Search

Recently, plant derived proteins have increased in interest and use due to a combination of interesting properties and industry-wide trends to replace animal derived proteins. Electrohydrodynamic processing (EHDP), can be used to develop micro- and nanostructures of plant proteins in a facile manner and, thus, increase their opportunities in the food, pharmaceutical, and biomedical industries. One of the most currently studied and promising plant proteins is zein. This review covers the most studied strategies to produce electrospun and electrosprayed zein-based structures. The most relevant properties, such as size, morphology, and surface area, are discussed according to the potential areas of interest, for instance in the food, biomedical, and pharmaceutical industries. In addition, applications of other electrospun/electrosprayed plant derived proteins are also presented, confirming the increasing interest of different industries in alternative proteins which can help promote sustainability., Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of the UIDB/04469/2020 unit and by the I&D&I AgriFood XXI project, operation number NORTE-01-0145-FEDER-000041, cofinanced by the European Regional Development Fund (FEDER) under the scope of NORTE 2020 (Programa Operacional Regional do Norte 2014/2020). 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). Pedro Silva is the recipient of a fellowship (SFRD/BD/130247/2017) supported by Fundação para a Ciência e a Tecnologia, (FCT, Portugal). S. Torres-Giner acknowledges Spanish Ministry of Science and Innovation (MICI) for the funding received during his Ramón y Cajal contract (RYC2019-027784-I), info:eu-repo/semantics/publishedVersion

[Excerpt] In this work, different multilayer structures, using a polyhydroxybutyrate-co-valerate film with a valerate content of 8% (PHBV8) as support, were developed aiming the development of active bio-based multilayer systems. An interlayer based on zein nanofibers with and without cinnamaldehyde were electrospun in the PHBV8 film and three multilayer systems were developed: 1) without an outer layer; 2) using a PHBV8 film as outer layer; and 3) using an alginate-based film as outer layer. Their physico-chemical properties were evaluated through: water vapour and oxygen permeabilities and colour measurements, Fourier Transform Infrared Spectroscopy (FTIR) and thermal analyses. Results showed that the presence of different outer layers affected the water vapour permeability and transparency of the multilayer films. (...)

[Excerpt] Cupuassu (Theobroma grandiflorum), tucumã (Astrocaryum aculeatum), peach palm (Bactris gasipaes) and abricó (American Mammea L.) are exotic fruits found in the Brazilian Amazon rainforest. All of them are well known by the native populations, and for centuries the pulps have been used in the production of juices, deserts, jams, syrups, and alcoholic beverages, among others. Additionally, the fruit seeds have been used as animal feed, fertilizers or to plant new seedlings, but a great part of these seeds are usually discarded. (...)

Polyelectrolyte multilayer coatings have become a new and general way to functionalize and modify surfaces of various materials to change their interfacial properties, lead the sequential adsorption of polyelectrolytes of opposite charges to the formation of multilayer nanostructures. Sodium alginate, carragennan, chitosan, and two galactomannans were characterized in terms of their zeta potential (Zp) and hydrodynamic diameter (Z-average) (measured by dynamic light scattering), based on a 2^3 full factorial design, were the polysaccharides concentrations ranged from 0.2 % to 0.6 %, pH ranged from 3 to 7 and salt (NaCl) concentration ranged from 0 to 0.1 %, being the most influent parameters determined by Pareto charts. In the sodium alginate solution the Zp ranged from -50.5 to -84.7 mV and the Z-average varied between 765 and 3330 nm; in the carragennan solution the Zp ranged from -24.1 to -83.5 mV and the Z-average varied between 432 and 1400 nm; in both cases, the concentrations of polysaccharide and NaCl were the most influent parameters. For the chitosan solution, the values of the Zp ranged from 64.5 to 31.2 mV and the Z-average varied from 236 to 5500 nm; the main influencing parameters were the concentration of chitosan and the pH. For the galactomannan solutions the Zp ranged from -13.1 to -1.94 mV and from -14.3 to -2.70 mV, and the Z-average varied from 3230 to 41400 nm and from 2010 to 8540 nm for G. triacanthos and C. pulcherrima,respectively; the concentrations of NaCl and galactomannan showed to be the most influencing parameters. This work provides information regarding important polyelectrolyte properties and how these properties can be controlled by changing the polysaccharide concentration, pH and salt concentration, important to control the structure and texture of manufactured products in view of their potential application in the food, pharmaceutical, and cosmetic industries., info:eu-repo/semantics/publishedVersion

Dissertação de mestrado em Biotecnologia, Over time, in developed countries, people have become more concerned about the safety of the food they eat, and so, there has been a growing demand for convenience products, followed by fresh-cut fruits and vegetables. Unhygienic practices in preparation of fresh-cut products may pose risks to public health by causing foodborne illnesses, due to microbial contamination. Many of the outbreaks associated with foodborne diseases, are related to contamination of the food products by pathogenic microorganisms, such as Salmonella and Listeria monocytogenes. The use of bacteriophages emerges as a possible solution to reduce and eliminate the bacterial load of these microorganisms present in foods, since these kind of viruses, are safe for human consumption and specific for certain microorganisms, which makes them excellent tools for food safety purposes. However, it is known that bacteriophages lose viability throughout storage and after application, due to environmental conditions such as pH, temperature, ions, salinity, osmotic pressure and exposure to organic solvents, and as such it is essential to find protection methodologies so that they maintain full activity when added directly to food products. Microencapsulation, arises as a solution, yet, in an economic point of view, some of the actual encapsulation methods are expensive, and others use temperature during the process which unviable their use for bacteriophages encapsulation. So, there’s a need to find a new cost-effective microencapsulation technology, for production of bacteriophage-loaded microcapsules, being that microfluidics, emerge as a viable solution. The main objective of this work, consist in the use of microfluidics to generate microstructures with food grade biopolymers (agarose), loaded with a natural antibacterial agent, the bacteriophages. The droplet formation process was optimized and the “On-Chip” and “Off-Chip mixing” techniques developed, followed by the characterization of the obtained droplets, where it was verified that a size of 85 μm was achieved using the On-Chip technique. A high-throughput formation of monodisperse agarose beads, in a very controlled and automated way, was accomplished, being that the entire production process malleable. A phage release of about 60% was obtained in the first 5 minutes, without the need of any external triggers. In conclusion, the developed technology opens a new path for the deployment of new products for food safety purposes., Ao longo dos anos, nos países desenvolvidos, tem-se verificado um aumento da preocupação, por parte dos consumidores, relativamente à segurança dos alimentos que ingerem. O estilo de vida tem levado a uma crescente procura por produtos de conveniência, seguido de fruta e vegetais minimamente processados, referidos como produtos “fresh-cut”. Muitos dos surtos causados pela ingestão de alimentos, estão associados à contaminação destes por parte de microrganismos patogénicos, como Salmonella e Listeria monocytogenes. O uso de bacteriófagos emerge como uma possível solução para reduzir e eliminar a carga destes microrganismos nos alimentos, uma vez que são seguros para consumo e específicos para determinados microrganismos, o que os torna excelentes ferramentas para fins de segurança alimentar. Contudo, sabe-se que os bacteriófagos perdem viabilidade ao longo do armazenamento e após aplicação devido a condições ambientais, sendo essencial encontrar metodologias de proteção para que os mesmos mantenham total atividade quando adicionados diretamente nos produtos alimentares. A microencapsulação surge como uma solução, no entanto, de um ponto de vista económico, grande parte dos métodos de encapsulação atuais são caros e alguns dos métodos usam temperatura durante o processo o que inviabiliza o seu uso para a encapsulação dos bacteriófagos. Há assim uma necessidade de encontrar uma tecnologia de microencapsulação economicamente viável para produção de microcápsulas carregadas com bacteriófagos, sendo que a microfluídica pode ser uma solução viável. O principal objetivo deste trabalho consiste no uso da microfluídica para gerar estruturas micrométricas, com biopolímeros de grau alimentar (agarose), carregadas com um agente antibacteriano natural, os bacteriófagos. O processo de formação de capsulas recorrendo á microfluidica, foi otimizado, e as técnicas de encapsulamento “On-Chip” e “Off-Chip” desenvolvidas, procedendo-se á caracterização das capsulas obtidas. Um tamanho de 85 μm foi alcançado, recorrendo á técnica “On-Chip”. Verificou-se também uma alta taxa de produção de capsulas, assim como um elevado nível de monodispersividade, sendo todo o processo de produção flexível, recorrendo á referida técnica desenvolvida. Obteve-se uma libertação de fagos de cerca de 60% nos primeiros 5 minutos, sem a adição de um agente externo. Em conclusão, esta tecnologia abre caminho para a implementação de produtos eficazes para controle de segurança alimentar.