also led to the expansion of the biphasic region. However, changing the pH over the tested range slightly affected protein partitioning. Lactoferrin recovery percentages greater than 94% were observed for all of the systems evaluated. The results indicated that lactoferrin can be successfully partitioned in an aqueous two-phase system formed of 14% (w/w) PEG and 10% (w/w) sodium citrate at pH 5.5 and 25 °C. The protein was concentrated 1000-fold in the salt-rich bottom phase in this system.Brazilian agencies FAPESB,CNPq, and FAPEMIG for their financial suppor

Design of nanostructures, obtained from assembling of α-lactalbumin and lysozyme upon heat treatment and selective environmental conditions

Protein assembly into supramolecular structures (e.g. aggregates, fibrils and nanotubes) is a widespread phenomenon in biological sciences. Nowadays, it is well documented that the amphiphilic properties of proteins is a driving force to their self-assembling into innovative micro- and nanostructures of high interest in the food and pharmaceutical fields. Formation of such structures is strongly dependent on physicochemical conditions and protein conformation. In this study, bio-based nanostructures were produced from assembly of hen egg white lysozyme (Lys) and bovine α-lactalbumin (α-La) – i.e. two homologous globular proteins with opposite charge), under various processing conditions: heating treatment (55 °C and 75 °C), holding time (25 and 35 min) and pH (3 and 11). The nano-scale structures prepared by solubilization of 2 mg mL-1 of Lys and α-La powders in water, at a molar ratio of 1:0.54, were characterized via dynamic light scattering (in terms of particle size, polydispersity and zeta potential), and further analyzed by transmission electron microscopy (TEM). Smaller sized particles (75 nm) and low podydispersity values (0.24) were produced at pH 11 after heating at 75 °C for 25 min, whereas at pH 3 (and similar conditions) the average mean particle size was ca. 402 nm with polydispersity of 0.45. The nanostructure stability was also assessed; higher stability was obtained at pH 11 than 3, with zeta potentials of -35 and +27 mV, respectively, by 60 d. The nanostructure entities prepared at pH 11 were shown by TEM to possess a well defined spherical shape. Protein assembly mechanisms and intermolecular interactions involved appear to be controlled by the environmental conditions applied; therefore, an understanding of the quantitative effects of these conditions are crucial for rational design of new protein assemblies with tailor-made functionalities

Bioseparation processes

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