Applications and perspectives of polyphenol-loaded solid lipid nanoparticles and nanostructured lipid carriers for foods

Food Science and Biotechnology - Imbalanced nutrition in modern society is one of the reasons for disorders, such as cancer, cardiovascular disease, and diabetes, which have attracted the interest...     

水飞蓟素固体脂质纳米粒的制备

目的　研制水飞蓟素固体脂质纳米粒。方法　以硬脂酸为载体采用溶剂乳化法制备水飞蓟素固体脂质纳米粒,并用葡聚糖凝胶层析法测定其包封率。结果　所得含药固体脂质纳米粒水分散体为稳定的乳白色混悬液,对药物的包封率为2 8.0 2 %。结论　溶剂乳化法适用于水飞蓟素固体脂质纳米粒的制备。     

Encapsulation of emulsified tuna oil in two-layered interfacial membranes prepared using electrostatic layer-by-layer deposition

Tuna oil-in-water emulsions (5 wt% tuna oil, 100 mM acetate buffer, pH 3.0) containing droplets stabilized either by lecithin membranes (primary emulsions) or by lecithin–chitosan membranes (secondary emulsions) were produced. The secondary emulsions were prepared using a layer-by-layer electrostatic deposition method that involved adsorbing cationic chitosan onto the surface of anionic lecithin-stabilized droplets. Primary and secondary emulsions were prepared in the absence and presence of corn syrup solids (a carbohydrate widely used in the micro-encapsulation of oils) and then their stability to environmental stresses was monitored. The secondary emulsions had better stability to droplet aggregation than primary emulsions exposed to thermal processing (30–90 °C for 30 min), freeze-thaw cycling (−18 °C for 22 h/30 °C for 2 h), high sodium chloride contents (200 mM NaCl) and freeze-drying. The addition of corn syrup solids decreased the stability of primary emulsions, but increased the stability of secondary emulsions. The interfacial engineering technology used in this study could lead to the creation of food emulsions with novel properties or improved stability to environmental stresses.     

Formation of biopolymer-coated liposomes by electrostatic deposition of chitosan

ABSTRACT:  The purpose of this study was to prepare stable biopolymer-coated liposome suspensions using an electrostatic deposition method. Liposome suspensions were produced by homogenizing 1% soy lecithin in acetate buffer (0.1 M, pH 3). Cationic chitosan (Mw approximately 200 kDa) solutions were mixed with anionic liposome suspensions ( d approximately 100 and 200 nm), and the effect of phospholipid concentration, chitosan concentration, and liposome size on the properties of the particles formed was determined. The particle size and charge (ζ-potential) were measured using dynamic light scattering and particle electrophoresis. The particle charge changed from –38 mV in the absence of chitosan to +60 mV in the presence of chitosan, indicating complex formation between the anionic liposomes and cationic chitosan molecules. Below a minimum critical chitosan concentration ( c _min), large aggregates were formed that phase separated within minutes, whose origin was attributed to formation of coacervates. On the other hand, above a maximum critical chitosan concentration ( c _max), large flocs were formed that sedimented within hours, whose formation was attributed to depletion flocculation. Minimum and maximum critical chitosan concentrations depended on liposomal concentration and size. At c _min < c < c _max, chitosan-coated liposomes were formed that did not aggregate and were stable to sedimentation. Coated liposomes had better stability to aggregation than uncoated liposomes when stored at ambient temperatures for 45 d. This study indicates that chitosan can be used to form biopolymer-coated liposomes with enhanced stability over uncoated liposomes.     

Characterization of spray-dried tuna oil emulsified in two-layered interfacial membranes prepared using electrostatic layer-by-layer deposition

Tuna oil-in-water emulsions containing droplets stabilized by lecithin–chitosan membranes were produced using an electrostatic layer-by-layer deposition process. Corn syrup solids were added to the emulsions and then the emulsions were spray-dried, which produced a powder consisting of spheroid microcapsules (diameter = 5–30 μm) containing tuna oil droplets (diameter <1 μm) embedded within a carbohydrate wall matrix. The powders had relatively low moisture contents (<3%), high oil retention levels (>85%) and rapid water dispersibility (<1 min). The structure of the microcapsules was unaffected by drying temperature from 165 to 195 °C. We have demonstrated that a novel interfacial engineering technology, based on production of multilayer membranes around oil droplets, is effective for producing spray-dried encapsulated tuna oil. The powdered tuna oil produced by this method has good physicochemical properties and dispersibility, which may lead to its more widespread utilization as a food additive.     

Characterization of ergocalciferol loaded solid lipid nanoparticles

Abstract: The use of solid lipid nanoparticles (SLNs) is a technique that has been widely used in the pharmaceutical industry for the last 2 decades and has become of increasing interest to food scientists due to its potential for encapsulation and controlled release. Ergocalciferol (vitamin D₂) is a bioactive compound whose deficiency may lead to rickets in children and osteomalacia in adults. In this study, ergocalciferol was encapsulated in tripalmitin SLNs stabilized by polysorbate 20 (Tween 20). SLN dispersions (5% w/w) were prepared by hot homogenization technique using a nozzle‐type high‐pressure homogenizer. Ergocalciferol at 0%, 5%, 10%, 15%, and 20% (w/w of lipid) was dissolved in the molten lipid at 80 °C, mixed with a 5% (w/w) aqueous solution of polysorbate 20 and homogenized at 138 MPa at 80 °C. Particle size, thermal properties, and microstructure were evaluated by dynamic light scattering (DLS), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) respectively. As the proportion of ergocalciferol in the SLN increased from 0% to 20%, the Z‐average values of the particles gradually decreased (P≤ 0.05) from approximately 120 nm to approximately 65 nm. DSC analysis of freeze dried SLN samples showed gradual decrease in enthalpies of fusion and crystallization for stable β‐subcell whereas for SLN dispersions, the enthalpy of fusion of unstable α‐subcell crystal increased with increased ergocalciferol loading. The TEM images of the ergocalciferol loaded SLN samples showed the presence of spherical as well as rod‐shaped nanoparticles. It was also observed that the turbidity of the SLN dispersions reduced noticeably with increased ergocalciferol loading. This finding could be useful in terms of fortification of clear juices with ergocalciferol. Practical Application: Solid lipid nanoparticles (SLNs) were used in this study to encapsulate vitamin D₂, a vitamin important for bone health. It was found that as the concentration of vitamin D₂ increased in the lipid phase of SLN dispersion, the clarity of the dispersion increased. Also, with increased vitamin D₂ concentration, the stability of lipid crystal structure was affected in a way that indicates higher capacity of lipid to incorporate the vitamin molecules and hence to protect them better from oxygen and light. This vitamin loaded SLNs may offer alternatives to milk and margarine as a source of vitamin D.     

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.     

过氧化氢酶固体脂质纳米粒制备和鉴定

利用双乳化和溶剂蒸发技术制备过氧化氢酶固体脂质纳米粒(CAT-SLN),通过单因素试验和响应面分析,确定最佳合成工艺条件为:将浓度为20 mg/mL酶溶液(内水相)加入至含TG和PC(PC:TG=15.24%)的二氯甲烷/丙酮(1/1)(油相),油相:内水相=5,超声作用20s乳化形成W/O乳状液;再加入1.5% Poloxmer188水溶液(第二相)中,W/O乳状液:第二相=1:4,超声作用30s乳化形成W/O/W型乳状液。所制备CAT-SLN为球型,没粘连,粒径大小较一致,平均粒径为274 nm,Z电位为-37.1 mV,多分散系数为0.273,包封率为74.51%。     

响应面法优化高压均质制备DHA固体脂质纳米粒

采用固体脂质纳米粒保护容易氧化的二十二碳六烯酸(DHA).以单硬脂酸甘油酯为壁材,DHA藻油为芯材,采用高压均质制备DHA固体脂质纳米粒(DHA-SLN).以DHA-SLN的包封率为指标,通过单因素实验和响应面法优化工艺参数,得出高压均质法制备DHA-SLN的最佳工艺条件是:芯壁比1∶65,均质压力80 MPa,乳化剂质量分数2.14％(占水相),均质8次.在此条件下,实验验证的DHA-SLN的包封率为74.45％.     

Formation of metallic copper nanoparticles at the soil-root interface

Copper is an essential element in the cellular electron-transport chain, but as a free ion it can catalyze production of damaging radicals. Thus, all life forms attempt to prevent copper toxicity. Plants diminish excess copper in two structural regions: rare hyperaccumulators bind cationic copper to organic ligands in subaerial tissues, whereas widespread metal-tolerant plants segregate copper dominantly in roots by mechanisms thought to be analogous. Here we show using synchrotron microanalyses that common wetlands plants Phragmites australis and Iris pseudoacorus can transform copper into metallic nanoparticles in and near roots with evidence of assistance by endomycorrhizal fungi when grown in contaminated soil in the natural environment. Biomolecular responses to oxidative stress, similar to reactions used to abiotically synthesize Cu0 nanostructures of controlled size and shape, likely cause the transformation. This newly identified mode of copper biomineralization by plant roots under copper stress may be common in oxygenated environments.     

Formation and stability of multiple-layered liposomes by layer-by-layer electrostatic deposition of biopolymers

The sequential deposition of biopolymers onto the surface of liposomes; lamellar bilayer vesicles composed of polar lipids; was investigated. Submicron-sized liposomes were prepared from lecithin with a high speed blender and an ultrasonic homogenizer. Positively (chitosan), and negatively (high methoxyl pectin and λ-carrageenan) charged biopolymers were alternatingly added to liposomes to build up to 6 sequentially-stacked interfacial layers on top of the phospholipid membranes. After formulation, particle size and ζ-potential of liposomes were determined using dynamic light scattering. The primary liposomes had diameters of approximately 80 nm. Particle size increased linearly with each successive deposition up to four layers but increased to several micrometers when a fifth and sixth layer was deposited indicating that aggregation may have occurred. Addition of λ-carrageenan as an anionic biopolymer led to less aggregation than when high methoxyl pectin was used. Results were attributed to (i) unbound polymers in the aqueous phase forming coacervates that may lead to depletion flocculation and (ii) unoccupied binding sites and uneven charge distributions causing bridging flocculation. Our results show the limitations of the layer-by-layer deposition approach, which is important for food manufacturers wishing to form very thick polymer layers to stabilize dispersions such as emulsions or liposomes.     

Development and evaluation of lipid nanocarriers for quercetin delivery: A comparative study of solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), and lipid nanoemulsions (LNE)

To understand the effect of the physical state and composition of the lipid materials on the formation and performance of lipid nanocarriers, three types of carriers namely, solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and lipid nanoemulsions (LNE) were prepared and compared. Quercetin was used as a model nutraceutical compound to evaluate the potency of these nanocarriers to increase bioaccessibility. Among the developed nanocarriers, quercetin loaded and free NLC showed the smallest particle size (∼34 and 47 nm) compared to SLN (∼103 and 127 nm) and LNE (∼82 and 83 nm). Encapsulation efficiency of quercetin in these nanocarriers was >90%. Stability of these nanocarriers in simulated stomach conditions was proved by their unaffected size and size distribution after incubation in simulated gastric fluid. Maximum bioaccessibility was observed with NLC and LNE (∼60%) compared to SLN (∼35%) and free quercetin solution (∼7%). Controlled release was observed in enzyme free simulated intestinal fluid with maximum release being obtained with LNE compared to SLN and NLC. This study showed that by optimally controlling the lipid physical state and composition, it is possible to fabricate the lipid nanocarriers with desired properties.     

构树黄酮固体脂质纳米粒的制备

黄酮类化合物具有显著的清除体内自由基、抗氧化、抗衰老等作用。以硬脂酸、卵磷脂为载体,采用乳化蒸发-低温固化法制备构树黄酮固体脂质纳米粒（SLN）。结果表明,采用PEG400作助乳化剂和稳定剂,硬脂酸、卵磷脂配比为75：20时效果最佳。所得SLN的包封率为82.67%,载药量为33.73%,平均粒径为461.3nm。     

Exploring solid lipid nanoparticles to enhance the oral bioavailability of curcumin

Scope : Curcumin, a molecule with pluripharmacological properties, was loaded into solid lipid nanoparticles (SLNs) with a view to improve its oral bioavailability (BA). Methods and results : Curcumin‐loaded solid lipid nanoparticles (C‐SLNs) with an average particle size of 134.6 nm and a total drug content of 92.33±1.63% was produced using a microemulsification technique. The particles were spherical in shape, with high drug entrapment of 81.92±2.91% at 10% drug loading. The in vitro release was predominantly by diffusion phenomenon and was prolonged up to 7 days. No significant variation in particle size and curcumin content of C‐SLNs was observed, upon storage, over a period of 12 months at 5±3°C. In vivo pharmacokinetics performed after oral administration of C‐SLNs (50, 25, 12.5 and 1 mg/kg dose) and (free) solubilized curcumin (C‐S; 50 mg/kg), using a validated LC‐MS/MS method in rat plasma revealed significant improvement (at p<0.05) in BA (39 times at 50 mg/kg; 155 times at 1 mg/kg; and, 59 and 32 times at 12.5 and 25 mg/kg, respectively) after administration of C‐SLNs at all the doses with respect to C‐S. Conclusions : Enhanced and reliable BA will help in establishing its therapeutic usefulness especially for neurodegenerative and cancerous disorders in humans.     

植物甾醇已二酸单酯的合成与固体纳米脂质粒的制备

以植物甾醇、己二酸为原料,二甲苯为溶剂,对甲苯磺酸为催化剂合成了植物甾醇己二酸单酯,并通过FT–IR、13C NMR、HPLC等分析手段证实了产物的结构;以植物甾醇己二酸单酯为原料,制备出固体纳米脂质粒。     

餐厨垃圾油制备油脂类固体燃料块的技术研究

利用餐厨垃圾油为原料,采用硬脂酸与固体石蜡组成的混合固定剂,通过催化酯化法,将餐厨垃圾油制备成燃烧性能良好的油脂类固体燃料块。通过条件优化,最终获得燃料块的最佳制备条件为:混合固定剂、餐厨垃圾油、与乙醇的最佳反应比为0.16∶1∶5;催化剂NaOH的最佳加入量为7.5 g,反应温度45℃,反应时间50 min。在最优条件下,利用食堂的餐厨垃圾油成功制备出性能良好的固体燃料块,产量最高可达103.6 g,燃烧残留率为6.5%,平均燃烧时间为94.0 s/g,均优于市场上常见的酒精块。     

Preparation and characterization of catalase-loaded solid lipid nanoparticles based on soybean phosphatidylcholine

BACKGROUND: High‐purity soybean phosphatidylcholine (SPC) (94%) were prepared using macroporous resin adsorption chromatography previously. Catalase is a food enzyme for promoting health and protecting against many age‐related disease. Solid lipid nanoparticles (SLN) are safe immobilizing systems for efficient protein transportation to biomembranes while avoiding adverse degradation of protein. This study was aimed at developing and characterizing catalase‐loaded SLN using SPC as solubilizers and stabilizing agents, to protect catalase from proteolysis. RESULTS: Catalase‐loaded SLN were prepared by the double emulsification method and solvent evaporation techniques, using acetone–methylene chloride (1:1, v/v) as an organic solvent, SPC–tripalmitin as oil phase and Poloxamer 188 as a surfactant. The optimized SLN were prepared using an SPC:tripalmitin ratio of 5% (w/w), 20 s plus 30 s sonication, 20 g L^?1 Poloxamer 188 and 1:2 (v/v) of oily phase:outer aqueous phase ratio. The mean particle size of SLN was 296.0 ± 7.0 nm, polydispersity index range and zeta potential were 0.322–0.354 and ? 36.4 ± 0.6, respectively, and encapsulation efficiency reached its maximum of 77.9 ± 1.56%. Catalase, which was found to distribute between the solid lipid and inner aqueous phase, was gradually released from SLN up to 20% within 20 h. Catalase‐loaded SLN had stably retained 30% of H₂O₂‐degrading activity for at least 24 h in a proteolytic environment, while free catalase lost its activity within 1 h. CONCLUSION: Catalase can indeed be loaded in tripalmitin‐based SLN using SPC as solubilizers and stabilizing agents, which protected it against proteolysis, suggesting the potential application of SPC in delivery and protection of functional food enzyme. Copyright © 2011 Society of Chemical Industry     

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.     

Formulation of sunscreens with enhancement sun protection factor response based on solid lipid nanoparticles

Solid lipid nanoparticle (SLN) was regarded as new topical delivery systems for pharmaceutical and cosmetic active ingredients. The purpose of this study is to develop carrier systems for organic and inorganic sunscreens based on a matrix composed of carnauba wax and decyl oleate. Formulae (F1–F7) were prepared using butyl methoxydibenzoylmethane and octyl methoxycinnamate as organic components, and titanium dioxide (TiO₂) was used as inorganic component. Both types of sunscreens were incorporated into SLN formulations using classical method of preparation. To evaluate the effect of the pigments on the nanoparticles, particle size was measured using Mastersizer particle size analyser. UV‐protection abilities of formulations were investigated by the in vitro sun protection factor test (SPF). Further parameters determined were spreadability as well as viscosity. The rheological behaviour of the formulations was also carried out. From the plot of log of shear stress vs. log of shear rate, the slope of the plot representing flow index and ontology of the y‐intercept indicating consistency index was calculated. The formulae showed a flow index of 0.2074–0.4005 indicating pseudoplastic flow behaviour. Significant increases in SPF values up to about 50 were reported after the encapsulation by using organic and inorganic filters in Canada wax and decyl oleate. So, SLN could be appropriate vehicles to carry organic and inorganic sunscreens. The rational combination of cinnamates, titanium dioxide and Zinc oxide has shown a synergistic effect to improve the SPF of cosmetic preparations.