Preparation and characterization of carnauba wax nanostructured lipid carriers containing benzophenone-3

Nanostructured lipid carriers (NLCs) are potential active delivery systems based on mixtures of solid lipids and liquid oil. In this paper, aqueous dispersions of NLCs were prepared by a hot high-pressure homogenization technique using carnauba wax as the solid lipid and isodecyl oleate as the liquid oil. The preparation and stability parameters of benzophenone-3-loaded NLCs have been investigated concerning particle size, zeta potential and loading capacity to encapsulate benzophenone-3, a molecular sunscreen. The current investigation illustrates the effect of the composition of the lipid mixture on the entrapment efficiency, in vitro release and stability of benzophenone-3-loaded in these NLCs. A loading capacity of approximately 5% of benzophenone-3 (m(BZ-3) /m(lipids) ) was characteristic of these systems.     

Beta-carotene-loaded nanostructured lipid carriers

ABSTRACT:  Nanostructured lipid carriers (NLC) technology was used to disperse hydrophobic β-carotene in an aqueous phase. NLC are lipid nanoparticles with a particle matrix consisting of a blend of a liquid and solid lipid. They were produced by melting the lipid blend at 80 °C and dispersing it into a hot emulsifier solution. The aim of this study was to extend the limited knowledge of melt-emulsified lipidic colloids in food systems and to evaluate the feasibility for further applications as functional ingredient in beverages. Physical stability of the NLC suspension was examined at 2 different storage temperatures by measuring the particle size with photon correlation spectroscopy (PCS) and laser diffractometry (LD). All particles containing sufficient amounts of emulsifier were smaller than 1 μm (LD diameter 100%) at a mean particle size of around 0.3 μm (LD) for 9 wk at 20 °C and at least 30 wk at 4 to 8 ° C. Differential scanning calorimetry (DSC) was used to study the solid state of the lipids both in the β-carotene loaded PGMS and in the NLC particles. Propylene glycol monostearate (PGMS) when dispersed as NLC recrystallized up to 98% during storage time. Within the regarded period of 7 mo no polymorph transitions were observed. Furthermore, stability of the β-carotene in water dependent on NLC concentration and tocopherol content was measured photospectrometrically to get an estimation of the behavior of NLC in beverages.     

Dispersions of lamellar phases of non-ionic lipids in cosmetic products

Although aqueous dispersions of lipids in the form of particles having a lamellar structure (liposomes) are already known as excellent vehicles for pharmaceutical substances, their usefulness in cosmetic formulations has not been demonstrated. The present work shows the advantages obtained by application of such systems to the skin, and in particular the use of non-ionic lipids in aqueous dispersions. Thus, in comparison with classical formulations such as emulsions, these systems exhibit lower toxicity and permit closer control of the availability of active substances at the stratum corneum. As examples, compositions suitable for skin moisturising and for tanning products are presented. Dispersions de phases lamellaires de lipides non-ioniques en cosmétique     

Dispersion of bioactive substances in oils by supercritical antisolvent technology (BIOSAS process)

This work presents the novel method named BIOSAS to formulate homogenous dispersions of bioactive substances in an oily matrix. The method is based on the carbon dioxide supercritical antisolvent (SAS) technique to produce small drops of a solution containing the bioactive substances, in the presence of a lipid substance. Ethanolic and aqueous solutions were used to solubilize complex mixtures of phytochemicals depending on the polarity of compounds. Ethanol was removed entirely from the droplets by SAS effect, and solid bioactive particles with mean diameters below 1 μm were uniformly dispersed in the lipid matrix; for aqueous solutions, the water droplets produced were high-pressure mixed with the lipid phase containing an emulsifier, and stable emulsions were obtained. BIOSAS permits particle size control and can be used to formulate lipid-based nutraceuticals or food supplements in an inert atmosphere and at low temperatures, contributing to reducing the oxidation and thermal degradation of bioactive substances and lipid matrix.     

Solid Lipid Dispersions: Potential Delivery System for Functional Ingredients in Foods

Structured solid lipid (SL) systems have the advantages of long‐term physical stability, low surfactant concentrations, and may exhibit controlled release of active ingredients. In this research work, the potential use of high‐melting SLs for the production of the above structured SL carrier systems was investigated. Dispersions containing either SL or blend of solid lipid and oil (SL+O) were produced by a hot melt high‐pressure homogenization method. Experiments involved the use of 3 different SLs for the disperse phase: stearic acid, candelilla wax and carnauba wax. Sunflower oil was incorporated in the disperse phase for the production of the dispersions containing lipid and oil. In order to evaluate the practical aspects of structured particles, analytical techniques were used including: static light scattering to measure particle sizes, transmission electron microscopy (TEM) for investigating particle morphology and differential scanning calorimetry (DSC) to investigate the crystallization behavior of lipids in bulk and in dispersions. Results showed different mean particle sizes depending on the type of lipid used in the disperse phase. Particle sizes for the 3 lipids were: stearic acid (SL: 195 ± 2.5 nm; SL+O: 138 ± 6.0 nm); candelilla wax (SL: 178 ± 1.7 nm; SL+O: 144 ± 0.6 nm); carnauba wax (SL: 303 ± 1.5 nm; SL+O: 295 ± 5.0 nm). TEM results gave an insight into the practical morphology, showing plate‐like and needle‐like structures. DSC investigations also revealed that SL dispersions melted and crystallized at lower temperatures than the bulk. This decrease can be explained by the small particle sizes of the dispersion, the high‐specific surface area, and the presence of a surfactant.     

Nanostructured lipid carriers as novel carrier for sunscreen formulations

Incorporation of sunscreens into lipid carriers with an increased sun protection factor (SPF) has not yet been fully accomplished. In the present paper, the effectiveness of a sunscreen mixture, incorporated into the novel topical delivery systems, i.e. solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), used as ultraviolet (UV) protector enhancers with a distinctly higher loading capacity has been developed and evaluated. SLN and NLC were produced by hot high pressure homogenization technique in lab scale production. Size distribution and storage stability of formulations were investigated by laser diffractometry and photon correlation spectroscopy. Nanoparticles were characterized by their melting and recrystallization behaviour recorded by differential scanning calorimetry. Lipid nanoparticles produced with a solid matrix (SLN and NLC) were established as a UV protection system. The loading capacities for molecular sunscreens reported before now were in the range of 10-15%. It was possible to load NLC with up to 70% with molecular sunscreen, which is appropriate to obtain high SPFs with this novel UV protection system. The developed formulations provide a beneficial alternative to conventional sunscreen formulations. The UV protective efficacy of the lipid particles varied with the nature of lipid and UV wavelength.     

Development and characterisation of a novel krill oil nanostructured lipid carrier based on 1,3-glycerol distearate

A novel nanostructured lipid carrier (NLC) loaded with Antarctic krill oil while using 1,3-glycerol distearate (GDS) as the solid lipid was prepared through ultrasonication. The NLCs were optimised for ingredient formulation by single-factor experiment on the basis of their effects on the particle size and polydispersity index (PDI) of the NLCs. 2% (w/w) lecithin and 10% lipid phase of which krill oil accounted for 50% (w/w) were applied to develop the optimised NLC dispersion. The particle size, PDI and zeta potential of this NLC were 112 nm, 0.270 and −30.8 mV, respectively, indicating good dispersion uniformity and stability. Transmission electron microscopy (TEM) revealed that the optimised NLC particles were spherical and uniformly dispersed without apparent aggregation. Differential calorimetry scanning (DSC) and X-ray diffraction (XRD) showed that the optimised NLC had less-ordered crystalline structure contributing to the high entrapment efficiency (> 99%) of EPA and DHA.     

Control of Morphological and Rheological Properties of Carrot Cell Wall Particle Dispersions through Processing

A range of thermal and mechanical processes were used to create dispersions with different particle morphologies, i.e., systems that contain primarily plant cell wall clusters with an average particle size (d(0.5)) of ～200 µm, single cells ((d(0.5)?=?～70 µm) or cell fragments (d(0.5)?=?～40 µm). The small and large deformation rheology (viscoelastic properties and flow properties) of these dispersions, with a range of total solid contents covering textures varying from a fluid to a paste, were determined. The particle dispersions showed weak gel-like behaviour. Their elastic modulus (G′) as a function of total solid content exhibited three regions of different rheological behaviours. The particles formed particulate colloidal networks at relatively low solid content. The interaction of particles contributed to the sharp increase in the elastic modulus of the dispersion in the concentrated region. Further packing of particles beyond the critical packing volume fraction, caused the G′ for the ‘cluster-cell’ and the ‘single-cell’ dispersions to reach a plateau value. This is due to particle deformation resulting in changes in their microstructure and their ability to pack closely. Plant particle dispersions displayed abrupt yielding at the critical stress with a 3–4 order decrease in viscosity and high yield stress at low solids due to the formation of particulate colloidal network.     

Abstracts: The properties and application of a novel amphiphilic polymer as an active interfacial modifier

pp.247–253 A peptide/silicone hybrid functional polymer composed of silk peptide and silicone resin with a hydrophobic alkyl group was investigated for its compatibility and functionality as a cosmetic ingredient. We have found this polymer provides characteristic functions to modify and control various interfacial properties and named it active interfacial modifier (AIM‐FN). At the liquid/liquid interface, AIM‐FN worked as an excellent W/O emulsifier for various oils, polar or non‐polar, and even for silicone oil. In principle AIM‐FN stays at the interface between the aqueous phase and lipid phase because it is not compatible with either phase. At liquid/solid interfaces, the peptide moiety of AIM‐FN attaches to the hydrophilic solid surface and makes it water repellant and water proof with its hydrophobic silicone and alkyl residue. An emulsion formulated with AIM‐FN gives a non‐oily and non‐tacky skin feeling as AIM‐FN improves the solid/solid (skin/skin) surface property.     

Influence of different solid lipids on the properties of a novel nanostructured lipid carrier containing Antarctic krill oil

This study aimed to investigate the effect of solid lipids (lauric acid (LAU), myristic acid (MYR), stearic acid (STE), glycerol monostearate (GMS), glycerol 1,3-distearate (GDS), glycerol tristearate (GTS), glycerol trimyristate (GTM) and glycerol trilaurate (GTL)) on the characteristics of novel nanostructured lipid carrier (NLC) containing Antarctic krill oil through ultrasound. The fatty acids (LAU, MYR, STE and GMS) were unsuitable solid lipid materials, as apparent stratification was quickly observed during the NLC preparation. NLCs were successfully prepared using GTS, GTM, GTL and GDS. The zeta potential of all NLCs exceeded −30 mV indicating good uniformity and stability. These NLCs appeared spherical or oval. Differential calorimetry and X-ray diffraction analysis revealed these NLCs formed imperfect crystals. As the carbon chain length of triglycerides increased from C₁₂ to C₁₈, the particle size of NLCs increased from 235.8 ± 2.3 nm to 340.5 ± 2.2 nm, the degree of recrystallisation increased from 39.06% to 49.99%, while the EPA encapsulation efficiency decreased from 88.72 ± 0.47% to 72.86 ± 1.06%. NLC prepared with GDS had the smallest particle size (112.4 ± 0.4 nm), the lowest recrystallisation and the highest EPA encapsulation efficiency (>99%). GDS was the most suitable to prepare high encapsulate efficiency krill oil-loaded NLC.     

植物甾醇和核桃油复配的纳米结构脂质载体的制备及其稳定性研究

本研究通过高压均质法采用核桃油为液体脂质制备用于封装、保护植物甾醇(Phytosterol,PS)的纳米结构脂质载体(Nanostructured lipid carriers,NLC)。以平均粒径、多分散指数、Zeta电位及包封率等为主要评价指标,对制备工艺参数及配方进行优化,同时对优化后的PS-NLC进行形貌观察及稳定性研究。通过正交试验确定制备PS-NLC的最佳比例为总脂质浓度10%,硬脂酸和核桃油的比例为2:3,大豆卵磷脂浓度为1.2%。制备得到的PS-NLC外观呈球形,粒径较小且分布均匀。PS-NLC的稳定性结果表明:PS-NLC在4℃下储藏28 d稳定性良好;在使用时可以在5～100倍之间进行稀释,具有良好的稀释稳定性;添加2%的蔗糖对PS-NLC的冻干保护效果最佳。本文利用核桃油作为NLC的壁材为植物甾醇提供了一个合适的脂质运载系统,可为食品工业构建PS-NLC提供技术支持。     

Skin lipids

Concepts regarding the structure and function of the stratum corneum (SC) have changed from that of a tough film of loosely adherent cells to that of a two-compartment system of protein-enriched cells embedded in intercellular lipids. The two-compartment arrangement enlarged the role of epidermal lipids from that of the plasticizing component of the SC to that of the epidermal barrier governing water-holding properties as well as take-up of water, the differences in permeability of topically applied lipophilic and hydrophilic agents as well as cohesion and desquamation of the SC. Barrier properties of SC are dependent largely on the intactness of the lipid lamellae that surround the corneocytes. The pliability of the SC depends on a correct balance of lipids, hygroscopic water-soluble substances and water.
Mammalian differentiation involves characteristic changes in lipid composition consistent with the requirements for waterproofing. There is a progressive depletion of phospholipids and glycosphingolipids with enrichment in ceramides, cholesterol, free fatty acids, and small amounts of other polar (e.g. cholesterol sulphate) and non-polar species (e.g. hydrocarbons, cholesterol esters, triglycerides). The sphingolipids account for the most lipid by weight and are presumed to be of major importance for the water-retaining properties of the epidermal barrier. Decrease of sphingolipid content occurs in aged skin. Deficiency of essential fatty acids leads to enhanced transdermal water transport in addition to dryness and scaliness of the skin. A mixture of both saturated and unsaturated fatty acids produces the optimal barrier to water loss from the SC. The balance between solid crystal and liquid crystalline phases in epidermal lipids is determined by the degree of fatty acid unsaturation and the amount of water.     

Influence of tragacanth gum exudates from specie of Astragalus gossypinus on rheological and physical properties of whey protein isolate stabilised emulsions

The aim of this work was to investigate the effects of Iranian tragacanth gum (Astragalus gossypinus) (0.5, 1 wt.%), Whey protein isolate (WPI) (2, 4 wt.%) and acid oleic‐phase volume fraction (5, 10% v/v) on droplet size distribution, creaming index and rheological properties of emulsions with various compositions. Rheological investigations showed that both loss and storage modules increased with gum and oil contents. However, the viscoelastic behaviour was mainly governed by the gum concentration. Delta degree (storage and loss modules ratio) increased with frequency indicated that liquid like viscose behaviour dominates over solid like elastic behaviour. The shear‐thinning behaviour of all dispersions was successfully modelled with power law and Ellis models and Ellis model was founded as the better model to describe the flow behaviour of dispersions. Droplet size distribution was measured by light scattering; microscopic observations revealed a flocculated system. Increase in gum, WPI and oil contents resulted in decrease in creaming index of emulsions with dominant effect of gum concentration.     

Structuring of lipid phases using controlled heteroaggregation of protein microspheres in water-in-oil emulsions

The effect of heteroaggregation of oppositely charged protein microspheres dispersed within a liquid oil phase on the microstructure and rheological properties of water-in-oil (W/O) emulsions was evaluated. The aqueous phase of the initial W/O emulsions contained either 10% β-lactoglobulin or 10% lactoferrin (pH 7, 100 mM NaCl). At this pH, β-lactoglobulin (BLG) is negatively charged while lactoferrin (LF) is positively charged. The oil phase consisted of a lipophilic non-ionic surfactant (8% polyglycerol polyricinoleate, PGPR) dispersed within soybean oil. Three 40% W/O emulsions were formed containing different types of protein microspheres: (i) BLG: 100% BLG droplets; (ii) LF: 100% LF droplets; and (iii) Mixed: 50% BLG droplets and 50% LF droplets. Prior to heating, the mixed emulsions had a higher shear viscosity, yield stress, and shear modulus than the BLG or LF emulsions, which suggested that electrostatic attraction led to the formation of a three-dimensional network of aggregated droplets. All three W/O emulsions underwent an irreversible fluid-to-solid transition when they were heated above ≈70 °C. This phenomenon was attributed to thermal denaturation of the globular BLG and LF molecules within the aqueous phase promoting aggregation and network formation of the protein microspheres. After heating, the mixed emulsions had a higher shear viscosity, yield stress and shear modulus than the BLG or LF emulsions, suggesting that a stronger droplet network was formed due to electrostatic attraction. Shear rheology measurements of the W/O emulsions showed that the lipid phases formed after heating were non-ideal plastics characterized by a yield stress and shear thinning behavior. These results may facilitate the design of semi-solid or solid foods with reduced saturated- or trans-fat contents suitable for use in commercial products.     

基于微胶囊技术对油脂包埋的研究进展

油脂来源广泛、营养丰富,在医药、食品及化妆品等领域中具有很高的应用价值,但因含有不饱和脂肪酸而易被氧化变质,使其应用受到一定的限制。微胶囊技术是一项具有很高实用价值并被广泛应用的新技术。采用微胶囊化技术可将油脂包埋形成微胶囊,一方面可以将油脂与空气隔离,防止被氧化,同时可以掩蔽不良风味;另一方面,油脂的微胶囊化可以改善油脂的多方面性质,使其转化成固体粉末,并使其获得更多的特殊功能,拓宽油脂的应用范围。本文将主要围绕微胶囊的结构组成、微胶囊的制备方法、微胶囊释放机制、油脂微胶囊化的优势及微胶囊化技术在各类油脂中的应用现状进行综述,为油脂微胶囊化研究提供一些理论依据,为油脂产品或其他生物活性物质进一步的使用和开发提供借鉴。     

Digestibility and β-carotene release from lipid nanodispersions depend on dispersed phase crystallinity and interfacial properties

The influence of interfacial structure and lipid physical state on colloidal stability and digestibility of solid lipid nanoparticle dispersions (SLN) and canola oil-in-water emulsions (COE) stabilized with the non-ionic surfactants Poloxamer 188 (P188) and Tween 20 (T20) were examined and the release of encapsulated β-carotene (BC) under simulated gastrointestinal conditions determined. While the SLN and COE were all stable during exposure to gastric conditions (mean diameter ～115 nm), more destabilization was observed for the COE than SLN during the duodenal phase. ζ-Potential measurements indicated rapid adsorption of bile salts (BS) and phospholipids (PL) to both solid and liquid interfaces, with greater surfactant displacement observed for the COE. Compared to the SLN, significantly more lipolysis and BC transfer to the aqueous phase was observed for both the COE-P188 and COE-T20 (p < 0.05). The properties of the colloidal structures present in the aqueous phase, which are important in terms of the uptake of lipolytic products and lipophilic bioactives, depended on non-ionic surfactant type, the extent of lipid digestion, as well as the presence of BS and PL.     

Cosmetic features and applications of lipid nanoparticles (SLN, NLC)

A detailed review of the literature is presented in attempts to emphasize several advantages of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) for cosmetic applications. Examples of several actives are given and the main features of the solid core of SLN and NLC for topical delivery of cosmetics are discussed. Lipid nanoparticles have been more and more explored in pharmaceutical technology, showing superior advantages for topical purposes over conventional colloidal carriers.     

Membrane Structured Solid Nanoparticles – A Novel Nanotechnology for Delivery of Cosmetic Active Ingredients

Lipid nanoparticles have a structure similar to that of nanoemulsions. Their size ranges typically from 50 to 1000 nm. They differ from nanoemulsions in that the lipid core is a solid. The matrix consists of solid lipids or mixtures of lipids. Over the past years it has been demonstrated that solid lipid nanoparticles appear to be a promising drug carrier system for the future. Their occlusion properties reduce transepidermal water loss and can enhance penetration of active ingredients through the stratum corneum. As with all new technologies, some problems with the solid lipid nanoparticle technology need to be solved. One major problem is the homogeneous incorporation of amphiphilic active ingredients into the crystal matrix of the nanoparticles. Actives with an amphiphilic character like tocopherol or retinol cannot be kept homogeneously distributed in the wax structure during the emulsification process. Due to their hydrophilic head group they accumulate at the exterior layer of the nanoparticles together with the surfactant system used. Consequently, homogeneous release over time is not guaranteed and a burst release has to be expected. A second disadvantage is the manufacturing process. Solid lipid nanoparticles can be produced only under high pressure conditions. Also the concentration of the solid particles in the dispersion, which is added to an emulsion, is quite low. To overcome these problems membrane structured solid nanoparticles (MSSN) have been developed. These MSSN systems consist of liquid crystalline membrane systems with extremely low surfactant concentrations. The lateral movement of actives is controlled by amphiphilic solid actives such as ceramides and solid emollients. This guarantees maintenance of the advantageous properties of solid lipid nanoparticles such as retarded release of actives and their protection against chemical decomposition, but it also allows the homogeneous incorporation of amphiphilic actives. Membrane structured solid nanoparticles are produced using a continuous three‐phase emulsification technique. This allows protection of heat‐sensitive actives against decomposition. The concentration of nanoparticles in the MSSN dispersion can be kept higher than 60% (w/w). Even at these concentrations the nanodispersions keep their flow properties. As a result, they can be easily incorporated into the final formulation.     

Rheological and Microstructural Properties of Porcine Myofibrillar Protein–Lipid Emulsion Composite Gels

ABSTRACT:  The objective of the study was to investigate the role of emulsified fat (lard) and oil (peanut oil) in the rheology and microstructure of porcine myofibrillar protein (MP) gels. Heat-induced composite gels were prepared from 2% MP with 0% to 15% pre-emulsified lipids at 0.6 M NaCl, pH 6.2. Dynamic rheological testing upon temperature sweeping (20 to 80 °C at 2 °C/min) showed substantial increases in G ' (an elastic modulus) of MP sols/gels with the addition of emulsions. Gel hardness was markedly enhanced ( P < 0.05) by incorporating ≥10% emulsions, and the composite gel with 15% lard was 33% more rigid ( P < 0.05) than that with 15% peanut oil. Incorporation of both emulsions at 10% or higher levels improved the water holding capacity of the gels by 28% to 44% ( P < 0.05). Light microscopy revealed a compact gel structure filled with protein-coated fat/oil globules that interacted with the protein matrix via disulfide bonds. The results indicated that both physical and chemical forces contributed to the enhancements in the rheology, moisture retention, and lipid stabilization in the MP–emulsion composite gels.