Browsing Agrotecnio Center by Author "Acevedo Fani, Alejandra"
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- ItemOpen AccessDevelopment, physical stability and bioaccessibility of β-carotene-enriched tertiary emulsions(Elsevier, 2019-10-31) Gasa Falcón, Ariadna; Acevedo Fani, Alejandra; Oms Oliu, Gemma; Odriozola Serrano, Isabel; Martín Belloso, OlgaThe aim of this study was to develop a β-carotene-enriched tertiary emulsion (lactoferrin/alginate/ε-poly-L-lysine). Then, its physical stability as well as β-carotene content under external stresses (temperature, pH and ionic strength changes) was evaluated. Furthermore, lipid digestibility and β-carotene bioaccessibility of primary, secondary and tertiary emulsions were determined. Tertiary emulsion underwent a substantial particle size increase up to 13 μm after extreme temperatures, acidic conditions and with salt addition. However, small particle size (0.41 μm) and negative ζ-potential (-43.4 mV) was observed at basic pH. In addition, β-carotene content in tertiary emulsions decreased only 40% when emulsions were subjected at temperatures ≤70ºC, in acidic conditions and below 0.3M NaCl. After in vitro digestion, tertiary emulsion presented higher lipid digestibility (83.59±11.81%) and β-carotene bioaccessibility (70.10±5.26%) compared with primary and secondary emulsions. This study provides knowledge to understand the behaviour of β-carotene-loaded tertiary emulsions under different conditions, valuable for further application in foodstuffs.
- ItemOpen AccessEdible films from essential-oil-loaded nanoemulsions: physicochemical characterization and antimicrobial properties(Elsevier, 2015-05-01) Acevedo Fani, Alejandra; Salvia Trujillo, Laura; Rojas Grau, María Alejandra; Martín Belloso, OlgaEdible films including active ingredients can be used as an alternative to preserve food products. Essential oils (EOs) exhibit antimicrobial activity against pathogenic microorganisms but their low water solubility limits the application in foods. To improve water dispersion and protect EOs from degradation, nano-sized emulsions emerge as a viable alternative. Nanoemulsions containing EOs and polysaccharides could be used to form edible films with functional properties. This study was focused on the evaluation of physical, mechanical and antimicrobial properties of alginate-based edible films formed from nanoemulsions of EOs. Nanoemulsions containing thyme (TH-EO), lemongrass (LG-EO) or sage (SG-EO) oil as dispersed phase and sodium alginate solution as continuous phase were prepared. The average droplet size of nanoemulsions was reduced after the microfluidization treatment exhibiting multimodal size distributions. The zeta-potentials of nanoemulsions were between 41 mV and 70 mV depending on the type of EO used. The lowest whiteness index was found in SG-EO nanoemulsions, whereas those containing TH-EO showed the highest value. Films formed from SG-EO nanoemulsions exhibited higher transparency, water vapor resistance and flexibility than films formed from TH-EO or LG-EO. Edible films containing TH-EO were those with the strongest antimicrobial effect against inoculated Escherichia coli, achieving up to 4.71 Log reductions after 12 h. Results obtained in the present work evidence the suitability of using nanoemulsions with active ingredients for the formation of edible films, with different physical and functional properties. (C) 2015 Elsevier Ltd. All rights reserved
- ItemOpen AccessEffect of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions(Elsevier, 2017) Artiga Artigas, María; Acevedo Fani, Alejandra; Martín Belloso, OlgaThe aim of this work was to evaluate the effect of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions formed by microfluidization. Emulsions prepared consisted of corn oil and Tween 20 as dispersed phase and sodium alginate solution as continuous phase. In order to obtain nanoemulsion A (NA), both phases were microfluidized together. On the other hand, coarse emulsion without sodium alginate was microfluidized and mixed with a microfluidized (MA) or non-microfluidized (N-MA) sodium alginate solution leading to nanoemulsions B(MA) and B(N-MA), respectively. NA exhibited the smallest particle size (261 nm) and monomodal distributions with a polydispersity index of 0.25. The ζ-potential, viscosity and WI of NA were −37 mV, 22.7 mPa s and 57.28, respectively. Spectroscopic, chromatographic and electron microscopic techniques were used to evaluate changes in microfluidized alginate molecules when they were within emulsions. After microfluidization, alginates suffered depolymerization and further rearrangement, changing the disposition of polymer chains around oil droplets and nanoemulsions characteristics. Thus, these results evidence the significant impact of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions and how it can affect to the stability of the resulting systems which are going to be used as functional ingredients in food matrices.
- ItemOpen AccessEncapsulation and stability of a phenolic-rich extract from mango peel within water-in-oil-in-water emulsions(Elsevier, 2019) Velderrain Rodríguez, Gustavo R.; Acevedo Fani, Alejandra; González-Aguilar, Gustavo A.; Martín Belloso, OlgaMango peel is an excellent source of compounds with nutritional and functional properties, especially phenolic compounds (PC). However, it is usually discarded due to its unpleasant taste and its difficulty to be added to food products. As a solution, we evaluated the feasibility of encapsulating a phenolic-rich extract from mango peel (MPPE) within water-in-oil-in-water (W1/O/W2) emulsions, using different surfactants (Tween 20, Tween 80 and lecithin). Time and amplitude conditions of ultrasound treatment were evaluated to form the MPPE loaded water-in-oil (W/O) emulsions, using polyglycerol polyricinoleate (PGPR) as a surfactant. Regarding of W1/O/W2 emulsions, the highest encapsulation efficiency (EE) was observed in those with Tween 20 and lecithin (98.65 ± 1.14% and 96.11 ± 1.37%, respectively). However, emulsions with Tween 80 had the best physical and encapsulation stability (ES) during storage. These results demonstrate that PC can be successfully encapsulated within efficient and stable emulsion-based systems by selecting the appropriate surfactants.
- ItemOpen AccessFormation, stability and antioxidant activity of food-grade multilayer emulsions containing resveratrol(Elsevier, 2017) Acevedo Fani, Alejandra; Silva, Hélder Daniel; Soliva-Fortuny, Robert; Martín Belloso, Olga; Vicente, António AugustoInterfacial deposition of biopolymer layers on oil droplets may be a suitable strategy for increasing the emulsion stability and protection of functional ingredients. Resveratrol is a naturally occurring phenolic compound with numerous health-promoting properties, but its usage is still restricted due to its poor water solubility and high chemical instability. The aim of this study was to formulate single-layer (lactoferrin) and multilayer (lactoferrin/alginate and lactoferrin/alginate/ε-poly-l-lysine) emulsions containing resveratrol and to study the emulsions stability and antioxidant activity during storage. All primary (single-layer) emulsions had average droplet diameters below 300 nm and ζ-potentials strongly positive, allowing the electrostatic deposition of another layer of anionic biopolymer, such as alginate. Secondary (multilayer) emulsions were highly unstable at low alginate concentrations, which was attributed to the bridging flocculation. At higher alginate concentrations, secondary emulsions were rather stable. Tertiary emulsions containing either low or high ε-poly-l-lysine concentrations presented flocculation, but formulations with 0.0036% (w/w) were fairly stable. The antioxidant activity of all resveratrol-loaded emulsions did not significantly change during storage, whereas it decreased in non-encapsulated resveratrol oil from the third week onwards. This study provides useful information for the design of delivery systems for resveratrol with relevance in food applications.
- ItemOpen AccessImproving the shelf life of low-fat cut cheese using nanoemulsion-based edible coatings containing oregano essential oil and mandarin fiber(Elsevier, 2017) Artiga Artigas, María; Acevedo Fani, Alejandra; Martín Belloso, OlgaNanoemulsion-based edible coatings containing oregano essential oil (OEO) as antimicrobial were applied onto low-fat cut cheese to extend its shelf life. Nanoemulsions formulation was 2.0% (w/w) sodium alginate, 0.5% (w/w) mandarin fiber, 2.5% (w/w) Tween 80 and 1.5%, 2.0% or 2.5% (w/w) of OEO. Particle size, ζ-potential, apparent viscosity and whiteness index of nanoemulsions were assessed. Water vapor resistance of coatings was evaluated as well as their antimicrobial efficiency against inoculated Staphylococcus aureus and native microbiota growth during refrigerated storage. Headspace gases were measured as an indicator of bacterial activity and sensory alterations such as color and texture of cheese pieces were studied. Coatings with at least 2.0% (w/w) OEO decreased Staphylococcus aureus population from 6.0 to 4.6 log CFU/g after 15 days. Coated-cheese pieces containing 2.5% (w/w) OEO inhibited psychrophilic bacteria or molds and yeasts growth during 6 or 24 days of storage, respectively. Consequently, the atmosphere into the sealed tracks was stabilized and the outward appearance of cheese pieces was preserved. Thus, the present work evidences the feasibility of using mandarin fiber with high nutritional properties and sodium alginate acting as texturizing agents, to form OEO-loaded coatings onto low-fat cut cheese in order to extend its shelf life.
- ItemOpen AccessLayer-by-layer assembly of food-grade alginate/chitosan nanolaminates: formation and physicochemical characterization(Springer Science+Business Media New York, 2017) Acevedo Fani, Alejandra; Salvia Trujillo, Laura; Soliva-Fortuny, Robert; Martín Belloso, OlgaThe alternate deposition of oppositely charged materials (layer-by-layer technique) is an effective approach to functionalize materials. Biopolymer-based nanolaminates obtained by the layer-by-layer technique can also be used to change the surface properties of food products or food contact materials. However, the final properties of nanolaminates may be affected by the conditions of the adsorbing solutions. The objective of this study was to form and characterize the physicochemical properties of nanolaminates assembled from alginate and chitosan solutions. The effect of pH, ionic strength and polysaccharide concentration on the properties of the adsorbing solutions was also evaluated. The ζ-potential, viscosity and whiteness index of the solutions were assessed before the assembly. Alginate/chitosan nanolaminates were characterized in terms of UV-visible spectroscopy, surface ζ-potential, contact angle, DSC analysis and SEM. The absorbance increased as a function of the number of polysaccharide layers on the substrate, suggesting an increase in the mass adsorbed. The surface ζ-potential of nanolaminates changed depending on the last polysaccharide deposited. Alginate layers were negatively charged, whereas chitosan layers were positively charged. Contact angles obtained in alginate layers were ≈ 10°, being mostly hydrophilic. Chitosan layers showed higher contact angle values (80°), indicating a more hydrophobic behavior. Microscopic examinations revealed the presence densely packed structures that corresponded to alginate/chitosan nanolaminates, having an estimated thickness of 700 nm. The results obtained in this work lay the basis for the rational design of polysaccharide-based nanolaminates in the food sector.
- ItemOpen AccessModulating biopolymer electrical charge to optimize the assembly of edible multilayer nanofilms by the layer-by-layer technique(American Chemical Society, 2015) Acevedo Fani, Alejandra; Salvia Trujillo, Laura; Soliva-Fortuny, Robert; Martín Belloso, OlgaThe aim of this work was to study the influence of biopolymer (alginate, ALG; chitosan, CHI) charge on the formation of multilayer nanofilms by the layer-by-layer (LbL) technique. The electrical charge of ALG and CHI (high, medium, or low) was modulated by adjusting the pH of biopolymer solutions. The amount of biopolymer deposited in multilayers depended on the charge of ALG and CHI solutions. The lower the charge the higher the deposition rate due to the higher number of biopolymer molecules needed to neutralize the previous layer. Medium and low charge biopolymers led to a drastic change in the wettability of multilayers, with ALG layers being strongly hydrophilic and CHI layers strongly hydrophobic. The surface ζ-potential alternatively changed from negative to positive using ALG or CHI. This effect was more pronounced using highly charged biopolymers. Results obtained in this study evidenced that the multilayers properties can be tuned by controlling the biopolymer electrical charge.
- ItemOpen AccessNanostructured emulsions and nanolaminates for delivery of active ingredients: improving food safety and functionality(Elsevier, 2016) Acevedo Fani, Alejandra; Soliva-Fortuny, Robert; Martín Belloso, OlgaBackground: Nowadays, consumers are increasingly demanding high-quality, safe and healthy food products. Nanostructured emulsions and nanolaminates may have the potential to protect and transport lipophilic and hydrophilic active compounds commonly incorporated to food products, such as natural antimicrobials and nutraceuticals, while protecting or even enhancing their functional properties. Scope and approach: This review deals with the most important aspects concerning to the use of nanostructured emulsions and nanolaminates as delivery systems of active ingredients, including the advantages and challenges of incorporating plant-derived antimicrobials and nutraceuticals in foods, relevant factors affecting the formation of these nanostructures, fabrication methods, their advantages as delivery systems, and the current trends in food applications. In addition, concerns regarding the potential toxicity of nanomaterials are also discussed. Key findings and conclusions: The successful production of nanostructured emulsions and nanolaminates depends on several physicochemical factors that should be controlled in order to reach stable systems. Research evidences that nanostructured emulsions and nanolaminates are able to improve the delivery and biological activity of encapsulated active compounds. Antimicrobial and bioactive nanostructured emulsions and nanolaminates exhibit some promising advantages in food preservation and may represent a new strategy to produce functional foods. However, the knowledge in this area is still limited. The potential toxicological effects of nanostructured delivery systems are a current concern. Therefore, future investigations should be directed towards more comprehensive studies to shed light on the formation, physicochemical stability, functional performance, interactions with food matrices and toxicity of nanostructured delivery systems before their commercialization.
- ItemOpen AccessPhoto-protection and controlled release of folic acid using edible alginate/chitosan nanolaminates(Elsevier, 2018) Acevedo Fani, Alejandra; Soliva-Fortuny, Robert; Martín Belloso, OlgaThe formation, characterization, photo-protective properties and release profiles of folic acid-loaded nanolaminated films were investigated by UV-visible spectroscopy, FTIR, Raman and SEM microscopy. Food-grade alginate/chitosan nanolaminates were obtained by the layer-by-layer technique and folic acid (FA) was incorporated by post-diffusion. The FA concentration of loading solutions and immersion time significantly affected the FA content in nanolaminates. The maximum FA loading was reached using FA solutions at 10 mg/mL for 30 min (54.4 μg/cm2), or 12.5 mg/mL for 120 min (≈70 μg/cm2). Nanolaminates containing FA were more stable under ultraviolet light exposure than non-encapsulated FA. The rate and concentration of FA released from nanolaminates were greater at buffer pH 7 than at pH 3, which might play a key role in the delivery and bioavailability of nutraceuticals. These results provide important information for the design of nanolaminates containing hydrophilic active compounds for food applications.