The use of electric fields for edible coatings and films development and production: A review

Edible films and coatings can provide additional protection for food, while being a fully biodegradable, environmentally friendly packaging system. A diversity of raw materials used to produce edible coatings and films are extracted from marine and agricultural sources, including animals and plants. Electric fields processing holds advantage in producing safe, wholesome and nutritious food. Recently, the presence of a moderate electric field during the preparation of edible coatings and films was shown to influence their main properties, demonstrating its usefulness to tailor edible films and coatings for specific applications. This manuscript reviews the main aspects of the use of electric fields in the production of edible films and coatings, including the effect in their transport and mechanical properties, solubility and microstructure.Fundação para a Ciência e a Tecnologia (FCT), Portugal.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brasil

Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Antimicrobial activity of Ti-ZrN/Ag coatings for use in biomaterial applications

Severely broken bones often require external bone fixation pins to provide support but they can become infected. In order to reduce such infections, novel solutions are required. Titanium zirconium nitride (Ti-ZrN) and Ti-ZrN silver (Ti-ZrN/Ag) coatings were deposited onto stainless steel. Surface microtopography demonstrated that on the silver containing surfaces, Sa and Sv values demonstrated similar trends whilst the Ra, average height and RMS value and Sp values increased with increasing silver concentration. On the Ti-ZrN/Ag coatings, surface hydrophobicity followed the same trend as the Sa and Sv values. An increase in dead Staphylococcus aureus and Staphylococcus epidermidis cells was observed on the coatings with a higher silver concentration. Using CTC staining, a significant increase in S. aureus respiration on the silver containing surfaces was observed in comparison to the stainless steel control whilst against S. epidermidis, no significant difference in viable cells was observed across the surfaces. Cytotoxicity testing revealed that the TiZrN coatings, both with and without varying silver concentrations, did not possess a detrimental effect to a human monocyte cell line U937. This work demonstrated that such coatings have the potential to reduce the viability of bacteria that result in pin tract infections

Neuroprotective mechanisms of dieckol against glutamate toxicity through reactive oxygen species scavenging and nuclear factor-like 2/heme oxygenase-1 pathway

Glutamate toxicity-mediated mitochondrial dysfunction and neuronal cell death are involved in the pathogenesis of several neurodegenerative diseases as well as acute brain ischemia/stroke. In this study, we investigated the neuroprotective mechanism of dieckol (DEK), one of the phlorotannins isolated from the marine brown alga Ecklonia cava, against glutamate toxicity. Primary cortical neurons (100 mu M, 24 h) and HT22 neurons (5 mM, 12 h) were stimulated with glutamate to induce glutamate toxic condition. The results demonstrated that DEK treatment significantly increased cell viability in a dose-dependent manner (1-50 mu M) and recovered morphological deterioration in glutamate-stimulated neurons. In addition, DEK strongly attenuated intracellular reactive oxygen species (ROS) levels, mitochondrial overload of Ca2+ and ROS, mitochondrial membrane potential (Delta psi(m)) disruption, adenine triphosphate depletion. DEK showed free radical scavenging activity in the cell-free system. Furthermore, DEK enhanced protein expression of heme oxygenase-1 (HO-1), an important anti-oxidant enzyme, via the nuclear translocation of nuclear factor-like 2 (Nrf2). Taken together, we conclude that DEK exerts neuroprotective activities against glutamate toxicity through its direct free radical scavenging property and the Nrf-2/HO-1 pathway activation. © Korean J Physiol Pharmacol11Nsciekc