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195 result(s) for "Cerqueira, Miguel A."
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Oleogel-Based Systems for the Delivery of Bioactive Compounds in Foods
Oleogels are semi-solid materials containing a large fraction of liquid oil entrapped in a network of structuring molecules. In the food industry, these formulations can be used to mimic fats and to deliver bioactive compounds. In the last decade, there has been increasing interest in these structures, not only from a scientific point of view, i.e., studying new molecules, methodologies for gelification, and new structures, but also from a technological point of view, with researchers and companies exploring these structures as a way to overcome certain challenges and/or create new and innovative products. One of the exciting applications of oleogels is the delivery of functional molecules, where the incorporation of oil-soluble functional compounds can be explored not only at the macroscale but also at micro- and nanoscales, resulting in different release behaviors and also different applications. This review presents and discusses the most recent works on the development, production, characterization, and applications of oleogels and other oleogel-based systems to deliver functional molecules in foods.
Bacteriophage Delivery Systems for Food Applications: Opportunities and Perspectives
Currently, one-third of all food produced worldwide is wasted or lost, and bacterial contamination is one of the main reasons. Moreover, foodborne diseases are a severe problem, causing more than 420,000 deaths and nearly 600 million illnesses yearly, demanding more attention to food safety. Thus, new solutions need to be explored to tackle these problems. A possible solution for bacterial contamination is using bacteriophages (phages), which are harmless to humans; these natural viruses can be used to prevent or reduce food contamination by foodborne pathogens. In this regard, several studies showed the effectiveness of phages against bacteria. However, when used in their free form, phages can lose infectivity, decreasing the application in foods. To overcome this problem, new delivery systems are being studied to incorporate phages and ensure prolonged activity and controlled release in food systems. This review focuses on the existent and new phage delivery systems applied in the food industry to promote food safety. Initially, an overview of phages, their main advantages, and challenges is presented, followed by the different delivery systems, focused in methodologies, and biomaterials that can be used. In the end, examples of phage applications in foods are disclosed and future perspectives are approached.
Bacteriophages for Chronic Wound Treatment: From Traditional to Novel Delivery Systems
The treatment and management of chronic wounds presents a massive financial burden for global health care systems, with significant and disturbing consequences for the patients affected. These wounds remain challenging to treat, reduce the patients’ life quality, and are responsible for a high percentage of limb amputations and many premature deaths. The presence of bacterial biofilms hampers chronic wound therapy due to the high tolerance of biofilm cells to many first- and second-line antibiotics. Due to the appearance of antibiotic-resistant and multidrug-resistant pathogens in these types of wounds, the research for alternative and complementary therapeutic approaches has increased. Bacteriophage (phage) therapy, discovered in the early 1900s, has been revived in the last few decades due to its antibacterial efficacy against antibiotic-resistant clinical isolates. Its use in the treatment of non-healing wounds has shown promising outcomes. In this review, we focus on the societal problems of chronic wounds, describe both the history and ongoing clinical trials of chronic wound-related treatments, and also outline experiments carried out for efficacy evaluation with different phage-host systems using in vitro, ex vivo, and in vivo animal models. We also describe the modern and most recent delivery systems developed for the incorporation of phages for species-targeted antibacterial control while protecting them upon exposure to harsh conditions, increasing the shelf life and facilitating storage of phage-based products. In this review, we also highlight the advances in phage therapy regulation.
Bio-Based Nanoparticles as a Carrier of β-Carotene: Production, Characterisation and In Vitro Gastrointestinal Digestion
β-carotene loaded bio-based nanoparticles (NPs) were produced by the solvent-displacement method using two polymers: zein and ethylcellulose. The production of NPs was optimised through an experimental design and characterised in terms of average size and polydispersity index. The processing conditions that allowed to obtain NPs (<100 nm) were used for β-carotene encapsulation. Then β-carotene loaded NPs were characterised in terms of zeta potential and encapsulation efficiency. Transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction analysis were performed for further morphological and chemical characterisation. In the end, a static in vitro digestion following the INFOGEST protocol was performed and the bioaccessibility of β-carotene encapsulated in both NPs was determined. Results show that the best conditions for a size-controlled production with a narrow size distribution are lower polymer concentrations and higher antisolvent concentrations. The encapsulation of β-carotene in ethylcellulose NPs resulted in nanoparticles with a mean average size of 60 ± 9 nm and encapsulation efficiency of 74 ± 2%. β-carotene loaded zein-based NPs resulted in a mean size of 83 ± 8 nm and encapsulation efficiency of 93 ± 4%. Results obtained from the in vitro digestion showed that β-carotene bioaccessibility when encapsulated in zein NPs is 37 ± 1%, which is higher than the value of 8.3 ± 0.1% obtained for the ethylcellulose NPs.
Strategy towards Replacing Pork Backfat with a Linseed Oleogel in Frankfurter Sausages and Its Evaluation on Physicochemical, Nutritional, and Sensory Characteristics
Different health institutions from western countries ha–ve recommended a diet higher in polyunsaturated fats, especially of the n-3 family. However, this is not a trivial task, especially for meat-processing sectors. The objective of this work was to assess the influence of replacing pork backfat with linseed oleogel on the main quality parameters of frankfurters. The frankfurters were formulated by the pork backfat replacement of 0% (control), 25% (SF-25), and 50% (SF-50), using a linseed oleogel gelled with beeswax. The determination of quality parameters (pH, colour, chemical composition, and texture parameters), the fatty acid profile, and the sensory evaluation was carried out for each batch. The fatty acid profile was substantially improved, and the saturated fatty acid (SFA) content was reduced from 35.15g/100g in control sausages to 33.95 and 32.34g/100 g in SF-25 and SF-50, respectively, and more balanced ratios n-6/n-3 were achieved. In addition, the sausages with linseed oleogel also decreased the cholesterol content from 25.08 mg/100 g in control sausages to 20.12 and 17.23 mg/100 g in SF-25 and SF-50, respectively. It may therefore be concluded that these innovative meat products are a healthier alternative. However, sensory parameters should be improved in order to increase consumer acceptability, and further research is needed.
Quercetin-Loaded Lecithin/Chitosan Nanoparticles for Functional Food Applications
This study aimed at the encapsulation of quercetin into lecithin/chitosan nanoparticles using the electrostatic self-assembly technique, followed by evaluation of their functionality (antioxidant activity) and stability at different environmental conditions. These nanoparticles were characterized in terms of: average size, morphology, zeta potential, encapsulation efficiency, loading, and spectroscopic characteristics. Quercetin has been successfully encapsulated in lecithin/chitosan nanoparticles with an efficiency of 96.13 ± 0.44 %. Nanoparticles presented a spherical morphology with an average size of 168.58 ± 20.94 nm and a zeta potential of 56.46 ± 1.94 mV. Stability studies showed that nanoparticles are stable to temperatures ranging between 5 and 70 °C and a pH variation from 3.3 to 5.0. Moreover, encapsulated quercetin showed improved antioxidant properties when compared to free-quercetin. Our results suggest that quercetin-loaded lecithin/chitosan nanoparticles can be used in the manufacture of functional foods.
Development of Chitosan-Based Surfaces to Prevent Single- and Dual-Species Biofilms of Staphylococcus aureus and Pseudomonas aeruginosa
Implantable medical devices (IMDs) are susceptible to microbial adhesion and biofilm formation, which lead to several clinical complications, including the occurrence of implant-associated infections. Polylactic acid (PLA) and its composites are currently used for the construction of IMDs. In addition, chitosan (CS) is a natural polymer that has been widely used in the medical field due to its antimicrobial and antibiofilm properties, which can be dependent on molecular weight (Mw). The present study aims to evaluate the performance of CS-based surfaces of different Mw to inhibit bacterial biofilm formation. For this purpose, CS-based surfaces were produced by dip-coating and the presence of CS and its derivatives onto PLA films, as well surface homogeneity were confirmed by contact angle measurements, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The antimicrobial activity of the functionalized surfaces was evaluated against single- and dual-species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. Chitosan-based surfaces were able to inhibit the development of single- and dual-species biofilms by reducing the number of total, viable, culturable, and viable but nonculturable cells up to 79%, 90%, 81%, and 96%, respectively, being their activity dependent on chitosan Mw. The effect of CS-based surfaces on the inhibition of biofilm formation was corroborated by biofilm structure analysis using confocal laser scanning microscopy (CLSM), which revealed a decrease in the biovolume and thickness of the biofilm formed on CS-based surfaces compared to PLA. Overall, these results support the potential of low Mw CS for coating polymeric devices such as IMDs where the two bacteria tested are common colonizers and reduce their biofilm formation.
Active Carboxymethyl Cellulose-Based Edible Coatings for the Extension of Fresh Goldenberries Shelf-Life
Edible coatings based on natural sources are a good alternative to protect and increase the shelf-life of the fruits. In this work, active carboxymethyl cellulose (CMC)-based edible coatings enriched with functional ingredients, extracted from spent coffee grounds (SCG), were produced and used to increase the shelf-life of fresh goldenberries. Thus, three different treatments were tested on fresh goldenberries: (i) coating CMC (CMC-based edible coating); (ii) coating CMC-A (CMC-based edible coating with 0.2% (w/v) of polysaccharide-rich extract from SCG); and (iii) coating CMC-B (CMC-based edible coating with 0.2% (w/v) of polysaccharide-rich extract, and 0.2% (w/v) of phenolic compounds encapsulated from SCG), being compared with uncoated goldenberries. Physicochemical and microbiological properties of the fruits were evaluated throughout 12 and 28 days of storing at 20 °C and 65% relative humidity and 4 °C and 95% RH, respectively. The results showed that the temperature and relative humidity significantly influenced the quality of goldenberries, increasing their shelf-life almost two-fold when stored at 4 °C and 95% RH. Both CMC-A and CMC-B coatings controlled weight loss and decreased the gas transfer rates (O2, CO2, and C2H4), mainly when goldenberries were stored at 20 °C and 65% RH. Moreover, coating CMC-A was better for delaying microbial growth, while the edible coating CMC-B gave an extra content of phenolic compounds to goldenberries, increasing thus their antioxidant potential.
The Effect of Molecular Weight on the Antimicrobial Activity of Chitosan from Loligo opalescens for Food Packaging Applications
The growing requirement for sustainable processes has boosted the development of biodegradable plastic-based materials incorporating bioactive compounds obtained from waste, adding value to these products. Chitosan (Ch) is a biopolymer that can be obtained by deacetylation of chitin (found abundantly in waste from the fishery industry) and has valuable properties such as biocompatibility, biodegradability, antimicrobial activity, and easy film-forming ability. This study aimed to produce and characterize poly(lactic acid) (PLA) surfaces coated with β-chitosan and β-chitooligosaccharides from a Loligo opalescens pen with different molecular weights for application in the food industry. The PLA films with native and depolymerized Ch were functionalized through plasma oxygen treatment followed by dip-coating, and their physicochemical properties were assessed by Fourier-transform infrared spectroscopy, X-ray diffraction, water contact angle, and scanning electron microscopy. Their antimicrobial properties were assessed against Escherichia coli and Pseudomonas putida, where Ch-based surfaces reduced the number of biofilm viable, viable but nonculturable, and culturable cells by up to 73%, 74%, and 87%, respectively, compared to PLA. Biofilm growth inhibition was confirmed by confocal laser scanning microscopy. Results suggest that Ch films of higher molecular weight had higher antibiofilm activity under the food storage conditions mimicked in this work, contributing simultaneously to the reuse of marine waste.
Characterization of Sodium Alginate-Based Films Blended with Olive Leaf and Laurel Leaf Extracts Obtained by Ultrasound-Assisted Technology
Due to environmental concerns, there is an increasing need to reduce the use of synthetic and non-renewable packaging materials to reduce waste and increase sustainability. This study aimed to characterise sodium alginate edible-based films (SA) incorporated with laurel leaf extract (LLE) and olive leaf extract (OLE) obtained by ultrasound-assisted extraction. Determination of total phenolic content, antioxidant, and antimicrobial activity was performed for the extracts and films. Also, thickness, tensile strength, elongation at break, modulus of elasticity, opacity and colour, moisture content, water vapour permeability (WVP), Fourier-transform infrared spectroscopy (FTIR) spectra, and surface morphology by scanning electron microscope (SEM) analyses were performed for the films. LLE yielded better results in terms of phenolic content (195 mg GAE/g), antioxidant (2.1 TE/g extract) and antimicrobial activity (MIC at 1% for Listeria monocytogenes and Staphylococcus aureus, and 1.8% for Enterococcus faecalis). For the films, the simultaneous incorporation of LLE 1% (w/v) and OLE 1% (w/v) resulted in a significant reduction of approximately 2 log CFU/g against S. aureus. The addition of LLE and OLE extracts also proved to improve barrier properties (lower WVP for SA films with LLE 1% + OLE 1%, 3.49 × 10−11 g m−1 s−1 Pa−1) and promoted changes in resistance and flexibility. The results demonstrated that active alginate-based films can be valuable for enhancing food preservation.