Publications by authors named "Berta N Estevinho"

Valorization of agricultural and food by-products (agri-food waste) and maximum utilization of this raw material constitute a highly relevant topic worldwide. Agri-food waste contains different types of phytochemical compounds such as polyphenols, that display a set of biological properties, including anti-inflammatory, chemo-preventive, and immune-stimulating effects. In this work, the microencapsulation of strawberry () plant extract was made by spray-drying using individual biopolymers, as well as binary and ternary blends of pectin, alginate, and carrageenan.

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Vitamin E encapsulation into biopolymer-based microparticles, obtained by spray-drying technology, was proposed to improve the encapsulation efficiency and the controlled release of fat-soluble vitamin. Binary and ternary blends of pectin, modified chitosan and modified starch, modified starch + modified chitosan, modified starch + pectin, modified chitosan + pectin and modified starch + modified chitosan + pectin ((0.33, 0.

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An innovative approach for the production of bio-micro/nanostructures with high-value compounds from agricultural by-products was studied. This research aimed to valorize bioactive compounds existing in the by-products of the plants of (wild strawberry). The particle characteristics, morphology, size, release properties, and antioxidant activity of micro/nanostructures containing the extract of by-products of the plants of or quercetin (one of the main polyphenols in the plant) were analyzed.

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The development of carrier-based delivery systems for oral administration of retinoic acid (RA), that provides its release and absorption at intestinal level, is of major relevance in the treatment of acute promyelocytic leukemia. The aim of this work was to evaluate RA bioaccessibility and intestinal transport on ethyl cellulose (EC)- and EC + polyethylene glycol (ECP)-based microparticles and to understand the impact of meal co-ingestion by applying in vitro assays. RA-loaded microparticles were produced by spray-drying with an encapsulation efficiency higher than 90 % for both formulations.

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Acute promyelocytic leukemia (APL) is phenotypically characterized by the accumulation of dysplastic promyelocytes, resulting from a cytogenetic condition due to the balanced chromosomal translocation t(15;17)(q22;q21). Current first-line treatment of APL includes all-trans retinoic acid (all-trans RA), with or without arsenic trioxide, combined with chemotherapy, and a chemotherapy-free approach wherein arsenic trioxide is used alone or in combination with all-trans RA. The usage of all-trans RA revolutionized the treatment of APL, with survival rates of 80 to 90% being achieved.

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Extracts from plants have been one of the main sources of antioxidants, namely polyphenols. The associated drawbacks, such as instability against environmental factors, low bioavailability, and loss of activity, must be considered during microencapsulation for a better application. Electrohydrodynamic processes have been investigated as promising tools to fabricate crucial vectors to minimize these limitations.

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Article Synopsis
  • EGCG is a beneficial antioxidant and vitamin B12 is essential for health, but both can lose effectiveness during processing due to stability issues.
  • Microencapsulation using a biological polymer called zein was explored to protect these compounds, with various concentrations tested via an electrospinning technique.
  • The study found high encapsulation efficiency, particularly with 1% active substance and 30% zein, and the release profiles were best explained by the Weibull model during controlled release tests.
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Co-encapsulation of retinoic acid (RA), curcumin and/or resveratrol into microparticles composed by alginic acid sodium and the ethyl cellulose + polyethylene glycol (EC + PEG) blend was proposed for the protection and co-delivery of these bioactive compounds. The final aim is to take benefit of combined therapeutic potential related to these molecules and use loaded microparticles obtained by spray-drying to improve the treatment of acute promyelocytic leukemia (APL). Alginic acid sodium-based emulsions were characterized regarding rheological properties (i.

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The food industry has been expanding, and new vectors to entrap vitamins have been constantly investigated, aiming at versatile systems with good physico-chemical characteristics, low-cost production, high stability and the efficient release of active ingredients. The vitamin B9 (folic acid or folate) is essential for the healthy functioning of a variety of physiological processes in humans and is beneficial in preventing a range of disorders. In this study, two approaches were developed to encapsulate vitamin B9.

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Ethyl cellulose (EC)-based microparticles, with and without the incorporation of polyethylene glycol (PEG) as a second encapsulating agent, were prepared using the spray-drying process for the encapsulation of retinoic acid (RA). The production of a suitable controlled delivery system for this retinoid will promote its antitumor efficiency against acute promyelocytic leukemia (APL) due to the possibility of increasing the bioavailability of RA. Product yield ranged from 12 to 28% in all the microparticle formulations, including unloaded microparticles and RA-loaded microparticles.

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Epigallocatechin gallate (EGCG) is a catechin and one of the most abundant polyphenols in green tea, and it is under research for its potential benefit to human health and for its potential to be used in disease treatments, such as for cancer. However, the effectiveness of polyphenols depends on preserving their bioactivity, stability, and bioavailability. The EGCG was microencapsulated by a spray-drying process, using different biopolymers as encapsulating agents (gum arabic, modified chitosan and sodium alginate), in order to overcome some of the limitations of this compound.

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Water-soluble vitamins are essential micronutrients in diets and crucial to biochemical functions in human body physiology. These vitamins are essential for healthy diets and have a preventive role against diseases. However, their limitations associated with high sensitivity against external conditions (temperature, light, pH, moisture, oxygen) can lead to degradation during processing and storage.

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Electrohydrodynamic techniques have been focus for the development of structures for encapsulation purposes. Their physico-chemical characteristics confer them significant benefits for food and nutraceutical applications. The study reports the optimization of zein microstructures (electrosprayed beads/electrospun fibers/films).

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MSI-78A (Pexiganan A) is one of the few antimicrobial peptides (AMPs) able to kill Helicobacter pylori, a pathogenic bacterium that colonizes the gastric mucosa of half of the world's population. Antibiotics fail in 20-40% of H. pylori-infected patients, reinforcing the need for alternative treatments.

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Retinoid acid (RA) and other retinoids are extensively used as therapeutic agents in the treatment of several types of cancer and skin disorders. However, the efficiency of these medical agents is compromised due to the unsatisfactory concentration of retinoids in the target cells/tissues. Furthermore, severe side-effects are related to retinoids administration.

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Enzymatically-active bacterial cellulose (BC) was prepared by non-covalent immobilization of a hybrid enzyme composed by a β-galactosidase from Thermotoga maritima (TmLac) and a carbohydrate binding module (CBM2) from Pyrococcus furiosus. TmLac-CBM2 protein was bound to BC, with higher affinity at pH 6.5 than at pH 8.

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Preparing stable protein-based microcapsules containing functional fatty acids and oils for food applications has been a big challenge. However, recent advances with transglutaminase (TGase) enzyme as an effective protein cross-linker could provide workable solutions for the encapsulation of omega-3 and omega-6 fatty acids without compromising their targeted release and their biological and physicochemical characteristics. The recent and available literature related to the microencapsulation techniques, physical and oxidative properties, and core retention and release mechanisms of TGase-crosslinked microcapsules entrapping edible oils were reviewed.

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Molinate is a thiocarbamate herbicide used in rice crop protection. As other pesticides, molinate is a recognized environmental pollutant and bio-accumulated by some wildlife forms. Gulosibacter molinativorax ON4 is able to hydrolyse molinate into metabolites which are further degraded by other un-related bacteria.

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Previous studies demonstrated the capability of mixed culture DC1 to mineralize the thiocarbamate herbicide molinate through the activity of molinate hydrolase (MolA). Because liquid suspensions are not compatible with long-term storage and are not easy to handle when bioremediation strategies are envisaged, in this study spray drying was evaluated as a cost-effective method to store and transport these molinate biocatalysts. Microparticles of mixed culture DC1 (DC1) and of cell free crude extracts containing MolA (MA) were obtained without any carrier polymer, and with calcium alginate (CA) or modified chitosan (MCt) as immobilizing agents.

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The objective of this work was to investigate the influence of pH in the microencapsulation process, using a modified chitosan to microencapsulate the enzyme β-galactosidase, by a spray-drying technique. Structural analysis of the surface of the particles was performed by scanning electron microscopy (SEM), showing that the obtained microparticles have an average diameter smaller than 3.5 μm and in general a regular shape.

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The methodology adopted by Michaelis and Menten in 1913 is still routinely used to characterize the catalytic power and selectivity of enzymes. These kinetic measurements must be performed soon after the purified enzyme is mixed with a large excess of substrate. Other time scales and solution compositions are no less physiologically relevant, but fall outside the range of applicability of the classical formalism.

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The aim of this work was to investigate the possibility of producing microparticles containing β-galactosidase, using different biopolymers (arabic gum, chitosan, modified chitosan, calcium alginate and sodium alginate) as encapsulating agents by a spray-drying process. This study focused on the enzyme β-galactosidase, due to its importance in health and in food processing. Encapsulation of β-galactosidase can increase the applicability of this enzyme in different processes and applications.

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The determination of glucose and other carbohydrates is the most widespread chemical analysis that is performed within the industries of food, beverage, forage, biomass, pulp and paper, pharmaceuticals among others. Besides that, sugar refineries need to control their products, by-products and effluents, and furthermore, glucose in the sucrose refining process, is considered an impurity, which shall be controlled. Being HPLC the most currently instrumental technique used for glucose analysis, the evaporative light scattering detector (ELSD) offers advantages (sensitivity, possibility for operating in gradient mode) over the also used refractive index detector.

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Chlorophenols are one of the most important groups of priority pollutants, due to their high toxicity, mutagenicity and carcinogenicity. Although activated carbon has been the preferred choice for the removal of such pollutants from wastewaters, the search for cheaper alternative sorbents became common in the last years. Fly ash, a by-product from coal burning power plants, has a surface composition that may enable the sorption of specific organic compounds.

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