236 research outputs found

    Encapsulation of omega-3 fatty acids in bio-based nanoemulsions: physical and chemical characterization

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    Book of Abstracts of CEB Annual Meeting 2017[Excerpt] The use of nanotechnology can offer several advantages, not only improving water solubility but also in the increase of bioavailability of lipophilic bioactive compounds. Omega-3 polyunsaturated fatty acids (ω-3 fatty acids) are known for their functional properties such as: improving cardiovascular health, decrease inflammation, increase cognitive function, and positively influence neurological and visual development. However, ω-3 fatty acids are highly susceptible to oxidation, have an intense odour and present low water solubility, which makes their direct application in foods extremely difficult. Nanoencapsulation (through nanoemulsions) may be used to reduce these problems. In this work, lactoferrin (Lf), a protein derived from milk with a wide range of reported biological activities (e.g. antioxidant, antimicrobial and cancer prevention), was used as natural emulsifier for the development of oil-in-water nanoemulsions. Nanoemulsions were produced with a high-pressure homogenizer applied for 5 cycles at 20000 psi. Different Lf concentrations (0.2; 0.6; 1; 2; 3; 4 and 5% (w/w)) were tested. The nanoemulsions’ physical properties were evaluated in terms of size and ζpotential using dynamic light scattering (DLS) and by surface tension using the Ring method. The morphology of nanoemulsions was analysed by transmission electron microscopy (TEM). The physical and chemical stability of these nanoemulsions was assessed during 50 days, at storage temperatures of 4 ÂșC and 25 ÂșC, being the chemical stability of nanoemulsions evaluated by antioxidant activity measurements using the DPPH radical scavenging assay. [...]info:eu-repo/semantics/publishedVersio

    Encapsulation and controlled release of bioactive compounds in lactoferrin-glycomacropeptide nanohydrogels : curcumin and caffeine as model compounds

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    Curcumin and caffeine (used as lipophilic and hydrophilic model compounds, respectively) were successfully encapsulated in lactoferrin-glycomacropeptide (Lf-GMP) nanohydrogels by thermal gelation showing high encapsulation efficiencies (>90 %). FTIR spectroscopy confirmed the encapsulation of bioactive compounds in Lf-GMP nanohydrogels and revealed that according to the encapsulated compound different interactions occur with the nanohydrogel matrix. The successful encapsulation of bioactive compounds in Lf-GMP nanohydrogels was also confirmed by fluorescence measurements and confocal laser scanning microscopy. TEM images showed that loaded nanohydrogels maintain their spherical shape with sizes of 112 and 126 nm for curcumin and caffeine encapsulated in Lf-GMP nanohydrogels, respectively; in both cases a polydispersity of 0.2 was obtained. The release mechanisms of bioactive compounds through Lf-GMP nanohydrogels were evaluated at pH 2 and pH 7, by fitting the Linear Superimposition Model to the experimental data. The bioactive compounds release was found to be pH-dependent: at pH 2, relaxation is the governing phenomenon for curcumin and caffeine compounds and at pH 7 Ficks diffusion is the main mechanism of caffeine release while curcumin was not released through Lf-GMP nanohydrogels

    Bio-based coatings for food processing applications

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    Innovations constantly appear in food packaging, always aiming at creating a more efficient quality preservation system while improving foods attractiveness and marketability. The utilization of renewable sources for packaging materials, such as hydrocolloids from biological origin, is one of the main trends of the food packaging industry. Edible coatings have been considered as one of the potential technologies that can be used to increase the storability of foods and to improve the existent packaging technology, helping to ensure microbial safety and preservation of food from the influence of external factors. In view of these advantages concerning the application of edible coating solutions, recent developments have been achieved regarding the utilization of new materials. Work has been developed on the application of galactomannans, chitosan, Policaju, and collagen-based coatings on fruits (1, 2), cheese (3, 4) and fish (5), with the incorporation in some cases of antimicrobials and antifungals (5,7). Recently, the layerby- layer technique was used to apply these bio-based coatings as a nanolayer in fruits such as pears and mangoes (8, 9) using materials such as chitosan, lysozyme, pectin and k-carrageenan. Globally, results showed that the application of bio-based coatings on food products lead to the improvement of the quality and to the increase of shelf-life of food products. It is viewed that in a near future tailored edible packaging solutions based on natural biopolymers can be applied to selected foods, partially replacing nonbiodegradable/ non-edible plastics.info:eu-repo/semantics/publishedVersio

    Influence of chitosan coating on protein-based nanohydrogels properties and in vitro gastric digestibility

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    Chitosan coating was applied in Lactoferrin (Lf)-Glycomacropeptide (GMP) nanohydrogels by layer-by-layer coating process. A volume ratio of 0.1 of Lf-GMP nanohydrogels (0.2 mg.mL-1, at pH 5.0) to chitosan (1 mg.mL-1, at pH 3) demonstrated to be the optimal condition to obtain stable nanohydrogels with size of 230 ± 12 nm, a PdI of 0.22 ± 0.02 and a -potential of 30.0 ± 0.15 mV. Transmission electron microscopy (TEM) images showed that the application of chitosan coating in Lf-GMP did not affect the spherical shape of nanohydrogels and confirmed the low aggregation of nanohydrogels in solution. The analysis of chemical interactions between chitosan and Lf-GMP nanohydrogels were performed by Fourier transform infrared spectroscopy (FTIR) and by circular dichroism (CD) that revealed that a specific chemical interaction occurring between functional groups of protein-based nanohydrogels and active groups of the chitosan was established. The effect of chitosan coating on release mechanisms of Lf-GMP nanohydrogels at acid conditions (pH 2, 37 ÂșC) was evaluated by the encapsulation of a model compound (caffeine) in these systems. Linear Superposition Model was used to fit the experimental data and revealed that Fick and relaxation mechanisms are involved in caffeine release. It was also observed that the Fick contribution increase with the application of chitosan coating. In vitro gastric digestion was performed with Lf-GMP nanohydrogels and Lf-GMP nanohydrogels with chitosan coating and it was observed that the presence of chitosan improve the stability of Lf and GMP (proteins were hydrolysed at a slower rate and were present in solution by longer time). Native electrophoreses revealed that the nanohydrogels without coating remained intact in solution until 15 min and with chitosan coating remained intact until 60 min, during gastric digestion.Ana I. Bourbon, Ana C. Pinheiro and Miguel A. Cerqueira acknowledge the Fundação para a CiĂȘncia e Tecnologia (FCT, Portugal) for their fellowships SFRH/BD/73178/2010, SFRH/BPD/101181/2014 and SFRH/BPD/72753/2010, respectively). The authors would like to acknowledge Jorge PadrĂŁo from CEB, University of Minho for helping in antimicrobial measurements and to Rui Fernandes from IBMC, University of Porto for assistance in taking the TEM pictures. Also, the authors would like to thank the FCT Strategic Project of UID/BIO/04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the project “BioInd – Biotechnology and Bioengineering for improved Industrial and Agro-Food processes”, REF. NORTE-07-0124-FEDER-000028 Co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER

    Transport mechanism of macromolecules on hydrophilic bio-polymeric matrices : diffusion of protein-based compounds from chitosan films

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    The transport mechanism of protein-based bioactive compounds (a peptide fraction from whey protein concentrate, glycomacropeptide and lactoferrin), from chitosan films to liquid medium, was studied. Mathematical models were used to discuss the transport mechanism. Data from release experiments was successfully described by a model which accounts for both Fick and Case II transport – the linear superimposition model. Results show that the mechanism of transport and the effect of temperature and peptide type could be related with physical properties of chitosan films where the tested bioactive compounds were incorporated. The approach presented here allows interpretation of the phenomena involved in mass transport in the systems studied and, once extended to other systems, may contribute to an understanding of transport in hydrophilic bio-polymeric matrices.This work was supported by Fundacao para a Ciencia e a Tecnologia through project PTDC/AGR/ALI/67194/2006. Authors Ana C. Pinheiro, Ana I. Bourbon and Mafalda A.C. Quintas gratefully acknowledge their Grants SFRH/BD/48120/2008, SFRH/BD/73178/2010 and SFRH/BPD/41715/2007, respectively

    Structural characterization and release profile of omega-3 fatty-acids encapsulated in nanoemulsions

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    Omega-3 (-3) fatty-acids are functional compounds with various benefits such as reduction of cardiovascular diseases. However, these fatty acids degrade quickly, present low water solubility and an unpleasant aroma, which make essential their encapsulation. The encapsulation (e.g. nanoemulsion production) process can change structural properties, which can affect the behavior of the system when applied to food matrices and within the gastrointestinal tract. The objective of this work was to characterize oil-in-water bio-based nanoemulsions with -3 using lactoferrin as a natural emulsifier, when submitted to different drying processes. Nanoemulsions were produced using high-pressure homogenization (5 cycles, 20,000 psi) using 2 % (w/w) lactoferrin and 5 % (w/w) -3. Nanoemulsions were dried by nanospray-drying (Nano Spray dryer B-90HP, Buchi) and freeze-drying methods. Physical and morphological properties were evaluated using dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. Circular dichroism (CD) and FTIR-ATR were used to assess possible structural and chemical changes after dry treatments. Moreover, -3 release profile was studied in ethanol (20 % and 50 % (v/v)) at 25 ÂșC (simulation of food matrices) and at pH 7.4 and pH 2 at 37 ÂșC (simulation of different gastrointestinal phases). DLS results showed that original size (170 nm) and zeta-potential (+30 mV) of nanoemulsions was not achieved after nanospray-drying process probably caused by protein agglomeration. CD and FTIR-ATR results revealed lactoferrin structural modifications after drying processes as well as a reduction of -helix and -sheet content, being this effect more evident on nanospray-drying samples. FTIR-ATR results showed shifts of the amide I and amide II bands in both drying processes samples. At 20 % ethanol, -3 began to release after 48h which could allow nanoemulsions incorporation in food products such as ice cream and mayonnaise. This work provides useful information to design nanoemulsions aiming lipophilic compound encapsulation for food applications.info:eu-repo/semantics/publishedVersio

    Development of bio-based nanoemulsions to improve physical and chemical stability of omega-3 fatty acids

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    The 19th Gums & Stabilisers for the Food Industry Conference: Hydrocolloid MultifunctionalityNowadays there is a high interest of food industry to develop nutritional food products. This concept promoted the development of bio-based structures to encapsulate bioactive compounds and thus enhance their physical and chemical stability during storage until the consumption. In this field nanotechnology can offers several advantages, not only improving water solubility but also in the increase of bioavailability of lipophilic bioactive compounds. Omega-3 polyunsaturated fatty acids (ω-3 fatty acids) are known for their functional properties such as: improving cardiovascular health, decrease inflammation, increase cognitive function, and influence on neurological and visual development. However, ω-3 fatty acids are highly susceptible to oxidation, have an intense odour and present low water solubility, which makes its direct application in foods extremely difficult. In order to reduce these problems, the nanoencapsulation, through the use of nanoemulsions can be used. In this work, Lactoferrin (Lf), a protein derived from milk with a wide range of reported biological activities (e.g. antioxidant, antimicrobial and cancer prevention) was used as natural emulsifier for the development of oil-in-water nanoemulsions. Nanoemulsions were produced with a high-pressure homogenizer applied for 5 cycles at 20000 psi. Different Lf concentrations (0.2; 0.6; 1; 2; 3; 4 and 5% (w/w)) were tested. The nanoemulsions physical properties were evaluated in terms of size and ζ- potential measurements using dynamic light scattering (DLS) and by surface tension using the Ring method. The morphology of nanoemulsions were analysed by transmission electron microscopy (TEM). The physical and chemical stability of these nanoemulsions was assessed during 50 days, at storage temperatures of 4 ÂșC and 25 ÂșC, being the chemical stability of nanoemulsions was evaluated by antioxidant activity measurements using DPPH radical scavenging assay. Results showed that according to the Lf concentration used different properties were obtained. Nanoemulsions with Lf concentrations between 2 and 5% (w/w) presented sizes around 160 nm and a ζ-potential higher than +30 mV. For concentrations below 2 % (w/w), nanoemulsions presented sizes around 200 nm and a ζ- potential bellow +30 mV. It was noticed that higher Lf concentrations lead to smaller sizes and higher ζ-potential values. By increasing the Lf concentration was observed a decrease on superficial tension of nanoemulsions. TEM measurements showed that nanoemulsions particles have defined spherical shape. Results also showed that nanoemulsions with Lf concentration above 2 % (w/w) present better properties (smaller sizes and higher ζ-potential) so the storage stability of these nanoemulsions were assessed. Nanoemulsions stored at 4 ÂșC did not exhibit significant variations in size and ζ-potential values, while at 25 ÂșC the nanoemulsions suffered an size increase (around 35 nm compared to initial value) and a reduction in ζ-potential (around 20 mV compared to initial value) during storage. At these conditions, it was also observed that nanoemulaions with Lf concentrations of 2 and 3 % (w/w) present an instability (variations of size and ζ-potential) after 14 days of storage at 25 ÂșC, while for higher Lf concentrations (4 and 5 % (w/w)) the changes only start to be noticed latter (after 29 days of storage). Antioxidant activity did not demonstrate significant changes before and after storage at both temperatures (IC50 was around 14 mg/g of solution). This work provides important information that can be useful for the design of nanoemulsions aiming the encapsulation of lipophilic compounds for pharmaceutical and food applications.info:eu-repo/semantics/publishedVersio

    Structural approach to design high carotene emulsions from exotic fruits Pitanga (Eugenia uniflora) and Buriti (Mauritia flexuosa)

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    The 19th Gums & Stabilisers for the Food Industry Conference: Hydrocolloid MultifunctionalityThis research seeks to better understand the food matrix microstructure that impacts on carotenoid bioaccessibility of two Brazilian native fruits Pitanga and Buriti while developing emulsioned oral delivery systems of its compounds. Buriti is a fruit produced by an Amazonia palm tree. Its pulp is very rich in ÎČ-carotene which is approximately 400 ”g/g fresh weight1 . Pitanga originates from Atlantic forest and has high amounts of lycopene (approx. 71 ”g/g in ripened fruit)1 . These hydrophobic plant pigments have antioxidant, anti-inflammatory, and anticancer activity. However, these desired health benefits are limited by bioaccessibility aspects, mainly their physical location and structure in fresh fruits and its products2 . Emulsions have been largely studied as oral delivery systems for hydrophobic bioactives compounds such as ÎČ-carotene. Also, the concept of excipient foods is an innovation in food science and technology research2 . Buriti and Pitanga freeze dried pulps were submitted to the following experiments: 1) experimental design testing ultraturrax and ultrasound for carotene release; 2) emulsion formation by Tween 80 or Whey Protein Isolate at 1 % and 2 % surfactant concentration; 3) microstructure study of fresh pulps and emulsions. For carotene determination, it was applied a microscale extraction and HPLC-PDA analysis based on Porcu and Rodriguez-Amaya (2008)3 . Processed pulp and fruit emulsions microstructure was assessed by microscopy (brightfield, fluorescence and confocal), rheology and turbidity. Main results showed that ultrasound processing have more impact on tissue fragmentation, cell disruption and carotene release than ultraturrax (p<0.05) and is indispensable for fruit emulsion formation. Microscopy study clearly elucidate that most carotenes are entrapped inside cell walls and must be released for incorporation into lipid micelles. Ultraturrax (15000 rpm) and ultrasound (20 kHz, 40 % amplitude) treatment released up to 50 % of initial carotenoid. After emulsion formation, surfactant do not link only to the internal oil and external water, it also interacts with the carbohydrate from cell walls mainly cellulose that are in suspension – forming a gel-like structure – that was demonstrated by confocal microscopy. The obtained Buriti and Pitanga emulsions have high potential for the development new products with more bioaccessible ÎČ-carotene and lycopene.info:eu-repo/semantics/publishedVersio
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