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1.
J Sci Food Agric ; 103(8): 4195-4202, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36637051

RESUMO

BACKGROUND: Binders in plant-based meat analogues allow different components, such as extrudate and fat particles, to stick together. Typically, binders then are solidified to transform the mass into a non-sticky, solid product. As an option for a clean-label binder possessing such properties, the solidification behavior of pea protein-pectin mixtures (250 g kg-1 , r = 2:1, pH 6) was investigated upon heating, and upon addition of calcium, transglutaminase, and laccase, or by combinations thereof. RESULTS: Mixtures of (homogenized) pea protein and apple pectin had higher elastic moduli and consistency coefficients and lower frequency dependencies upon calcium addition. This indicated that calcium physically cross-linked pectin chains that formed the continuous phase in the biopolymer matrix. The highest degree of solidification was obtained with a mixture of pea protein and sugar beet pectin upon addition of laccase that covalently cross-linked both biopolymers involved. All solidified mixtures lost their stickiness. A mixture of soluble pea protein and apple pectin solidified only slightly through calcium and transglutaminase, probably due to differences in the microstructural arrangement of the biopolymers. CONCLUSION: The chemical makeup of the biopolymers and their spatial distribution determines solidification behavior in concentrated biopolymer mixtures. In general, pea protein-pectin mixtures can solidify and therefore have the potential to act as binders in meat analogues. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Proteínas de Ervilha , Pectinas , Pectinas/química , Cálcio , Lacase/química , Biopolímeros/química
2.
J Food Sci ; 87(10): 4622-4635, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36103208

RESUMO

Foams are essential in many food applications and require surface-active ingredients such as proteins for formation and stabilization. We investigated the influence of high-pressure homogenization on foaming properties of insoluble pea protein dispersions (5% w/w) at pH 3 and 5. Unhomogenized insoluble pea protein dispersions did not foam at either pH 3 or 5, as they consisted of large insoluble pea protein aggregates with limited surface activity. At pH 3, the homogenized pea protein dispersions generated foams due to higher protein solubility and surface activity through disruption of large protein aggregates into smaller particles. The foam stability decreased with increasing homogenization pressure and number of cycles due to a reduction in continuous phase viscosity. At pH 5, the insoluble pea proteins foamed when the homogenization resulted in formation of aggregates made of smaller protein entities, which was the case for homogenization ≥ 100 MPa and three cycles. In general, the foam capacity (amount of formed foam) was higher at pH 3 due to improved protein solubility and surface activity that facilitated incorporation of air, while the foam stability (resistance against foam collapse) was better at pH 5 because of the presence of larger protein aggregates that formed thicker and more viscous films around the air bubbles benefitting retention of gas bubbles. Overall, homogenization improved the foaming properties of insoluble pea proteins at pH 3 and 5. Practical Application Insoluble pea protein dispersions formed foams at pH 3 and 5 after homogenization highlighting the potential of this processing step for the food industry. The improvement in functionality of plant-derived ingredients helps to increase their use for consumer goods, thereby supporting the transition to more sustainable food system.


Assuntos
Proteínas de Ervilha , Agregados Proteicos , Concentração de Íons de Hidrogênio , Viscosidade , Solubilidade
3.
Rev Bras Enferm ; 75(6): e2022v75n6refl, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35319569

RESUMO

OBJECTIVE: To reflect on how human resource health managers and talent managers may engage and retain experienced nursing professionals in Brazil. METHODS: Reflection based on studies on global and Brazilian-specific nursing professionals and retention, before and during the COVID-19 pandemic. RESULTS: The pandemic worsened working conditions for all health professionals. Nursing professionals were particularly affected. Nurses have been viewed as "heroes" and "essential" frontline workers during the COVID-19 pandemic. However, despite the universal praise for their efforts, it seems uncertain if they were actually considered and managed like talent. FINAL CONSIDERATIONS: In order to develop a sustainable healthcare system supported by sufficient experienced nursing talent, healthcare human resource managers and talent managers must develop and implement impactful nursing talent retention and engagement strategies. We highlight possible strategies targeting experienced nursing talent that will help to sustain the Brazilian healthcare system, post-pandemic.


Assuntos
COVID-19 , Pandemias , Brasil , Atenção à Saúde , Humanos , Recursos Humanos
4.
Foods ; 12(1)2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36613300

RESUMO

A bacon-type meat analogue consists of different structural layers, such as textured protein and a fat mimetic. To obtain a coherent and appealing product, a suitable binder must glue those elements together. A mixture based on pea protein and sugar beet pectin (r = 2:1, 25% w/w solids, pH 6) with and without laccase addition and a methylcellulose hydrogel (6% w/w) serving as benchmark were applied as binder between textured protein and a fat mimetic. A tensile strength test, during which the layers were torn apart, was performed to measure the binding ability. The pea protein-sugar beet pectin mixture without laccase was viscoelastic and had medium and low binding strength at 25 °C (F ≤ 3.5 N) and 70 °C (F ≈ 1.0 N), respectively. The addition of laccase solidified the mixture and increased binding strength at 25 °C (F ≥ 4.0 N) and 70 °C (F ≈ 2.0 N), due to covalent bonds within the binder and between the binder and the textured protein or the fat mimetic layers. Generally, the binding strength was higher when two textured protein layers were glued together. The binding properties of methylcellulose hydrogel was low (F ≤ 2.0 N), except when two fat mimetic layers were bound due to hydrophobic interactions becoming dominant. The investigated mixed pectin-pea protein system is able serve as a clean-label binder in bacon-type meat analogues, and the application in other products seems promising.

5.
Rev. bras. enferm ; 75(6): e2022v75n6refl, 2022.
Artigo em Inglês | LILACS-Express | LILACS, BDENF - Enfermagem | ID: biblio-1365642

RESUMO

ABSTRACT Objective: To reflect on how human resource health managers and talent managers may engage and retain experienced nursing professionals in Brazil. Methods: Reflection based on studies on global and Brazilian-specific nursing professionals and retention, before and during the COVID-19 pandemic. Results: The pandemic worsened working conditions for all health professionals. Nursing professionals were particularly affected. Nurses have been viewed as "heroes" and "essential" frontline workers during the COVID-19 pandemic. However, despite the universal praise for their efforts, it seems uncertain if they were actually considered and managed like talent. Final considerations: In order to develop a sustainable healthcare system supported by sufficient experienced nursing talent, healthcare human resource managers and talent managers must develop and implement impactful nursing talent retention and engagement strategies. We highlight possible strategies targeting experienced nursing talent that will help to sustain the Brazilian healthcare system, post-pandemic.

6.
J Clin Nurs ; 30(15-16): 2420-2430, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34010457

RESUMO

AIM AND OBJECTIVES: To investigate how organisational and individual resources are linked to older (50+) nursing professionals' organisational commitment, and to examine the possible mediating role of the active use of selection, optimisation and compensation (SOC) strategies. BACKGROUND: Many healthcare organisations need to find ways to retain their older nursing professionals due to nursing shortage. DESIGN: To test a set of hypotheses, cross-sectional survey data (n = 396) were used. Data were analysed using correlation analysis and partial least-squares structural equation modelling. STROBE Statement for cross-sectional studies has been followed in this study. RESULTS: The results exhibited that both individual and organisational resources and the active use of SOC strategies were positively associated with older nursing professionals' organisational commitment. The active use of SOC strategies had a partially mediating role in the relationship between individual resource (career management self-efficacy) and organisational commitment. Similarly, career management self-efficacy partially mediated the association between organisational resources (perceived high-involvement work practices) and organisational commitment. CONCLUSIONS: Regarding the retention of older nursing professionals, attention should be paid to both individual and organisational resources and the active use of SOC strategies. RELEVANCE FOR CLINICAL PRACTICE: By providing opportunities to actively use SOC strategies and by paying attention to career management self-efficacy among older nursing professionals, nursing managers may influence the retention of the older nursing workforce. Similarly, supportive organisational practices can support older nursing professionals' career management self-efficacy and their organisational commitment.


Assuntos
Salários e Benefícios , Autoeficácia , Estudos Transversais , Humanos , Satisfação no Emprego , Inquéritos e Questionários
7.
J Agric Food Chem ; 68(50): 15027-15035, 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33259191

RESUMO

An LC-MS/MS method was developed for the simultaneous quantitative analysis of the following 11 triterpene saponins within different sugar beet materials and plant compartments: betavulgaroside I (1), betavulgaroside II (2), betavulgaroside III (3), betavulgaroside IV (4), betavulgaroside VIII (5), boussingoside A2 (6), 3-O-[ß-d-glucopyranosyl-(1 → 2)-(ß-d-xylopyranosyl-(1 → 3))-ß-d-glucuronopyranosyl]-28-O-ß-d-glucopyranosyl-3ß-hydroxyolean-12-en-28-oic acid (7), betavulgaroside V (8), chikusetsusaponin IVa (9), calenduloside E (10), and ginsenoside R0 (11). Our results showed highly varying amounts of saponins within different varieties, roots, and leaves as well as different plant compartments. The amounts for sugar beet roots were in the range of 862 mg/kg to 2 452 mg/kg. They were mostly higher for leaves compared to roots of the same variety with amounts ranging from 907 mg/kg to 5 398 mg/kg. Furthermore, the occurrence of sugar beet saponins within different side streams was examined; in this context, sugar beet fiber contained the highest amounts of saponins for all investigated plant constituents and byproduct streams with a total amount of 12.7 g/kg. Finally, this is the first publication about the occurrence of individual saponins in sugar beets.


Assuntos
Beta vulgaris/química , Cromatografia Líquida de Alta Pressão/métodos , Extratos Vegetais/química , Saponinas/química , Espectrometria de Massas em Tandem/métodos , Beta vulgaris/classificação , Glicosídeos/química , Estrutura Molecular , Folhas de Planta/química , Raízes de Plantas/química , Triterpenos/química
8.
J Agric Food Chem ; 68(39): 10962-10974, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-32881499

RESUMO

This work focuses on the isolation and characterization of saponins with a very low bitter intensity originating from sustainable plant materials, in particular the sugar beet pulp by-product stream. Via a concise foam activity screening of saponin-containing materials, which gives indications for their emulsifying ability, sugar beet root extract was selected and examined for low bitter saponins by means of activity guided fractionation. Individual saponins were isolated from sugar beet pulp, which was identified as the most convenient sugar beet saponin source. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis and one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy led to the unequivocal identification of the major, slightly bitter tasting compounds as a series of eight saponins. The complete assignment of 1H and 13C NMR signals for several saponins was carried out for the first time. A small-scale foam activity assay was established and applied to a broad spectrum of the isolated and commercially available saponins. Additionally, orosensory recognition thresholds were determined. Not only high recognition thresholds were determined (thresholds >1000 µmol/L) but also fundamental information about the foaming behavior of mono- and bidesmosidic saponins was collected. The obtained results are relevant to the utilization of saponins from other plant materials or by-product streams and for the use of sugar beet saponins as food additives.


Assuntos
Beta vulgaris/química , Aromatizantes/química , Extratos Vegetais/química , Saponinas/química , Cromatografia Líquida , Estrutura Molecular , Tubérculos/química , Espectrometria de Massas em Tandem , Resíduos/análise
9.
Food Chem ; 327: 127087, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454277

RESUMO

This study investigated the lipid oxidation reactions of furan fatty acids, long-chain ω-3 polyunsaturated fatty acids, and tocopherols in an enriched ω-3 fish oil to better understand their degradation kinetics. Furthermore, the influence of an added monomethyl furan fatty acid 9-(3-methyl-5-pentylfuran-2-yl) nonanoic acid (9M5) at 50-250 µM on the oxidation reactions was evaluated. The results showed that the fish oil was rich in monomethyl and dimethyl furan fatty acids (c = 1.3 g/100 g lipids). Upon oxidation of the fish oil, the dimethyl furan fatty acids degraded faster than the monomethyl ones, but also faster than tocopherols. The addition of 9M5 revealed antioxidant activity: It inhibited the degradation of the ω-3 polyunsaturated fatty acids and the formation of primary and secondary lipid oxidation products, and slowed down the degradation of the furan fatty acids and tocopherols. This research offers new insights into the importance of furan fatty acids in lipid oxidation reactions.


Assuntos
Antioxidantes/química , Ácidos Graxos Ômega-3/química , Óleos de Peixe/química , Furanos/química , Ácidos Graxos/química , Cinética , Oxirredução , Tocoferóis/química
10.
J Food Sci ; 85(4): 1213-1222, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32249411

RESUMO

Knowledge of binary emulsifiers' influence on the formation and stability of emulsion-based products is still limited. The aim of this study was to investigate the emulsifying properties of Quillaja saponin-egg lecithin mixtures at different concentration ratios (r = 5:0, 4:1, 3:2, 2:3, 1:4, and 0:5) with total emulsifier concentration set to 0.5% or 1.0% (w/w). For this, oil-in-water emulsions (10% oil, pH 7) were prepared via high-pressure homogenization. Furthermore, emulsion stability against different environmental stresses was tested. All the binary emulsifier mixtures formed submicron sized emulsions upon homogenization. The most stable emulsions among the mixed emulsifiers were obtained at low Quillaja saponin concentration at r = 1:4 that showed similar physical stability over time to emulsions stabilized by Quillaja saponins and egg lecithin alone. The data suggested that the mixtures of Quillaja saponins and egg lecithins built mixed interfacial layers that were prone to changes over time. Emulsions stabilized by the binary mixtures were in general less stable against changes in pH and ionic strength than the emulsions stabilized by the individual emulsifiers. An exception were the emulsions at r = 1:4 that showed improved stability at pH 2 over the phase separated Quillaja saponin-stabilized emulsions at the same pH. Moreover, all the emulsions were heat stable up to 90 °C. On the other hand, none of the emulsions were stable upon freeze-thawing. These results increase our understanding of technofunctionality of binary emulsifier systems. PRACTICAL APPLICATION: Food-grade and natural emulsifier mixtures composed of Quillaja saponins and egg lecithin may be used in selected emulsion-based food or personal care product applications to replace synthetic surfactants due to issues with consumer acceptance and regulatory restrictions.


Assuntos
Lecitinas/química , Extratos Vegetais/química , Quillaja/química , Emulsificantes/química , Emulsões/química , Concentração Osmolar , Tamanho da Partícula , Saponinas de Quilaia/química , Tensoativos/química
11.
Adv Colloid Interface Sci ; 271: 101987, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31325651

RESUMO

Mixed protein-polysaccharide structures have found widespread applications in various fields, such as in foods, pharmaceuticals or personal care products. A better understanding and a more precise control over the molecular interactions between the two types of macromolecules leading to an engineering of nanoscale and colloidal building blocks have fueled the design of novel structures with improved functional properties. However, these building blocks often do not constitute the final matrix. Rather, further process operations are used to transform the initially formed structural entities into bulk matrices. Systematic knowledge on the relation between molecular structure design and subsequent mesoscopic scale transitions induced by processing is scarce. This article aims at establishing a connection between these two approaches. Therefore, it reviews not only studies on the underlying molecular interaction phenomena leading to either a segregative or associative phase behavior and nanoscale or colloidal structures, but also looks at the less systematically studied approach of using macroscopic processing operations such as shearing, heating, crosslinking, and concentrating/drying to transform the initially generated structures into bulk matrices. Thereby, a more comprehensive look is taken at the relationship between different influencing factors, namely solvent conditions (i.e. pH, ionic strength), biopolymer characteristics (i.e. type, charge density, mixing ratio, biopolymer concentration), and processing parameters (i.e. temperature, mechanical stresses, pressure) to generate bulk protein-polysaccharide matrices with different morphological features. The need for a combinatorial approach is then demonstrated by reviewing in detail current mixed protein-polysaccharide applications that increasingly make use of this. In the process, open scientific questions that will need to be addressed in the future are highlighted.

12.
Food Res Int ; 119: 741-750, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30884711

RESUMO

This study investigated spray drying of food-grade solid lipid particles (SLN) and nanostructured lipid carriers (NLC) containing ω-3 fish oil. Stable SLN and NLC dispersions with tristearin as carrier lipid were formed by using a combination of Quillaja saponins and high-melting lecithin as emulsifiers. Our specific goal was to study the influence of four different spray drying inlet and outlet temperatures (Tinlet/outlet = 140-170 °C/65-95 °C) and two different maltodextrin types (DE 6 and DE 21) with different molecular weights as protective wall materials on the physical and polymorphic stability of the solid lipid particles. The results revealed that the low molecular weight maltodextrin DE 21 was a superior wall material in stabilizing the solid lipid particles. Moreover, the lipid particles spray dried at Tinlet/outlet of 140/65 °C exhibited the highest physical and polymorphic stability, whereas using higher Tinlet/outlet led to bigger particles which were more prone to polymorphic transition. This was also verified in a 71-day storage test. The findings were explained that by preventing the melting of the tristearin carrier lipid during spray drying, the crystallized lipid particles remained intact inside the amorphous maltodextrin layer and exhibited high physical and polymorphic stability. These findings are important for generating stable food-grade spray dried powders.


Assuntos
Dessecação/métodos , Ácidos Graxos Ômega-3/química , Óleos de Peixe/química , Lipídeos/química , Nanopartículas/química , Excipientes , Temperatura Alta , Lecitinas , Peso Molecular , Nanoestruturas , Polissacarídeos , Pós , Saponinas de Quilaia , Triglicerídeos
13.
Annu Rev Food Sci Technol ; 10: 43-73, 2019 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-30664381

RESUMO

Consumer concerns about synthetically derived food additives have increased current research efforts to find naturally occurring alternatives. This review focuses on a group of natural surfactants, the Quillaja saponins, that can be extracted from the Quillaja saponaria Molina tree. Quillaja saponins are triterpenoid saponins comprising a hydrophobic quillaic acid backbone and hydrophilic sugar moieties. Commercially available Quillaja saponin products and their composition and properties are described, and the technofunctionality of Quillaja saponins in a variety of food, cosmetic, and pharmaceutical product applications is discussed. These applications make use of the biological and interfacial activities of Quillaja saponins and their ability to form and stabilize colloidal structures such as emulsions, foams, crystallized lipid particles, heteroaggregates, and micelles. Further emphasis is given to the complexation and functional properties of Quillaja saponins with other cosurfactants to create mixed surfactant systems, an approach that has the potential to facilitate new interfacial structures and novel functionalities.


Assuntos
Saponinas de Quilaia/química , Quillaja/química , Saponinas de Quilaia/farmacologia , Reologia
14.
J Colloid Interface Sci ; 519: 71-80, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29482098

RESUMO

HYPOTHESIS: This study examined the emulsifying properties of mixed surfactant systems of Quillaja saponins and food-grade co-surfactants (Na-caseinate, pea protein, rapeseed lecithin, and egg lecithin). We hypothesized to these mixtures may build mixed adsorption layers and thus enhance emulsion stabilization. EXPERIMENTS: Oil-in-water emulsions (10%, pH 7) were prepared with different concentrations of co-surfactants (0.1-5.0%) alone or mixed with Quillaja saponins (0.05 or 0.5%). Dynamic interfacial tension measurements were performed to characterize the behavior of the surfactants at an oil-water interface. FINDINGS: Low Quillaja saponin concentrations led to either no changes or substantial increases in particle sizes of protein stabilized emulsions, but d43-values decreased in lecithin stabilized emulsions at low lecithin concentrations. The dominating effect of Quillaja saponins at high concentrations led to formation of small droplets (d43≤2 µm) in all emulsions, except with 2.5% pea proteins. All co-surfactants showed synergistic or additive effects with respect to interfacial tension reductions upon addition of Quillaja saponins (except for egg lecithin with 0.005% Quillaja saponin addition). The results indicated a competing effect for saponin-protein interfaces, but formation of mixed saponin-lecithin interfaces, thus showing that the emulsion stabilization and interfacial properties can be tuned by specific binary surfactant mixtures.

15.
J Agric Food Chem ; 65(20): 4153-4160, 2017 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-28453286

RESUMO

The interfacial and emulsion-forming properties of sugar beet extract (Beta vulgaris L.) were examined and compared to a Quillaja extract that is widely used within the food industry. We investigated the influence of extract concentration on surface activity at oil-water and air-water interfaces and on the formation of oil-in-water emulsions (10% w/w, pH 7). Sugar beet extract reduced the interfacial tension up to 38% at the oil-water interface, and the surface tension up to 33% at the air-water surface. The generated emulsions were negatively charged (ζ ≈ -46 mV) and had the smallest particle sizes (d43) of ∼1.3 µm at a low emulsifier-to-oil ratio of 0.75:10. Applying lower or higher extract concentrations increased the mean particle sizes. The smallest emulsions were formed at an optimum homogenization pressure of 69 MPa. Higher homogenization pressures led to increased particle sizes. Overall, sugar beet extract showed high surface activity. Furthermore, the formation of small emulsion droplets was successful; however, the droplets were bigger compared to those from the Quillaja extract. These results indicate sugar beet as an effective natural emulsifier that may be utilized for a variety of food and beverage applications.


Assuntos
Beta vulgaris/química , Extratos Vegetais/química , Emulsificantes/química , Emulsificantes/isolamento & purificação , Emulsões/química , Manipulação de Alimentos , Tamanho da Partícula , Extratos Vegetais/isolamento & purificação , Quillaja/química
16.
J Colloid Interface Sci ; 490: 207-216, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-27912119

RESUMO

HYPOTHESIS: This study demonstrates that tuning the shell thickness of lipid particles can modulate their oxidative stability. We hypothesized that a thick crystallized shell around the incorporated fish oil would improve the oxidative stability due to the reduced diffusion of prooxidants and oxygen. EXPERIMENTS: We prepared solid lipid nanoparticles (5%w/w lipid phase, 1.5%w/w surfactant, pH 7) by using different ratios of tristearin as carrier lipid and ω-3 fish oil as incorporated liquid lipid stabilized by high- or low-melting lecithin. The physical, polymorphic and oxidative stability of the lipid particles was assessed. FINDINGS: The high-melting lecithin was the key in inducing the formation of a solidified tristearin shell around the lipid particles by interfacial heterogeneous nucleation. Lipid particles containing a higher ratio of tristearin showed a better oxidative stability. The results revealed that a crystallized tristearin layer above 10nm was required to inhibit oxidation of the incorporated fish oil. This cut-off was shown for lipid particles containing 50-60% fish oil. This research gives important insights into understanding the relation between the thickness of the crystallized shell around the lipid particles and their chemical stability.


Assuntos
Emulsões/química , Excipientes/química , Ácidos Graxos Ômega-3/química , Óleos de Peixe/química , Lecitinas/química , Triglicerídeos/química , Cristalização , Nanopartículas/química , Oxirredução , Transição de Fase , Tensoativos/química
17.
Food Res Int ; 88(Pt A): 16-23, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28847396

RESUMO

Thermal treatment of mixed surfactant systems can have a major impact on their phase behavior through modified interactions between the surfactants. In this study, we investigated the miscibility behavior of aqueous binary surfactant systems composed of Quillaja saponin extract and sodium caseinate, pea protein, rapeseed lecithin, or egg lecithin at different concentration ratios (0-5% w/v) at pH3, 5, and 7 upon heat treatment (25-75°C). The results revealed that the heat-treated Quillaja saponin-sodium caseinate mixtures at pH7 remained miscible when the ratio of Quillaja saponins was equal or higher to the ratio of caseinate, otherwise the mixtures flocculated due to increased hydrophobic interactions. At pH3, the aggregation of Quillaja saponin-sodium caseinate structures was intensified by heating mainly through self-association of casein molecules. In Quillaja saponin-pea protein mixtures as well as in pure pea protein samples heating led to weakening of the gel structures at all tested pH values. In contrast, heating did not affect Quillaja saponin-rapeseed lecithin mixtures, which stayed miscible independent of pH due to electrostatic repulsive forces. Furthermore, the flocculated (pH5, 7) or aggregated (pH3) Quillaja saponin-egg lecithin mixtures were only slightly affected by heating. These results are important for understanding the interactions of binary surfactant systems when subjected to heating, which is a common processing step in many food applications.

18.
Food Chem ; 190: 928-937, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26213058

RESUMO

We investigated the influence of physicochemical properties of encapsulated functional lipids--vitamin A, ß-carotene and ω-3 fish oil--on the structural arrangement of solid lipid nanoparticles (SLN). The relationship between the crystal structure and chemical stability of the incorporated bioactive lipids was evaluated with different emulsifier compositions of a saponin-rich, food-grade Quillaja extract alone or combined with high-melting or low-melting lecithins. The major factors influencing the structural arrangement and chemical stability of functional lipids in solid lipid dispersions were their solubility in the aqueous phase and their crystallization temperature in relation to that of the carrier lipid. The results showed that the stabilization of the α-subcell crystals in the lattice of the carrier lipid is a key parameter for forming stable solid lipid dispersions. This study contributes to a better understanding of SLN as a function of the bioactive lipid.


Assuntos
Sistemas de Liberação de Medicamentos , Lipídeos/química , Nanopartículas/química , Antioxidantes/farmacologia , Cristalização , Estabilidade de Medicamentos , Ácidos Graxos Ômega-3/química , Lecitinas/administração & dosagem , Transição de Fase , Extratos Vegetais/administração & dosagem , Quillaja , Tensoativos/farmacologia , Vitamina A/química , beta Caroteno/química
19.
J Food Sci ; 80(11): E2495-503, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26458074

RESUMO

The miscibility behavior of mixed surfactant systems and the influence of extrinsic parameters are crucial for their application as emulsifiers. Therefore, the objective of this study was to evaluate the miscibility behavior of mixed systems composed of commercial Quillaja saponin and a co-surfactant, namely sodium caseinate, pea protein, rapeseed lecithin, or egg lecithin. These mixtures were evaluated macro- and microscopically at different concentration ratios (maximum concentration 5% w/v) at pH 3, 5, and 7 at 25 °C. The individual ingredients were also assessed for their charge properties and surface hydrophobicity. The results showed that Quillaja saponin-caseinate mixtures were miscible only at pH 7, and showed aggregation and precipitation at lower pH due to increasing electrostatic attraction forces. Rheological measurements showed that Quillaja saponin-pea protein mixtures formed gelled structures at all tested pH values mainly via association of hydrophobic patches. Quillaja saponins mixed with rapeseed lecithin were miscible at all tested pH values due to electrostatic repulsion. Quillaja saponin-egg lecithin mixtures aggregated independent of pH and concentration ratio. The microscopic analysis revealed that the lower the pH and the higher the Quillaja saponin ratio, the denser were the formed Quillaja saponin-egg lecithin aggregates. The results are summarized in ternary phase diagrams that provide a useful tool in selecting a surfactant system for food applications.


Assuntos
Emulsificantes/química , Saponinas de Quilaia/química , Quillaja/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Reologia , Eletricidade Estática , Tensoativos/química
20.
J Colloid Interface Sci ; 448: 114-22, 2015 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-25723787

RESUMO

HYPOTHESIS: This study investigated the influence of liquid-solid transition and particle size on the optical properties of nanoemulsions. The hypothesis was that the crystallization of lipid droplets influences the nanoemulsion appearance. EXPERIMENTS: Liquid and solid nanoemulsions (10 wt% octadecane, 1-5 wt% sodium dodecylsulfate) were formed by high-pressure microfluidization (5000-28,500 psi) at 45 °C. Solid lipid nanoparticles were formed by cooling the nanoemulsions to 5 °C and then heating to ambient temperature, whereas liquid nanoemulsions were formed by maintaining them at 25 °C. FINDINGS: Results indicated that lipid nanoparticles ranging from 136 nm down to 36 nm were generated, and were stable to particle aggregation. The melting and onset temperatures of the nanoparticles decreased with decreasing particle diameter. Upon crystallization of the lipid, the absorbance increased by about 140% for nanoemulsions with 136 nm particle diameter, but only 5% for nanoemulsions with 36 nm particle diameter. These results were explained in terms of changes in refractive index upon droplet solidification that alter their scattering behavior. These results show that solidification of nanoemulsions results in a shift of the transparent-to-turbid transition regime. The practical consequences for emulsion manufacturers are that solid nanoemulsions must be smaller than liquid nanoemulsions to remain transparent.


Assuntos
Emulsões/química , Lipídeos/química , Nanopartículas/química , Alcanos/química , Cristalização , Luz , Tamanho da Partícula , Transição de Fase , Dodecilsulfato de Sódio/química , Espectrofotometria Ultravioleta
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