Freeze-dried Particles Research Articles

Blueberry polyphenol-protein food ingredients: The impact of spray drying on the in vitro antioxidant activity, anti-inflammatory markers, glucose metabolism and fibroblast migration

Wild blueberry pomace extract complexed with wheat or chickpea flour or soy protein isolate produced spray dried and freeze-dried polyphenol-protein particles. To evaluate the impact of spray drying on the biological activity of these food ingredients in vitro antioxidant and anti-inflammatory activities, regulation of glucose metabolism and ability to stimulate fibroblast migration were tested. Extracts from polyphenol-protein particles significantly decreased reactive oxygen species (ROS) production and down-regulated the gene expression of inflammation markers (COX-2 and IL-1β). Milder suppression of nitric oxide production and inducible nitric oxide synthase (iNOS) gene expression was evident. The extracts significantly inhibited phosphoenolpyruvate carboxykinase (PEPCK) and accelerated fibroblast cell migration up to 3-fold after 24 h. Complexed polyphenols retained their structural integrity and bioactive potency for both lyophilized and spray dried treatments. The data suggests that spray drying is a convenient and cost-effective technique to produce blueberry-polyphenol food ingredients with preserved phytochemicals with biological activities.

Obtaining functional powder tea from Brazilian ginseng roots: Effects of freeze and spray drying processes on chemical and nutritional quality, morphological and redispersion properties

In this work, the aqueous extract obtained from Brazilian ginseng (Pfaffia glomerata) roots (BGR), rich in beta-ecdysone and fructooligosaccharides (FOS), was powdered by spray drying and freeze drying techniques aiming to obtain a novel functional food product. The effects of these drying techniques on the chemical and nutritional quality, morphological and redispersion properties of the BGR powders were evaluated. The BGR powders obtained by both spray drying and freeze drying techniques maintained their beta-ecdysone and FOS contents after drying, demonstrating the stability of these functional compounds. It was found that the wettability of the powders obtained by different treatments was affected by the drying technique because freeze-dried particles reached the lower values (66 ± 5 s) while spray-dried particles showed a greater time for dispersion into water (150 ± 25 s). This behavior was mainly associated with differences between powder morphological properties since the freeze-dried particles presented a more porous structure, resulting in a greater water diffusivity into microstructure during the redispersion process. Drying process did not affect the storage stability of powders because the glass transition temperature (Tg) for both samples was approximately 160 °C at a relative humidity of 56%. Thus, both BGR powders presented adequate redispersion properties to constitute a new functional tea or even to be used as a functional ingredient in food products.

Application of spray chilling and electrostatic interaction to produce lipid microparticles loaded with probiotics as an alternative to improve resistance under stress conditions

Probiotics were enumerated in each step of the encapsulation process and the resistance of encapsulated microorganisms was verified under stress (temperature, pH, sodium chloride and sucrose) and simulated gastrointestinal conditions (SGC). Lipid particles were effective in protecting the probiotics subjected to environmental stress conditions (ESC) and SGC, when compared to free cells. After 30 days of storage at 25 °C, the viability of probiotics encapsulated by spray chilling was about 7.2 log cfu/g, while in the freeze-dried lipid particles covered by gelatin and gum Arabic the viability of probiotics was approximately 6.7 log cfu/g. Both encapsulation methods investigated were successful in protecting the probiotics in SGC and ESC, indicating their potential for application in food. However, the viability of encapsulated probiotics during storage must still be improved.

Effect of amino acids on the stability of spray freeze-dried immunoglobulin G in sugar-based matrices

The purpose of this study was to prepare spray freeze-dried particles of immunoglobulin G (IgG) using various combinations of trehalose and different amino acids (leucine, phenylalanine, arginine, cysteine, and glycine), and investigate the effect of the amino acids on the stability of IgG during the spray freeze-drying (SFD) process and storage. The morphology and structural integrity of the processed particles were evaluated by physical and spectroscopic techniques. SFD-processed IgG without any excipient resulted in the formation of aggregates corresponding to approximately 14% of IgG. In contrast, IgG formulations stabilized using an optimal level of leucine, phenylalanine, or glycine in the presence of trehalose displayed aggregates <2.2%. In particular, phenylalanine combined with trehalose was most effective in stabilizing IgG against shear, freezing, and dehydration stresses during SFD. Arginine and cysteine were destabilizers displaying aggregation and fragmentation of IgG, respectively. Aggregation and fragmentation were evaluated by dynamic light scattering, ultraviolet spectrophotometry, size-exclusion chromatography, and microchip capillary gel electrophoresis. The IgG formulations prepared with leucine, phenylalanine, or glycine in the presence of trehalose showed good stability after storage at 40 °C and 75% relative humidity for 2 months. Thus, a combination of the excipients trehalose and uncharged, nonpolar amino acids appears effective for production of stable SFD IgG formulations.

Characteristics of eugenol loaded chitosan-tripolyphosphate particles as affected by initial content of eugenol and their in-vitro release characteristic

The aim of this research was to determine encapsulation efficiency, loading capacity and controlled release of eugenol loaded chitosan-tpp products which prepared by coaservation method. The characteristic of eugenol-loaded chitosan showed that %EE and % LC increased by increasing the initial eugenol content. The optimum of %EE (72.63%) and %LC (43.96%) were obtained at the ratio of chitosan to eugenol of 1:1.5. The FTIR spectrum showed the characteristic peaks of eugenol appearing on spectrum of eugenol encapsulated and blue-shift in the hydroxyl band from 3425.58 cm-1 in chitosan-tpp to 3417.86 cm-1 and 3394.72 cm-1 in eugenol loaded chitosan-tpp indicating that eugenol was successfully encapsulated. The surface morphologies of freeze-dried particles with the optimum %EE showed that more surface roughness and porosity than plain particles. Furthermore, the in vitro release of particles with minimum and optimum %EE were also investigated in acid (Simulated Gastric Fluid) and base (Simulated Intestinal Fluid) medium at ambient temperature.

Particle size characteristics of buriti oil microcapsules produced by gelatin-sodium alginate complex coacervation: Effect of stirring speed

ABSTRACTThe influence of hydrodynamic conditions in the coacervation medium of the carotenoid-rich buriti oil using gelatin-alginate as wall materials was investigated. The stirring speed had strong influence on the size of the microcapsules, and Reynolds number higher than 70000 resulted in particle size D[4,3] lower than 200 μm. The carotenoid encapsulation efficiency was around 80%, with freeze-dried particles presenting intense yellow color. Although the size of the microparticles was highly dependent on the hydrodynamic conditions during coacervate formation, complex coacervation of gelatin and sodium alginate showed to be a feasible process to producing buriti oil microcapsules.

Effect of composition and drying method on glass transition temperature, water sorption characteristics and surface morphology of newly designed \u03b2-lactoglobulin/retinyl palmitate/disaccharides systems

In the study, MDSC method was used to evaluate thermal properties of β-lactoglobulin–retinyl palmitate products enriched in disaccharides. Additionally, sorption behavior of powders was determined to define their stability. The obtained powders were also examined and visualized with scanning electron microscopy to find the relationship between food processing conditions and morphological changes in products. For the samples tested, a single glass transition was observed. The results have shown the impact of the composition of studied samples on the glass transition temperatures. The carbohydrate- β-lactoglobulin systems were characterized by higher Tg values than disaccharides alone. At low water activity, all powdered complexes showed typical sorption behavior of food systems with the sigmoidal shape of the curve. The present study has shown that spray-dried and freeze-dried powdered products with lactose or trehalose have different time-dependent crystallization behavior. Trehalose as a carbohydrate component of samples, in comparison with lactose, delayed the occurrence of crystallization. The obtained images presented the dependence of the shape of the particles on the drying method used. Spray-dried powders were characterized by a spherical or close to spherical structure with the surface of larger particles often deformed. In the case of freeze-dried particles, irregular structures were observed.

Effect of drying technique and particle size of bilberry press cake on the extraction efficiency of anthocyanins by pressurized carbon dioxide extraction

To improve the extraction efficiency of anthocyanins from bilberry press cake using pressurized carbon dioxide, the combined effect of drying technique and bilberry press cake particle size was assessed. Pressurized carbon dioxide using ethanol as co-solvent was compared with a simple and efficient solvent extraction using methanol. The press cake with large (>710 μm) size particles had a higher anthocyanins content (84 g/kg dry matter to 87 g/kg dry matter) than did the small (<710 μm) size particles (60 g/kg dry matter to 65 g/kg dry matter). Although, the large size particles contained more anthocyanins, more efficient anthocyanins extraction using pressurized carbon dioxide extraction was obtained with the small than the large size particles. The press cake dried by freeze-drying generated a powder with smaller particles and lower bulk density than either the microwave-assisted hot-air-dried or hot-air-dried powders. In comparison to methanol extraction, the most efficient anthocyanins extraction was obtained from the freeze-dried small size particles. This work showed that there is a potential to improve the extraction efficiency of anthocyanins extracted by pressurized carbon dioxide by selecting appropriate drying technology and particle size distribution of the press cake.

Application of combinational supercritical CO2 techniques to the preparation of inhalable particles

This study describes a supercritical CO2 (scCO2) system, which combines supercritical antisolvent (SAS) and rapid expansion from supercritical to aqueous solution (RESAS) processes, enabling the preparation of a poorly water-soluble drug (ONO-2921) as a dry powder for inhalable formulations. The SAS unit disperses the drug solution in scCO2 and the RESAS unit sprays the drug dispersion into water. Dispersing the ethanolic drug solution into a vessel purged with scCO2 practically eliminated crystallization of ONO-2921 when the CO2 pressure was more than 15 MPa at 40 °C. In contrast, a suspension containing submicron-sized particles was obtained when the scCO2-drug mixture was sprayed into water using a RESAS device. Suspensions were freeze-dried to create powdered samples for determining in vitro inhalation properties. Freeze-dried particles processed with 25 MPa of CO2 at 40 °C showed 24-fold greater deposition in the stage 2 fraction of the twin impinger than raw ONO-2921. The fine particle fraction value (aerodynamic diameter <4.7 μm) of its processed sample was 48.7% ± 0.6%. As this scCO2 approach does not require additives or excipients to prepare the particles, the pulmonary delivery of large amounts of ONO-2921 as an inhalable dry powder represents an attractive drug delivery system.

The role of counter ions in nano-hematite synthesis: Implications for surface area and selenium adsorption capacity

Nano metal oxides are of interest for aqueous selenium (Se) remediation, and as such, nano-hematite (nα-Fe2O3) was examined for use as a Se adsorbent. The effect of surface area on adsorption was also studied. nα-Fe2O3 particles were synthesized from Fe(NO3)3 and FeCl3 via forced hydrolysis. The resulting particles have similar sizes, morphologies, aggregate size, pore size, and PZC. The nα-Fe2O3 from FeCl3 (nα-Fe2O3-C) differs from the nα-Fe2O3 from Fe(NO3)3 (nα-Fe2O3-N) with a ∼25±2m2/g greater surface area. Selenite Se(IV) adsorption capacity on nα-Fe2O3 has a qmax ∼17mg/g for the freeze-dried and re-suspended nα-Fe2O3. The Δqmax for nα-Fe2O3 from Fe(NO3)3 and FeCl3 that remained in suspension was 4.6mg/g. For selenate Se(VI), the freeze-dried and re-suspended particles realize a Δqmax= 1.5mg/g for nα-Fe2O3 from Fe(NO3)3 and FeCl3. The nα-Fe2O3 from Fe(NO3)3 and FeCl3 that remained in suspension demonstrated Se(VI) Δqmax=5.4mg/g. In situ ATR–FTIR isotherm measurements completed for Se(VI) at a pH 6 suggest that Se(VI) forms primarily outer–sphere complexes with nα-Fe2O3 synthesized from both salts.

Systemic delivery of parathyroid hormone (1–34) using spray freeze-dried inhalable particles

Pulmonary delivery of peptides remains an important, noninvasive route of administration that is attractive because it offers high bioavailability and patient compliance. Optimization of particle characteristics for deposition in the deep regions of the lung after inhalation and retention of peptide stability are key challenges to their delivery to the lungs. The present study investigated the use of spray freeze-drying to produce porous inhalable parathyroid hormone (1–34)-loaded microparticles suitable for pulmonary delivery. The influence of different excipients in the medium of water or citrate buffer on microparticles characteristics, peptide stability and its systemic delivery in rats were evaluated. Using leucine at 10% (w/w) and hydroxy propyl-β-cyclodextrin (HPβCD) at 0.04% (w/w) in water or citrate medium preserved parathyroid hormone (1–34) stability by spray freeze-drying. Aerosol performance showed that leucine was more effective than HPβCD in producing inhalable microparticles. Nevertheless, there was no statistical difference between bioavailabilities of HPβCD containing formulations and leucine-containing formulations in the presence of citrate buffer; and even in the presence of water, HPβCD resulted in higher bioavailability compared to leucine. The high absolute bioavailability (up to 47.25%) of formulations could facilitate replacement of injected form of parathyroid hormone (1–34) by dry powder inhaler form.

Oral application of freeze-dried yeast particles expressing the PCV2b Cap protein on their surface induce protection to subsequent PCV2b challenge in vivo

Porcine circovirus type 2 (PCV2) is now endemic in every major pig producing country, causing PCV-associated disease (PCVAD), linked with large scale economic losses. Current vaccination strategies are based on the capsid protein of the virus and are reasonably successful in preventing PCVAD but fail to induce sterile immunity. Additionally, vaccinating whole herds is expensive and time consuming. In the present study a “proof of concept” vaccine trial was employed to test the effectiveness of powdered freeze-dried recombinant Saccharomyces cerevisiae yeast stably expressing the capsid protein of PCV2b on its surface as an orally applied vaccine. PCV2-free pigs were given 3 doses of vaccine or left un-vaccinated before challenge with a defined PCV2b strain. Rectal temperatures were measured and serum and faeces samples were collected weekly. At the end of the study, pigs were euthanized, tissue samples taken and tested for PCV2b load by qPCR and immunohistochemistry. The peak of viraemia in sera and faeces of unvaccinated pigs was higher than that of vaccinated pigs. Additionally more sIgA was found in faeces of vaccinated pigs than unvaccinated. Vaccination was associated with lower serum concentrations of TNFα and IL-1β but higher concentrations of IFNα and IFNγ in comparison to the unvaccinated animals. At the end of the trial, a higher viral load was found in several lymphatic tissues and the ileum of unvaccinated pigs in comparison to vaccinated pigs. The difference between groups was especially apparent in the ileum. The results presented here demonstrate a possible use for recombinant S. cerevisiae expressing viral proteins as an oral vaccine against PCV2. A powdered freeze-dried recombinant S. cerevisiae used as an oral vaccine could be mixed with feed and may offer a cheap and less labour intensive alternative to inoculation with the additional advantage that no cooling chain would be required for vaccine transport and storage.

Encapsulation of resveratrol into Ca-alginate submicron particles

Resveratrol-loaded alginate submicron particles were prepared by emulsification followed by external gelation. Scanning electron microscopy analysis of the air-dried and freeze-dried submicron particles demonstrated their spherical shape, from 100nm to 600nm in size. The encapsulation efficiency and loading for resveratrol were 24.5% (±1.6%) and 0.3% (±0.05%), respectively. The interactions between the encapsulated resveratrol and alginate were characterised by Fourier transform infrared spectroscopy and differential scanning calorimetry. The release from the alginate submicron particles was successfully described by the linear superimposition model, which allowed concluding that resveratrol transport is governed by Fick’s diffusion. The alginate submicron particles were prepared from materials that are considered as generally recognized as safe, and thus have good potential for use as a resveratrol delivery system in food products.

Dextran-based hydrogel microspheres obtained in w/o emulsion: preparation, characterisation and in vivo studies

The cross-linking reaction in w/o emulsions of dextran (DEX) functionalised with methacrylic groups, having or not acid residues in side chain, can be used to easily prepare polysaccharide hydrogel microspheres with properties suitable for drug delivery applications. The formation of a chemical network within the obtained particles was evaluated with FT-IR spectroscopy, whereas morphology and dimensions of the microspheres were investigated with optical and scanning electron microscopy. At the same time, swelling measurements were carried out on freeze-dried particles in different aqueous media simulating biological fluids. Preliminary release experiments performed with ibuprofen, betamethasone and vitamin B12 chosen as model drugs, showed that these microspheres could be suitable as modified drug delivery systems in oral formulations. Finally, in vivo writhing experiments were carried out in mice in order to verify the antinociceptive activity of betamethasone loaded into the new polysaccharide hydrogel microspheres.

Characterization of the Dynamic Thickness of the Aerobic Layer during Pig Manure Aerobic Composting by Fourier Transform Infrared Microspectroscopy

A new method for characterizing the aerobic layer thickness in pig manure based on Fourier transform infrared microspectroscopy (FTIRM) is presented to improve the anaerobic/aerobic co-process mechanism, to ensure adequate oxygen supply and, thus, minimize methane emissions during aerobic composting. Freeze-dried manure particles were microtomed into 10 μm thick sections; the spectral range, spectral resolution, and pixel dimensions in the transmission spectra were 4000-650 cm(-1), 16 cm(-1), and 6.25 × 6.25 μm, respectively. A mean spectrum of 16 scans was used for the second-derivative analysis with nine smoothing points. This is the first attempt at determining the oxidation profile of composting particles according to the radial variations in second-derivative spectra at 2856 and 1568 cm(-1), which are attributed to the reactants and products of the oxidation, respectively. In addition, an intermediate area is detected between the aerobic layer and anaerobic core. The experimental values of the aerobic layer thickness are consistent with the estimates, and an exponential increase is observed, which is influenced by multiple dynamic factors. However, the contribution of each factor to dynamic variations in the aerobic layer thickness should be investigated using available methods.

Comparison of Stability between Kaso (Tetracarpidium conophorum) and Safou Pulp (Dacryodes edulis) Oils Encapsulated in Maltodextrins 6DE

Safou pulp and Kaso oils have a good nutritional value and olive oil's properties are well known. Totox value and the content of thiobarbituric reactive species were measured over a period of 2 months, at 50°C, to evaluate oxidation of free and maltodextrin-encapsulated oils. Freeze-dried particles were more efficient against oil oxidation than spray-dried particles. The comparison between Safou and Kaso using olive oil as reference demonstrates the best oxidative stability of this first one at 50°C. These oils stored over 3 years at 20°C showed the high amount of Peroxide value and modifications of the fatty acid fraction and composition.

Development of lyophilized spherical particles of poly(epsilon-caprolactone) and examination of their morphology, cytocompatibility and influence on the formation of reactive oxygen species

A common limitation of using polymeric micro and nanoparticles in long-term conservation is due to their poor physical and chemical stability. Freeze-drying is one of the most convenient methods that enable further reconstitution of micro and nanoparticles for therapeutical use. Nevertheless, this process generates various stresses during freezing and desiccation steps. This paper underlines the combined outcomes of freeze drying method and physicochemical solvent/non-solvent approach to design biocompatible poly(epsilon-caprolactone) (PCL) nanospheres and evaluate influence of different cryoprotectants (glucose, saccharose, polyvinyl alcohol or polyglutamic acid) on the outcome of freeze-dried PCL particles. Samples were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and dynamic light scattering method (DLS). In vitro studies used, include MTT assay (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), testing cytotoxicity as the quality of being toxic to cells, and DCFH-DA assay (2’,7’-dichlordihydrofluorescein-diacetate), testing the possible increase in ROS levels. It was found that cryoprotection with 1% glucose solution is an optimal for obtaining uniform, spherical but also biocompatible PCL nanoparticles for biomedical purposes.

Design andIn VitroEvaluation of a New Nano-Microparticulate System for Enhanced Aqueous-Phase Solubility of Curcumin

Curcumin, a yellow polyphenol derived from the turmeric Curcuma longa, has been associated with a diverse therapeutic potential including anti-inflammatory, antioxidant, antiviral, and anticancer properties. However, the poor aqueous solubility and low bioavailability of curcumin have limited its potential when administrated orally. In this study, curcumin was encapsulated in a series of novel nano-microparticulate systems developed to improve its aqueous solubility and stability. The nano-microparticulate systems are based entirely on biocompatible, biodegradable, and edible polymers including chitosan, alginate, and carrageenan. The particles were synthesized via ionotropic gelation. Encapsulating the curcumin into the hydrogel nanoparticles yielded a homogenous curcumin dispersion in aqueous solution compared to the free form of curcumin. Also, the in vitro release profile showed up to 95% release of curcumin from the developed nano-microparticulate systems after 9 hours in PBS at pH 7.4 when freeze-dried particles were used.

Management of massive acetabular bone defects using a mixture of autograft and freeze-dried allograft bone combined with acetabular scaffold

Objective To investigate the role of hybrid bone grafting using autograft and freezedried allograft bone in restoration of acetabular bone defect,as well as to evaluate the clinical results of this grafting technique combined with acetabular scaffold in dealing with massive acetabular deficiency.Methods Between April 1999 to December 2007,18 patients (19 hips) underwent acetabular revision by using a mixture of autograft and allogenic freeze-dried cancellous bone particles plus acetabular scaffold.There were 8males and 10 females,aged from 33 to 76 years (average,64.7 years).The acetabular defects were caused by aseptic loosening of primary total hip arthroplasty in 17 patients and osteoarthritis secondary to osteotomy in 1 case of acetabular dysplasia.There were 5 cases of Paprosky Ⅱ B defect,2 Paprosky Ⅱ C defect,6 Paprosky ⅢA defect and 6 Paprosky ⅢB defect.Results All patients were followed up for 3.6 to 12.3 years (average,6.5 years).Harris hip score improved from preoperative 38.7±9.6 to 87.6±7.8 at final follow-up.According to X-rays,bone incorporation evidenced by trabecular bridging of the host-donor interface was found at 3to 6 months postoperatively,and effective bone incorporation was achieved in all cases one year postoperatively.Polyethylene wear occurred in one case.Acetabular component loosening was not found at final follow up.Conclusion Impacted bone grafting using a mixture of autograft and freeze-dried allograft bone can efficiently restore acetabular bone defect.Adding autograft bone to freeze-dried allograft bone is a highly effective way of achieving graft incorporation.Hybrid bone grafting technique with acetabulum scaffold is an attractive option for the treatment of extensive acetabular deficiency. Key words: Acetabulum; Bone transplantation; Arthroplasty,replacement,hip; Reoperation

Immobilization of protein-coated drug nanoparticles in nanofibrillar cellulose matrices—Enhanced stability and release

Nanosizing is an advanced approach to overcome poor aqueous solubility of active pharmaceutical ingredients. One main problem in pharmaceutical nanotechnology is maintaining of the morphology of the nanometer sized particles during processing and storage to make sure the formulation behaves as originally planned. Here, a genetically engineered hydrophobin fusion protein, where the hydrophobin (HFBI) was coupled with two cellulose binding domains (CBDs), was employed in order to facilitate drug nanoparticle binding to nanofibrillar cellulose (NFC). The nanofibrillar matrix provides protection for the nanoparticles during the formulation process and storage. It was demonstrated that by enclosing the functionalized protein coated itraconazole nanoparticles to the external nanofibrillar cellulose matrix notably increased their storage stability. In a suspension with cellulose nanofibrils, nanoparticles around 100 nm could be stored for more than ten months when the specific cellulose binding domain was fused to the hydrophobin. Also freeze-dried particles in the cellulose nanofibrils matrix were preserved without major changes in their morphology. In addition, as a consequence of formation of the immobilized nanodispersion, dissolution rate of itraconazole was increased significantly, which also enhanced the in vivo performance of the drug.