Encapsulation of hydrophobic compounds in microgels

Orientador: Rosiane Lopes da CunhaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: A microencapsulação é uma técnica que vem sendo amplamente estudada para a proteção de compostos bioativos e controle de sua liberação. Neste contexto, o objetivo geral deste trabalho foi produzir micropartículas através da extrusão de emulsões estabilizadas por biopolímeros (caseinato de sódio e ?-carragena) em solução de cloreto de potássio para a encapsulação de compostos hidrofóbicos. Na primeira parte deste estudo, o processo de extrusão em um atomizador foi estudado através da produção de microgéis a partir de soluções aquosas de caseinato de sódio (Na-CN) e ?-carragena. Os efeitos da vazão de alimentação, vazão de ar comprimido no bico atomizador, viscosidade e tensão superficial das soluções foram avaliados experimentalmente e através da análise de parâmetros adimensionais. Os resultados mostraram que os menores microgéis foram obtidos com a menor vazão de alimentação, menor viscosidade da solução biopolimérica e maior vazão de ar comprimido. No entanto, a esfericidade dos microgéis foi principalmente influenciada pela tensão superficial das soluções. Na segunda etapa do trabalho, emulsões óleo-água (O/A) multicamadas estabilizadas por caseinato de sódio e ?-carragena foram estudadas com o intuito de determinar as condições de maior estabilidade em pH 7 e 3,5. Em pH 7, o fenômeno de floculação por depleção ocorreu em elevada concentração de ?-carragena, enquanto que em pH 3,5 foi observada a floculação por ponte (bridging flocculation) em menores concentrações de polissacarídeo. Emulsões estáveis foram produzidas na maior concentração de polissacarídeo (1% m/v) em ambos os valores de pH (7 e 3,5) devido ao aumento da viscosidade da fase contínua. Na terceira parte do estudo, microesferas com potencial para encapsulação de compostos hidrofóbicos foram produzidas a partir da gelificação iônica das emulsões multicamadas e avaliadas quanto à estabilidade em diferentes meios. As microesferas produzidas em pH 3,5 foram mais estáveis do que aquelas preparadas em pH 7, sendo que ambas foram altamente estáveis quando dispersas em soluções de cloreto de potássio com concentrações superiores a 0,75% (m/v). Na última etapa do trabalho foi avaliado um exemplo de aplicação das microesferas para encapsulação de triptofano. Nesta etapa, as propriedades reológicas de suspensões de microgéis também foram estudadas com o intuito de verificar a sua influência na textura dos produtos. A eficiência de encapsulação do triptofano nas microesferas foi baixa (~30%), o que pode ser explicado pelo elevado tamanho dos poros do gel que não impediu a difusão desse composto de baixa massa molecular. No entanto, a liberação do bioativo foi bastante baixa quando as micropartículas foram diluídas em solução aquosa. Além disso, suspensões de microesferas com menores diâmetros e formatos mais esféricos apresentaram pouca influência na textura, mostrando sua potencial aplicação em produtos contendo elevada quantidade de águaAbstract: Microencapsulation is a technique widely used for the protection of bioactive compounds and for controlling their release. In this context, the general purpose of this work was to produce microbeads through the extrusion of biopolymer-stabilized emulsions (sodium caseinate and ?-carrageenan) in a potassium chloride solution, aiming the encapsulation of hydrophobic compounds. In the first part of this work, the extrusion process was studied in an atomizer, producing microgels from aqueous solution of sodium caseinate (Na-CN) and ?-carrageenan. The effect of feed flow rate and compressed air flow rate in the atomizer nozzle, viscosity and surface tension of solutions were evaluated experimentally and through the analysis of dimensionless parameters. The results showed that smaller microgels were produced using lower feed flow rate, lower viscosity and higher compressed air flow rate. Nevertheless, the sphericity of microgels was mainly influenced by the surface tension of solutions. In the second step of this work, oil-in-water (O/W) multilayered emulsions stabilized by sodium caseinate and ?-carrageenan were studied in order to determine the conditions of higher stability at pH 7 and 3.5. At pH 7, depletion flocculation occurred at high ?-carrageenan concentrations, while at pH 3.5, bridging flocculation was observed at lower polysaccharide concentrations. Stable emulsions were produced in the highest polysaccharide concentration (1% w/v) in both pH values (7 and 3.5) due to the increase of viscosity of the continuous phase. In the third part of this study, microbeads potentially useful for encapsulation of hydrophobic compounds were produced by ionic gelation of multilayered emulsions and evaluated in relation to stability in different media. The microbeads produced at pH 3.5 were more stable than those prepared at pH 7 and both were highly stable when dispersed in solutions with more than 0.75% (w/v) potassium chloride. In the last step of this study, an example of microbead application for encapsulating tryptophan was evaluated. In this step, the rheological properties of suspensions of microgels were also studied in order to verify their influence on the texture of products. The encapsulation efficiency of tryptophan in the microbeads was low (~30%), which was attributed to the large pore size of the gel matrix that could not hinder the diffusion of this low molecular weight compound. However, the release of bioactive was very low when the particles were diluted in aqueous solution. Moreover, suspensions of microbeads with smaller diameters and more spherical shape showed little influence on the texture, exhibiting their potential application in products with high water contentDoutoradoEngenharia de AlimentosDoutor em Engenharia de Alimento

Interfacial energy during the emulsification of water-in-heavy crude oil emulsions

The aim of this study was to investigate the interfacial energy involved in the production of water-in-oil (W/O) emulsions composed of water and a Brazilian heavy crude oil. For such purpose an experimental set-up was developed to measure the different energy terms involved in the emulsification process. W/O emulsions containing different water volume fractions (0.1, 0.25 and 0.4) were prepared in a batch calorimeter by using a high-shear rotating homogenizer at two distinct rotation speeds (14000 and 22000 rpm). The results showed that the energy dissipated as heat represented around 80% of the energy transferred to the emulsion, while around 20% contributed to the internal energy. Only a very small fraction of the energy (0.02 - 0.06%) was stored in the water-oil interface. The results demonstrated that the high energy dissipation contributes to the kinetic stability of the W/O emulsions321127137CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESThe authors are grateful to PETROBRAS S.A. and FINEP, Brazil, for the financial support to this study. We also acknowledge the grants conceded by CAPES and CNPq, Brazi

Structural and rheological evaluation of simple and multiple emulsions stabilized by sodium caseinate and LGB

Orientador: Rosiane Lopes da CunhaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Proteínas e polissacarídeos são amplamente utilizados em emulsões alimentícias como agentes emulsificantes e estabilizantes. Entretanto, a presença de ambos biopolímeros em solução aquosa pode resultar no processo de separação de fases, dependendo das condições de pH e força iônica empregadas. Esse estudo mostrou que é possível a produção de diferentes tipos de emulsões múltiplas através da mistura de emulsões óleo-água (O/A) com uma mistura de biopolímeros de fases separadas. Inicialmente, foram estudadas as propriedades de emulsões óleo água (O/A) estabilizadas por caseinato de sódio (Na-CN) sob diferentes condições de acidificação e aplicação de pressão, além das emulsões estabilizadas por Na-CN e goma jataí (LBG). A maioria das emulsões apresentou separação de fases devido ao mecanismo de cremeação, porém este processo de desestabilização foi reduzido quando existiu o aumento da viscosidade dos sistemas ou a diminuição do tamanho das gotas. A viscosidade das emulsões foi modificada pela adição de maiores concentrações de óleo e biopolímeros, e pela redução do pH em direção ao ponto isoelétrico da proteína. Já a redução do tamanho das gotas foi realizada através de aplicação de altas pressões. A homogeneização a altas pressões promoveu a formação de emulsões com tamanhos de gotas muito reduzidos (entre 0,39 e 1,50 mm), sendo possível a sua utilização para o preparo das emulsões múltiplas. Em uma segunda etapa do trabalho, um diagrama de fases foi construído para identificar a faixa de concentrações de Na-CN e LBG que resultariam em uma solução de fases separadas, bem como as condições de pH e força iônica necessárias para o processo de separação de fases. Assim, as soluções mistas Na-CN ¿ LBG formaram uma fase inferior rica em Na-CN (A1) e uma fase superior rica em LBG (A2), sendo possível a formação de emulsões água-água (A1/A2 ou A2/A1) através da mistura das fases superior e inferior em diferentes razões. A mistura de uma emulsão O/A estabilizada por Na-CN e homogeneizada a alta pressão, com soluções de fases separadas compostas pelas mesmas razões de fase superior e inferior utilizadas no preparo das emulsões A/A resultou na formação de emulsões múltiplas. Estas emulsões foram do tipo óleo-água-água (O/A1/A2) ou do tipo óleo-água/água-água (O/A1-A2/A1), dependendo da composição inicial de biopolímeros no sistemaAbstract: Proteins and polysaccharides are widely used in food emulsions as emulsifying and stabilizing agents. However, the mixture of both biopolymers in an aqueous solution can lead to a phase separation process, depending on the conditions of pH and ionic strength. This study showed that multiple emulsions can be prepared by mixing an oil-in-water (O/W) emulsion with a mixed biopolymer solution that separates into two phases. Initially, the oil-in-water emulsions (O/W) stabilized by sodium caseinate were studied at different conditions of acidification and high-pressure homogenization. Emulsions stabilized by Na-CN and LBG were also studied. Most of the emulsions showed phase separation due to the creaming mechanism, but this destabilization process was reduced with the increase of system viscosity and the decrease of oil droplet size. The emulsion viscosity was changed by addition of greater oil and biopolymer concentrations and by reduction of pH in direction to protein¿s isoelectric point, while reduction of droplet size was obtained by application of high pressure. The high-pressure homogenization promoted the formation of very small droplets (between 0.39 and 1.5 mm), which favored the production of multiple emulsions. In a second step of this work, a phase diagram was constructed to identify the range of sodium caseinate (Na-CN) and locust bean gum (LBG) concentrations where phase separation occurred and the conditions of pH and ionic strength that led to the incompatibility between them. Thus, in this conditions, the Na-CN ¿ LBG mixed solution formed a two-phase system consisting of a Na-CN ¿ enriched lower phase (W1) and a LBG ¿ enriched upper phase (W2). Water-in-water emulsions (W1/W2 or W2/W1) could be formed by blending incompatible upper and lower phases together at different ratios. Thus, multiple emulsions were prepared by mixing the O/W emulsions homogenized at high-pressure with the same incompatible solutions used to prepare the W/W emulsions. The produced multiple emulsions were the oil-in-water-in water (O/W1/W2) type or the mixed oil-in-water/water-in-water (O/W1 - W2/W1) type depending on the initial biopolymer composition of the systemMestradoMestre em Engenharia de Alimento

New functionalities of Maillard reaction products as emulsifiers and encapsulating agents, and the processing parameters: a brief review

Non-enzymatic browning has been a wide and interesting research area in the food industry, ranging from the complexity of the reaction to its applications in the food industry as well as its ever-debatable health effects. This review provides a new perspective to the Maillard reaction apart from its ubiquitous function in enhancing food flavour, taste and appearance. It focuses on the recent application of Maillard reaction products as an inexpensive and excellent source of emulsifiers as well as superior encapsulating matrices for the entrapment of bioactive compounds. Additionally, it will also discuss the latest approaches employed to perform the Maillard reaction as well as several important reaction parameters that need to be taken into consideration when conducting the Maillard reaction

Protein-based structures for food applications: from macro to nanoscale

Novel food structures' development through handling of macroscopic and microscopic properties of bio-based materials (e.g., size, shape, and texture) is receiving a lot of attention since it allows controlling or changing structures' functionality. Proteins are among the most abundant and employed biomaterials in food technology. They are excellent candidates for creating novel food structures due to their nutritional value, biodegradability, biocompatibility, generally recognized as safe (GRAS) status and molecular characteristics. Additionally, the exploitation of proteins' gelation and aggregation properties can be used to encapsulate bioactive compounds inside their network and produce consistent delivery systems at macro-, micro-, and nanoscale. Consequently, bioactive compounds which are exposed to harsh storage and processing conditions and digestion environment may be protected and their bioavailability could be enhanced. In this review, a range of functional and structural properties of proteins which can be explored to develop macro-, micro-, and nanostructures with numerous promising food applications was discussed. Also, this review points out the relevance of scale on these structures' properties, allowing appropriate tailoring of protein-based systems such as hydrogels and micro- or nanocapsules to be used as bioactive compounds delivery systems. Finally, the behavior of these systems in the gastrointestinal tract (GIT) and the impact on bioactive compound bioavailability are thoroughly discussed.JM and AP acknowledge the Portuguese Foundation for Science and Technology (FCT) for their fellowships (SFRH/BPD/89992/2012 and SFRH/BPD/101181/2014). This work was supported by Portuguese FCT under the scope of the Project PTDC/AGR-TEC/5215/2014, of the strategic funding of UID/BIO/04469 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Stabilization Of Multilayered Emulsions By Sodium Caseinate And κ-carrageenan

The influence of the κ-carrageenan concentration and pH on the properties of oil-in-water multilayered emulsions was studied. Multilayered emulsions were prepared by the mixture of a primary emulsion stabilized by 0.5% (w/v) sodium caseinate (Na-CN) with κ-carrageenan solutions with different concentrations (0.05-1% w/v). The emulsions were evaluated at pH 7 and 3.5. At pH 7, there was little adsorption of κ-carrageenan onto the droplet surface and a depletion flocculation was observed when the polysaccharide concentration exceeded 0.5% (w/v). At pH 3.5, a mixed κ-carrageenan-Na-CN second layer was formed around the protein-covered droplets and the emulsions showed bridging flocculation at lower polysaccharide concentrations (0.05-0.25% w/v). Stable emulsions could be formed with the highest κ-carrageenan concentration (1% w/v) at both pH values (7.0 and 3.5). Thus, stable emulsions were successfully produced using protein-polysaccharide interfacial complexes, and the oil droplet diameter, zeta potential and rheological properties of these emulsions were not affected by changes in the pH. © 2012 Elsevier Ltd.302606613(1996) Official method of analysis, , AOAC, Association of Official Analytical Chemists, WashingtonArltoft, D., Ipsen, R., Madsen, F., de Vries, J., Interactions between carrageenans and milk proteins: a microstructural and rheological study (2007) Biomacromolecules, 8 (2), pp. 729-736Berli, C.L.A., Quemada, D., Parker, A., Modelling the viscosity of depletion flocculated emulsions (2002) Colloids and Surfaces A: Physicochemical and Engineering Aspects, 203, pp. 11-20Bouyer, E., Mekhloufi, G., Le Potier, I., de Kerdaniel, T.D., Grossiord, J.L., Rosilio, V., Stabilization mechanism of oil-in-water emulsions by β-lactoglobulin and gum arabic (2011) Journal of Colloid and Interface Science, 354 (2), pp. 467-477Cho, Y.H., McClements, D.J., Theoretical stability maps for guiding preparation of emulsions stabilized by protein-polysaccharide interfacial complexes (2009) Langmuir, 25 (12), pp. 6649-6657De Ruiter, G.A., Rudolph, B., Carrageenan biotechnology (1997) Trends in Food Science & Technology, 8 (12), pp. 389-395Dickinson, E., Golding, M., Depletion flocculation of emulsions containing unadsorbed sodium caseinate (1997) Food Hydrocolloids, 11 (1), pp. 13-18Dickinson, E., Golding, M., Povey, M.J.W., Creaming and flocculation of oil-in-water emulsions containing sodium caseinate (1997) Journal of Colloid and Interface Science, 185 (2), pp. 515-529Dickinson, E., Semenova, M.G., Antipova, A.S., Salt stability of casein emulsions (1998) Food Hydrocolloids, 12 (2), pp. 227-235Dubois, M., Gilles, K.A., Hamilton, J.K., Rebers, P.A., Smith, F., Colorimetric method for determination of sugar and related substances (1956) Analytical Chemistry, 28 (3), pp. 350-356Garti, N., What can nature offer from an emulsifier point of view: trends and progress? 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Williams (Eds.)Jourdain, L., Leser, M.E., Schmitt, C., Michel, M., Dickinson, E., Stability of emulsions containing sodium caseinate and dextran sulfate: relationship to complexation in solution (2008) Food Hydrocolloids, 22 (4), pp. 647-659Kato, A., Mifuru, R., Matsudomi, N., Kobayashi, K., Functional casein-polysaccharide conjugates prepared by controlled dry heating (1992) Bioscience, Biotechnology, and Biochemistry, 56 (4), pp. 567-571Keowmaneechai, E., McClements, D.J., Influence of EDTA and citrate on physicochemical properties of whey protein-stabilized oil-in-water emulsions containing CaCl 2 (2002) Journal of Agricultural and Food Chemistry, 50 (24), pp. 7145-7153Kinsella, J.E., Morr, C.V., Milk proteins: physicochemical and functional properties (1984) Critical Reviews in Food Science and Nutrition, 21 (3), pp. 197-262Langendorff, V., Cuvelier, G., Launay, B., Parker, A., Gelation and flocculation of casein micelle/carrageenan mixtures (1997) Food Hydrocolloids, 11 (1), pp. 35-40Liu, L., Zhao, Q., Liu, T., Kong, J., Long, Z., Zhao, M., Sodium caseinate/carboxymethylcellulose interactions at oil-water interface: relationship to emulsion stability (2012) Food Chemistry, 132 (4), pp. 1822-1829Martin, A.H., Goff, H.D., Smith, A., Dalgleish, D.G., Immobilization of casein micelles for probing their structure and interactions with polysaccharides using scanning electron microscopy (SEM) (2006) Food Hydrocolloids, 20 (6), pp. 817-824McClements, D.J., Protein-stabilized emulsions (2004) Current Opinion in Colloid & Interface Science, 9 (5), pp. 305-313McClements, D.J., (2005) Food emulsions: Principles, practice and techniques, , CRC Press, New YorkMena-Casanova, E., Totosaus, A., Improvement of emulsifying properties of milk proteins with κ or λ carrageenan: effect of pH and ionic strength (2011) International Journal of Food Science and Technology, 46 (3), pp. 535-541Oliver, C.M., Melton, L.D., Stanley, R.A., Creating proteins with a novel functionality via the Maillard reaction: a review (2006) Critical Reviews in Food Science and Nutrition, 46 (4), pp. 337-350O'Regan, J., Mulvihill, D.M., Heat stability and freeze-thaw stability of oil-in-water emulsions stabilized by sodium caseinate-maltodextrin conjugates (2010) Food Chemistry, 119 (1), pp. 182-190Pallandre, S., Decker, E.A., McClements, D.J., Improvement of stability of oil-in-water emulsions containing caseinate-coated droplet by addition of sodium alginate (2007) Journal of Food Science, 72 (9), pp. E518-E524Perrechil, F.A., Cunha, R.L., Oil-in-water emulsions stabilized by sodium caseinate: influence of pH, high-pressure homogenization and locust bean gum addition (2010) Journal of Food Engineering, 97 (4), pp. 441-448Singh, H., Tamehana, M., Hemar, Y., Munro, P.A., Interfacial compositions, microstructures and properties of oil-in-water emulsions formed with mixtures of milk proteins and κ-carrageenan: 1. 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Acid gelation of native and heat-denatured soy proteins and locust bean gum

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The effects of protein concentration and locust bean gum (LBG) addition on the mechanical properties, microstructure and water holding capacity of acidified soy protein (SPI) gels were studied. The protein was employed in two different states: (i) native and (ii) heat denatured. A slow acidification rate was induced in both systems by applying glucono-d-lactone (GDL). The results indicated that the gels of native SPI were weaker, less deformable and showed lower water holding capacity than the gels of heat-denatured SPI. The LBG addition led to an increase in the strength and water holding capacity of SPI gels, independent of the protein state (native or denatured). These results indicated that the properties of texture and water holding capacity of the SPI acid gels can be modulated by the process conditions or by the addition of other ingredients, such as polysaccharides.483620627Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2004/08517-3]CNPq [301869/2006-5, 477620/2003-5

Development of multiple emulsions based on the repulsive interaction between sodium caseinate and LBG

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The stability of oil-in-water, water-in-water and multiple emulsions containing sodium caseinate (Na-CN) and/or locust bean gum (LBG) at pH 5.5 was investigated with different compositions using a visual analysis (creaming and/or phase separation), optical microscopy and rheological measurements. Oil-in-water emulsions (O/W) were produced by high pressure homogenization, which promoted the formation of very small droplets (similar to 0.4 mu m) and hindered the destabilization process. In the second step of this study, a visual phase diagramwas constructed in order to identify the concentrations of sodium caseinate (Na-CN) and locust bean gum (LBG) that led to phase separation at pH 5.5. A mixed solution composed of 3% (w/v) Na-CN and 0.3% (w/v) LBG was chosen to produce the water-in-water and multiple emulsions. After centrifugation, the solution was separated into an upper phase rich in polysaccharide (PS) and a bottom phase rich in protein (PR), which were mixed in different proportions (1:3, 1:1, 3:1), forming the water-in-water (W/W) emulsions. The stability, microstructure and rheological properties of the W/W emulsions depended strongly on the composition of the biopolymers. An increase in the polysaccharide concentration in the W/W emulsions led to the production of more viscous and stable systems. Multiple emulsions with different characteristics were prepared and also depended on the biopolymer composition. The system with the highest polysaccharide content was the only one that showed an O/W/W structure, while the others presented the microstructure of an O/W-W/W emulsion. (C) 2011 Elsevier Ltd. All rights reserved.261126134Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2006/02318-4, 2007/58017-5]CNPq [301869/2006-5