Carboxymethyl cellulose/lignin blended films: physicochemical and antioxidant properties

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Carboxymethyl cellulose-based films: Effect of organosolv lignin incorporation on physicochemical and antioxidant properties

Organosolv lignin was incorporated in carboxymethyl cellulose (CMC)-based films as a reinforcing and bioactive agent. Films were produced by the casting method using compatible and environmentally friendly solvents. The incorporation of lignin in CMC-based films was evaluated in term of morphology, physicochemical, barrier, mechanical and antioxidant properties. Solubility tests showed that lignin improved the water resistance of the films for approx. 60%. This behavior was also observed for the water vapor permeability, achieving a 20% reduction. Morphological characteristics suggested low compatibility between organosolv lignin and CMC matrix, revealed by the small aggregates homogeneously distributed in the film, through scanning electron microscopy, related to the self-assembly behavior of lignin. CMC/lignin-based films also presented higher thermal stability. Fourier transform infrared spectroscopy showed that incorporation of lignin led to small changes in the film's structure. Finally, organosolv lignin proved to be a promising material for the development of active CMC-based films due to its demonstrated antioxidant activity that can be useful to pack food products that suffer from undesirable oxidation reactions.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Nanospraydryer for the production of sub-micro particles based on bovine lactoferrin

This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469 unit and COMPETE 2020 (POCI-01-0145- FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Arlete M. Marques (SFRH/BD/132911/2017) is the recipient of a fellowship from Fundação para a Ciência e Tecnologia (FCT, Portugal)info:eu-repo/semantics/publishedVersio

Ultrasonication processing for the production of plant-based nanoemulsions

Plant-derived proteins have been emerging and growing in interest over the past few years, due to their interesting properties and the trend to replace animal-derived proteins [1]. Ultrasonication processing can be used to develop nanoemulsions based on plant proteins that are kinetically stabilized by their small dimension, unlike classic emulsions [2]. In this work, oil-in-water nanoemulsions were produced through high-speed homogenization, followed by ultrasonic homogenization (US), using different plant-derived proteins, including potato (Solanum tuberosum), lupin (Lupinus angustifolius), pea (Pisum sativum), chickpea (Cicer arietinum) and faba bean (Vicia faba) protein as emulsifiers. A central composite rotatable experimental design was used to evaluate the influence of three independent variables: water/oil ratio (65-75% of water), protein content (1-6%) and US time (1-7 min) on the size average (by intensity) and polydispersity index (PDI) of the nanoemulsions. A total of 17 experiments were performed with 14 three-level experimental points, and 3 replicates at the central point. The effect of the US time (0, 3, 4.5 and 6 min) in the potato and lupin proteins primary and secondary structures were analysed through SDS-PAGE electrophoresis and circular dichroism, respectively. Results showed that the use of potato, lupin and pea proteins lead to the formation of stable nanoemulsions, while chickpea and faba bean proteins resulted in non-stable nanoemulsions, with phase separation. The smallest mean droplet size for potato protein was 439.9 nm and PDI value 0.464 [21:73 (w/w) oil/water ratio, 6% of protein and 6 min of US]. The smallest mean droplet size for lupin protein was 505.5 nm and PDI value 0.434, and for pea protein the droplet size was 551.3 nm and PDI value 0.249 [23.6:73 (w/w) oil/water ratio, 3.4% of protein and 6 min of US]. Electrophoresis results show that for native potato and lupin samples the ultrasonication did not induce significant changes in the protein pattern, indicating that the US treatment did not modify the primary structure. Regarding the second structure, US did not change the secondary structure of potato protein but induced a slight increase of -helix for all US treatments for lupin protein. Stable nanoemulsions can be developed using plant-derived proteins and ultrasonication, foreseeing different applications in the food industry.This study was supported by the project cLabel+ (POCI-01-0247-FEDER-046080) cofinanced by Compete 2020, Lisbon 2020, Portugal 2020 and the European Union, through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

OS TRÊS PROBLEMAS GREGOS DA ANTIGUIDADE, AS CONSTRUÇÕES COM RÉGUA E COMPASSO E A TEORIA DE GALOIS

Este artigo foi pensado para alunos do Curso de Matemática. Os assuntos que constituem o titulo tripartido acima se reencontram ao longo da História, do século V antes de Cristo até o século XX. O texto mostra, utilizando a teoria de Galois, que é impossível resolver, com uso exclusivo de régua e compasso, os três problemas gregos da antiguidade: a quadratura do circulo, a duplicação do cubo e a trisecção do ângulo

O BANQUETE DE HILBERT OU UM DIÁLOGO SOBRE O INFINITO

Este artigo versa sobre a história do encontro de Sócrates e Gödel em uma das ruas do céu, Sócrates solicita a Gödel as mais recentes informações sobre o progresso da Matemática no século XX. Gödel lhe informa que está vindo de um banquete oferecido por Hilbert a matemáticos e lógicos. O objetivo de Hilbert, matemático alemão que morreu aos 81 anos, em 1943, era discutir o problema do infinito através dos tempos, começando com Tales de Mileto, no século IV A.C até a segunda metade do século XX com Gödel. A partir do local de encontro, começa um diálogo entre as duas personagens, sobre tudo o que se passou no banquete de Hilbert

O MÉTODO AXIOMÁTICO E O PROBLEMA DA CONSISTÊNCIA ABSOLUTA

Este artigo foi escrito especialmente para aqueles iniciados em Matemática que se interessam por Lógica, Filosofia e História da Matemática. A metodologia escolhida foi a do diálogo  entre  Sócrates (século IV a.C.) e Gödel (1906-1978),  em local previamente  marcado - no céu - onde a contemporaneidade é absoluta,  pois passado  e futuro  se fundem. Sabendo, durante uma diversificada  conversa com Hilbert (1862- 1943), que o   método   axiomático   foi   exaustivamente  explorado   nos   sécu- los XIX e XX e que, através dele, os matemáticos conseguiram (ou quase conseguiram)  a síntese do   pensamento   matemático,  Sócrates   propõe-lhe que o deixe atualizado sobre tais coisas, pois, como filósofo,   tem   neces- sidade de conhecer   a   evolução   das   teorias   científicas.   Hilbert   recomen- da a Sócrates   procurar Gödel    que, em 1931,    com apenas    25 anos, publicou um trabalho revolucionário sobre o assunto, abalando os fun- damentos não só da Matemática, mas, também, da Lógica, mexendo, conseqüentemente com a Filosofia

Boletim da Sociedade Brasileira de Matemática

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Lactoferrin as a carrier of iron: Development and physicochemical characterization

Iron deficiency is the main cause of anemia, one of the most common nutritional deficiencies affecting millions of people worldwide. In addition, iron instability, sensitivity, and intense flavor limit its use in food fortification. In this work, lactoferrin (LF) particles were developed by Nano Spray Dryer (NSD) and its capacity to be used as an iron carrier was evaluated. The effect of NSD temperature (60°C, 80°C, and 100°C) and LF concentrations (10mgmL1, 50mgmL1, and 100mgmL1) was evaluated on the LF structure and on the production and stability of a LF-iron carrier. Results showed that the NSD is suitable for producing LF particles with diameters ranged from 38.8nm to 4533.6nm. Although different surface morphologies were obtained, higher protein concentrations (100mgmL1) produced round shape and smooth surface particles, but for lower protein concentrations (10mgmL1 and 50mgmL1) wrinkled particles and doughnut shape particles were obtained. SDS-page electrophoresis and circular dichroism (CD) for secondary structure (185260nm) show that the characteristics of the structures were maintained, meaning that NSD does not cause protein degradation. CD for tertiary structure (250nm350nm) and fluorescence tests confirmed the interaction between LF and iron, observed by an intensity decrease and a wavelength shift in fluorescence spectra. The CD tertiary structure analysis showed higher ellipticity for the Trp peak, meaning conformational changes in the neighbor amino acids due to protein-iron interaction. Iron release experiments were performed at different pH values (2.0 and 7.4) at 37°C aiming to understand the release mechanism in different media. Results showed that at pH 2 the iron release could be described by the linear superposition model (Radj2=0.9879) (explained by Fick and relaxation phenomenon) and that at pH 7.4 there is no iron release, showing that particles are stable at neutral pH. NSD is a suitable technology for producing iron-loaded protein-based carriers that could be used in food applications.INL -Idaho National Laboratory(2020.03447)info:eu-repo/semantics/publishedVersio