Spray-dried Powders Research Articles

Characterization of Plant based spray dried powders using oil seed proteins and chokeberry extract from wine byproduct

Spray drying is a standard method for preserving bioactive ingredients and enhancing their storage stability. This study aimed to produce entirely plant-based spray-dried powders by using hemp, canola, and flax seed proteins, combined with maltodextrin, as wall material, while chokeberry extract from wine waste served as core material. We conducted a thorough analysis of the oil-seed proteins, examining their nitrogen solubility index, emulsification, and foaming capacities. The encapsulation process was evaluated based on its yield and efficiency. The spray-dried powders were further assessed through colour analysis, particle morphology and size distribution, hygroscopicity, and storage stability measurements. The encapsulation yield with oil-seed proteins ranged from 75.0 ± 6.2 to 78.5 ± 1.3%, and the efficiency from 58.4 ± 0.8 to 77.5 ± 1.9%. These plant-based spray-dried powders exhibited similar colour parameters, morphology, and stability to those of whey protein powders. The study highlights the significant potential of oil-seed proteins in producing plant-based spray-dried powders.

Differences in physicochemical properties and proteomics analysis of spray- and freeze-dried milk powders from bovine, goat, and horse sources

Milk powder, a nutrient-rich dairy product, lacks comprehensive information summarizing its specific properties when produced by spray- and freeze-dried technologies from different sources. Therefore, this study investigated the differences in physicochemical properties, microstructure, and proteome of spray- and freeze-dried milk powders from bovine, goat, and horse sources. The results revealed that spray-dried milk powder exhibited a smaller particle size, lower air content within the powder particles, inferior reconstitution properties, and lower lactose crystallinity compared with freeze-dried milk powder. Additionally, among the studied varieties, horse milk powder showed the lowest flowability but the most effective reconstitution properties. Proteomic analysis indicated that freeze-dried milk powder exhibited higher levels of immune-related proteins, including complement C3, C7, and complement factor B, and antimicrobial enzymes such as lysozyme and lactoperoxidase compared with spray-dried milk powder. Furthermore, specific milk powders contained more immune-related proteins such as serum amyloid A, myeloid antimicrobial peptide-28, polymeric immunoglobulin receptor, and mucin-1 compared with bovine milk powder. These findings contribute to a deeper understanding of the differences in the physical-chemical properties and potential biological functions of spray- and freeze-dried milk powders from various sources, which may help in further optimizing specific milk powder processing technologies.

Fast onset of thrombolytic effect of efficiently inhalable spray-dried rivaroxaban powder formulations

Pulmonary embolism is a critical medical condition and can lead to cardiovascular arrest or death if left untreated. Pulmonary delivery of an anti-coagulant therapeutic could provide a locally limited and efficient therapy, moreover combined with a potentially fast onset of the therapeutic effect that is demanded in emergency situations. Rivaroxaban (riva) was formulated as an inhalable dry powder that can be administered directly to the lungs in order to reach high local drug doses. Particles obtained spray drying dichloromethane-methanol mixtures yielded an aerodynamic diameter of about or smaller than 5 µm and were found to reach an emitted fine particle fraction (FPFEF) of at least 60 %. Pulmonary administration to rats using a dry powder insufflator revealed a nearly immediate therapeutic onset confirmed by the anticoagulant effects after 5 min in the plasma followed by a plateau over the next 4 h. Such rivaroxaban particles were further formulated in binary blends using different lactose carriers (Inhalac® 70/251/400). These interactive blends resulted in high emitted fractions of at least 87 %, and furthermore, the highest fine particle fraction − total dose (FPFTD) (60 %) of all tested formulations was achieved by using Inhalac® 400 as a carrier. The data strongly suggest a significant therapeutic potential of a rivaroxaban dry powder formulation, combining fast onset and a plateau of plasma concentrations turning it into a potential first aid therapeutic.

Advanced Spray-Dried Inhalable Microparticles/Nanoparticles of an Innovative Mitophagy Activator for Targeted Lung Delivery: Design, Comprehensive Characterization, Human Lung Cell Culture, and In Vitro Aerosol Dispersion Performance.

Urolithin A (UA) has demonstrated the ability to stimulate mitophagy and enhance mitochondrial and cellular health in skeletal muscles in humans after oral administration. It is hypothesized that targeted delivery of UA as inhaled dry powders to the lungs will enhance mitochondrial health through mitochondrial biogenesis. This study aimed to engineer inhalable excipient-free powders of UA as dry powder inhalers (DPIs) for targeted pulmonary delivery. The particles were designed by particle engineering from dilute organic solutions of UA using the state-of-the-art spray drying technology in a closed mode. Comprehensive physicochemical characterization and advanced microscopy techniques were conducted to examine phase behavior, molecular properties, and particle properties, which are necessary for the rational design of advanced pulmonary inhalation aerosols. Molecular fingerprinting was conducted by using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and Raman spectroscopy. Chemical imaging and mapping were conducted using confocal Raman microscopy (CRM) and IR microscopy. The advanced spray-dried (SD) excipient-free powders were successfully produced at different spraying pump feed rates and exhibited favorable molecular and particle properties. The excipient-free SD powders exhibited outstanding in vitro aerosol dispersion performance with an FDI-approved human DPI device (Neohaler) and correlated with the spray drying pump rate. In vitro, cell viability of various human pulmonary cells from different lung regions demonstrated biocompatibility and safety at different doses of UA. The transepithelial electrical resistance (TEER) assay shows that UA maintains cell membrane integrity and barrier tightness, indicating its potential for safe and effective localized drug delivery without long-term adverse effects. These results demonstrated that UA has favorable physicochemical and in vitro properties for inhalation and can be successfully engineered into excipient-free inhalable microparticles/nanoparticles as DPIs.

Physicochemical and Antioxidative Properties of Protein Hydrolysates from Residual Goat Placenta Extract by Two Different Methods.

Protein hydrolysates from the goat placenta provide multiple benefits, such as immune system enhancement, antioxidant activities, and reductions in uric acid levels. Despite these benefits, their industrial applications have been underexplored. This study aimed to prepare extract protein hydrolysates (GPERPs) from residual goat placenta extract (GPER) and assess their functional properties, focusing on how different drying methods influence these properties. The essential amino acid contents were 30.94% for the GPER and 34.11% for the GPERPs. Moreover, all the essential amino acids were present, and the amino acid score (AAS) for each exceeded 1.0 in the GPERPs. The foaming properties of the spray-dried GPERPs (95.56 ± 5.89%) were significantly greater than those of the freeze-dried GPERPs (49.13 ± 4.17%) at pH values of 4.0~10.0. The emulsion stability (ES) of the spray-dried GPERPs (453.44 ± 8.13 min) was notably greater than that of the freeze-dried GPERPs (245.58 ± 7.12 min). Furthermore, the water retention capacity (WRC) of the freeze-dried GPERPs (201.49 ± 6.12%) was significantly greater than that of the spray-dried GPERPs (103.35 ± 7.13%), except at pH 10.0 (101.44 ± 8.13%). Similarly, at pH values of 6.0, 8.0, and 10.0, the oil retention capacity (ORC) of the freeze-dried GPERPs (715.58 ± 12.15%) was significantly greater than that of the spray-dried GPERPs (560.56 ± 11.15%), although the opposite trend was noted under acidic conditions. In terms of the antioxidant activity, the ability of the goat placenta extract residual protein hydrolysates (GPERPs) to scavenge DPPH radicals and superoxide anion radicals increased with the increasing peptide powder concentration, and the maximum scavenging rates of the DPPH radicals (39.5 ± 0.56%) and superoxide anions (81.2 ± 0.54%) in the freeze-dried peptide powder were greater than those in the spray-dried peptide powder. These findings contribute to the understanding of the physicochemical and antioxidant properties of GPERPs under various drying methods and provide fundamental data for the development of functional foods based on GPERPs.

Optimization of ultrasonic-assisted debittering of Ganoderma lucidum using response surface methodology, characterization, and evaluation of antioxidant activity.

Ganoderma lucidum (G. lucidum) has gained increasing attention as a potential health care product and food source. However, the bitter taste of G. lucidum has limited its development and utilization for the food industry. The response surface methodology was employed to optimize the inclusion conditions for the debittering of G. lucidum. The effects of 2-hydroxypropyl-β-cyclodextrin concentration (12-14 g/mL), ultrasound temperature (20-40°C and host-guest ratio (1:1-2:1) on response variables were studied. The physical characteristics of inclusion complexes prepared through spray drying and freeze drying were analyzed. The antioxidant activity of the different treated samples was subsequently investigated. Study results showed that, in comparison to the control group, the inclusion solution displayed a significantly enhanced taste profile under optimal processing conditions, exhibiting an 80.74% reduction in bitterness value. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (NMR) studies indicated the successful formation of inclusion compounds. The moisture content and bulk density of spray-dried powder were found to be significantly superior to those of freeze-dried powder (p<0.05). In comparison to the diluted solution, the inclusion liquid demonstrated a 20.27%, 30.01% and 36.55% increase in ferric ion reducing antioxidant power (FRAP), hydroxyl radical scavenging and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging respectively. Further, the DPPH clearance of microencapsulated powder was not significantly different from that of tocopherol at a concentration of 25 mg/mL. In summary, the study provides theoretical basis and methodological guidance to eliminate the bitterness of G. lucidum, and therefore provide potential options to the use of G. lucidum as a food source.

Effects of spray drying and freeze drying on the protein profile of whey protein concentrate.

Whey protein concentrate (WPC) is consumed for its high protein content. The structure and biological functionality of whey proteins in WPC powders may be affected by the drying technique applied. However, the specific impact of spray drying and freeze drying on the overall protein profile of whey protein derived from sweet whey streams at scale is unknown. Herein, we examine the effects of commercial-scale freeze drying and spray drying on WPC to determine which method better preserves bioactive whey proteins, with the goal of helping the dairy industry create high-value products that meet the growing consumer demand for functional dairy products. WPCs were produced from pasteurized liquid whey using either a commercial spray dryer or freeze dryer. A variety of analytical techniques, including enzyme-linked immunosorbent assay, polyacrylamide gel electrophoresis, and bottom-up proteomics using liquid chromatography-tandem mass spectroscopy were used to identify, quantify, and compare the retention of bioactive proteins in WPC before and after spray drying and freeze drying. In addition, the extent of denaturation was studied via solubility testing, differential scanning calorimetry, and hydrophobicity assessment. There was little to no difference in the retention or denaturation of key bioactive proteins between spray-dried and freeze-dried WPC powders. There was a higher percentage of select Maillard modifications in freeze-dried and spray-dried powders than in the control. The lack of significant differences between spray drying and freeze drying identified herein indicates that freeze drying does not meaningfully improve retention of bioactive proteins compared with spray drying when performed after multiple pasteurization steps. PRACTICAL APPLICATION: This study aimed to provide insight into the impacts of spray drying versus freeze drying on whey proteins. Overall, our results indicate that for commercial dairy processing that involves multiple rounds of pasteurization, freeze drying does not meaningfully improve the retention of bioactive proteins compared with spray drying. These findings may help the food and dairy industry make informed decisions regarding the processing of its whey protein products to optimize nutritional value.

Effect of spray-drying or fermentation on the solubility and carbohydrate profile of chickpea hydrolysates for beverage formulation

Powder beverage bases were developed using extruded and hydrolyzed chickpea supernatant through freeze-drying. This study evaluated the effects of spray-drying and adjuvant incorporation for producing powders and supernatant fermentation with LAB strains prior freeze-drying on the carbohydrate composition, structural integrity, and physical properties of chickpea beverage base powders. All powders had low insoluble (<0.2%) and soluble (<3%) dietary fiber contents due to processing. Starch content decreased below 9.49% when using adjuvants and 10.61% during fermentation. Both treatments also reduce raffinose oligosaccharide content below 6.1 mM/100 g. Spray-drying and adjuvant addition promoted a more amorphous starch structure, enhancing solubility, while fermentation induced more crystallinity, according to FTIR data. Microscopy showed small particle clusters and lack of birefringence. SEM images revealed starch granule damage from both fermentation and spray-drying, with more uniform particles in spray-dried powders. Spray-drying resulted in the smallest particle sizes (455-457 nm) and higher absolute zeta potential (8.12-9.51), indicating greater stability. Fermentation had the opposite effect, negatively impacting the colloidal system stability. Samples had a pH close to 6, except fermented powders with a pH of 3.6, affecting colloidal stability. Fermentation significantly reduced solubility but without practical implications, as all samples had solubility values over 93%, which is desirable for beverage-based powders. Spray-drying and fermentation altered the carbohydrate profile and structure of the powders. Fermentation prior producing powders may provide benefits, but it slightly decreases the system stability. Spray-drying can be used instead of freeze-drying to produce stable chickpea base powders that are highly soluble.

Influence of L-leucine content on the aerosolization stability of spray-dried protein dry powder inhalation (DPI)

Inhalable formulations of medicines intended to act locally in the lung are therapeutically effective at lower doses with targeted delivery, compared to parenteral or oral administration. Meanwhile, different APIs, including biologics, have proven to be challenging regarding formulation and final bioavailability. This study focuses on the production, improved stability performance, and delivery of spray-dried, inhalable protein powders to the lungs. By spray-drying 11 aqueous formulations of proteinX with varying L-leucine content and by employing a Design of Experiment (DoE), two formulations have been selected for stability studies based on the highest fine particle fraction (FPF), highest monomer content, and lowest particle size. We found that 5 %w/w L-leucine (based on protein content) resulted in similar or higher FPF at 2–8 °C and 25 °C/60 %RH (67.12 % and 48.50 %) stored for six months than 10 %w/w L-leucine (68.49 % and 35.04 %). This indicates that less leucine may be sufficient to produce stable, spray-dried inhalable particles with an improved FPF, and by doubling the leucine content, the aerosolization stability can deteriorate. We have discussed the postulated hypothesis underlying the observed stability behavior based on solid-state and morphological analysis. Our results suggest that spray-dried proteinX-leu-powders can be delivered to the lung at a lower dose than for intravenous administration.

From plant to nanomaterial: Green extraction of nanomucilage from Cordia dichotoma fruit and its multi-faceted biological and photocatalytic attributes

This study aimed to evaluate the extraction efficiency of mucilage from Cordia dichotoma fruits using various aqueous extraction methods, including microwave-assisted water extraction (MWE), hot-water extraction (HWE), and cold-water extraction (CWE). Different analytical techniques were employed to characterize the Cordia dichotoma mucilage (CDM). Additionally, the functional properties, anti-microbial, anti-inflammatory, and dye reduction potential of CDM were assessed. The results indicated a significantly (p < 0.05) higher yield of CDM (13.44 ± 0.94 %) using MWE compared to HWE (12.08 ± 0.82 %) and CWE (7.59 ± 0.73 %). The optimal extraction condition was utilized for the spray-drying process, yielding a spray-dried mucilage powder (SDMP) with a yield of 9.52 ± 1.27 %. The presence of galactose and arabinose as major sugar and functional groups such as OH, COOH, CH, and NH from proteins, uronic acids, and sugars were identified. CDM predominantly comprises galactose and arabinose as major sugars. CDM particles exhibited an irregular morphology and demonstrated thermal stability, with maximum weight loss occurring between 221.83 and 478.66 °C. The particle size of CDM was 681.16 ± 2.18 nm with a zeta potential of −21.46 ± 1.72 mV. Rheological analysis revealed that CDM exhibits shear-thinning behavior. Furthermore, CDM displayed inherent biological activities, including antimicrobial and anti-inflammatory properties. The dye reduction potential of CDM was evidenced by an 88.67 % degradation of indigo carmine dye. In summary, this study provides insights into the cost-effective extraction methods for CDM and its potential utilization as an eco-friendly material for dye reduction.

Systematic screening of particle engineered polymers for the preparation of multiparticulates embedded orally disintegrating tablets

This paper evaluated polymers' physical and mechanical properties to formulate modified-release multiparticulates to be embedded in orally disintegrating tablets (ODTs). The targeted polymer should have adequate elastic-plastic properties in a multiparticulate system during the manufacturing process, which is affected by its physical properties. The good mechanical properties of the multiparticulate system can effectively aid in retaining the shape of the particles from being affected under applied compression pressure during the formulation process and tablets preparations. Therefore, the formulation should have good mechanical attains. Five polymers (three natural and two synthetic), namely: sodium alginate, polyvinyl alcohol (PVA), methylcellulose (MC), polyacrylic acid (PAA) and Eudragit L100, were evaluated. Polymers in raw form or particle engineered using spray drying were characterised using different analysis techniques: differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), compacts tensile strength, texture analysis, particle size analysis and surface area analysis. The unprocessed PAA exhibited the lowest Young's modulus, measuring at 5.38 MPa, whereas MC displayed the highest value of 14.74 MPa. The polymers were subjected to spray drying at a concentration of 5% w/v. Data of the texture analysis revealed that Young's modulus increased for the spray-dried PAA powder, reaching 13.69 MPa. This suggests an enhanced polymer compressibility subsequent to the spray drying process. Eudragit L100 demonstrated an enhanced tabletability prolife after spray drying. SEM and surface area results showed a correlation with the mechanical findings. Plasticity and elasticity together provide strong, durable tablets with structural integrity. Achieving a balance between these properties is crucial for effective tabletability. The results of this study provide an insight into physical and mechanical properties and changes encountered upon spray drying. A balance between elastic- plastic properties is required for optimal multiparticulate development.

Production and characterization of highly redispersible dried cellulose nanofibers exhibiting green color from leaves and stems of Centella asiatica

Several studies have demonstrated potential of cellulose nanofibers (CNF) in various applications. However, no protocols are available for the production of spray-dried CNF with high water redispersibility; interfibrillar hydrogen bonding that occurs during spray drying is believed to be responsible for such lack of redispersibility. The present study therefore aimed to develop a protocol that can be used to prepare CNF powders from Centella asiatica via spray drying, with maltodextrin (MD) at CNF-to-MD ratios of 1:0, 1:1, 1:1.5, 1:2 and 1:2.5 as the drying aid. Chlorophylls within such plant were also complexed with zinc in order to allow the resulting redispersed CNF to exhibit thermally stable green color. The resulting powders were analyzed for their morphology, XRD pattern and FTIR spectra to confirm the interaction between CNF and MD. Appropriate CNF-to-MD ratios were determined based on the sedimentation behavior, morphology, fiber sizes and viscoelasticity of the redispersed suspensions. Only spray-dried powders with CNF-to-MD ratios of 1:2 and 1:2.5 showed no sedimentation during the entire storage period. Suspensions prepared from the powders produced at these ratios were also capable of regaining morphology and nanofibrous widths (19–20 nm) comparable to those of freshly prepared CNF suspension, with gel-like behavior and viscoelasticity remained unchanged. Zinc-chlorophylls complex possessed thermal stability under the employed spray drying condition, as confirmed by the retention of chlorophylls in the powders. Green color of redispersed CNF suspensions was similar to that of freshly prepared CNF suspension.

Effect of lactic acid bacteria fermentation on spray-dried egg yolk powder: Powder characteristics, structural properties and gastrointestinal digestibility

Preparation of egg yolk powder with high solubility and high gastrointestinal digestibility is important for its effective utilization in the food industry. This study discovered that fermentation of egg yolks by lactic acid bacteria (LAB) resulted in a 54.3% increase in solubility, 110.6% increase in water dispersibility, and improved the stability of the dispersion to sedimentation. Fermentation resulted in smaller average particle size, enhanced hydrolysis of proteins and fats, and a more expansive protein structure in the egg yolk powder. Laser confocal microscopy showed increased hydrolysis of protein and fat in fermented egg yolk powder during simulated digestion, highlighting enhanced digestive properties due to LAB fermentation. This study validated the feasibility of LAB fermentation technology for modifying egg yolk powder, offering valuable insights for its processing and application in the food industry.

Redispersible dry powders containing nanoencapsulated curcumin increase its antioxidant activity

The present study aimed to develop redispersible spray-dried powders containing curcumin-loaded Eudragit® L100 nanocapsules and evaluate their physicochemical properties and antioxidant potential. The spray drying process showed a yield of over 85%, low residual moisture content (<2%), and all the physicochemical characteristics of the nanocapsules were recovered after the aqueous redispersion of the dry powders. In addition to the dry powders, the following samples were also analyzed: pure curcumin, pure lactose, and curcumin-lactose mix. In TGA and DSC analysis, all samples were thermostable and exhibited no chemical interactions with each other. In FTIR analysis, the nanostructured powder system showed functional groups of the precursors (curcumin and lactose), confirming the effectiveness in the preparation of the nanostructured material. In the evaluation of the free radical scavenging activity of DPPH•, the dry powder containing nanoencapsulated curcumin showed antioxidant activity approximately six times higher than free curcumin. Therefore, spray drying of nanoencapsulated curcumin made it possible to obtain a dry powder with homogeneous aqueous redispersion, as well as promoting the potentiation of the antioxidant activity of curcumin.

Effects of spray drying on the content of crystal proteins of Bacillus thuringiensis and the protection by organic and inorganic auxiliaries.

Spray drying is an important industrial method for the preparation of B. thuringiensis powder from fermentation liquor. The effect of spray drying on the crystal proteins, however, has not been reported in the literature so far. The present study systematically investigated the effect of inlet air temperature, outlet air temperature, atomizing air pressure and additives (including organic and inorganic auxiliaries) on the thermal destruction of crystal proteins of B. thuringiensis. The results indicated that the content of crystal proteins of B. thuringiensis powder decreased with increased inlet air temperature, outlet air temperature and atomising air pressure. The pseudo-z values for inlet air temperature, outlet air temperature and atomizing air pressure were 826.4℃, 204.0℃ and 4.74MPa, respectively. Among them, the outlet air temperature was a major parameter influencing the thermal destruction of crystal proteins, therefore, the decrease of the outlet air temperature was beneficial to increase the protein content in powder. Although the spray drying had an adverse effect on crystal proteins, the crystal protein content in spray-dried powder approached that in freeze-dried powder when the inlet air temperature of 165℃, outlet air temperature of 70℃ and atomizing air pressure of 0.15MPa were employed. The addition of some organic and inorganic auxiliaries to fermentation liquor can protect the crystal proteins from heat damage.

Innovative utilization of olive mill wastewater phenolics extracted by lecithin: spray-dried powders in cake formulations

In the present study, the olive mill wastewater (OMW) phenolics were extracted with soy lecithin using the cloud point extraction method, and this enriched lecithin (OMW-L) was converted into spray-dried powders using maltodextrin (MD) and whey protein concentrate to be utilized as a dry food ingredient in a cake premix. The inlet temperature of 170 °C and a 3 mL/min feed flow rate yielded the highest powder yield (70.88 ± 2.12%) with a moisture content of 3.78 ± 0.03% when the mass ratio of lecithin to MD was 1:3 (w:w). The hydroxytyrosol and tyrosol contents of the powder were 42.60 ± 4.51 mg/100 g and 15.48 ± 2.50 mg/100 g, respectively. Vanillic acid, caffeic acid, 3-hydroxybenzoic acid, catechin, and rutin were also identified in the powders. The spray-dried OMW-L powder with a higher loading of polyphenols was then used in a cake premix, replacing 1% and 3% of wheat flour. This substitution significantly reduced the K value of the cake batter, as determined by rheological analyses. The addition of spray-dried OMW-L powder to the cake samples, particularly at higher concentrations (3%), influenced both crust and crumb color, causing changes in L*, a*, and b* values. The hardness values of the cake samples did not alter when blank or OMW-enriched lecithin powders were added; rather, the hardness value was influenced by the powder content. Overall, this research offers a different perspective on the use of OMW phenolics in food applications, especially in ready-to-use blends, and demonstrates the effects of the obtained spray-dried lecithin powders on batter rheology and cake characteristics.Graphical abstract

Non-Invasive, Continuous, Quantitative Detection of Solvent Content in Vacuum Tray Drying

A non-invasive capacitance instrument was embedded in the base of a vacuum-drying tray to monitor continuously the residual amount of solvent left in a pharmaceutical powder. Proof of concept was validated with Microcrystalline Cellulose laced with water, as well as water/acetone mixtures absorbed in a spray-dried Copovidone powder. To illustrate the role of impermeability of the base, we derive a model of vapor sorption that reveals the existence of a kinetic limit when solids are thinly spread, and a diffusion limit with greatly diminished effective diffusivity at large powder thickness. By monitoring the residual solvent content of powders, this new in situ technique offers advantages over indirect methods like mass spectrometry of vapor effluents, but without complications associated with probe fouling. To prescribe design guidelines and interpret signals, we model the electric field shed by the probe when a powder holds variable solvent mass fraction in the vertical direction.Graphical abstract

Formulation of three tailed bacteriophages by spray-drying and atomic layer deposition for thermal stability and controlled release

Deep infection is the second most common complication of arthroplasty following loosening of the implant. Antibiotic-loaded bone cements (ALBCs) and high concentrations of systemic broad-spectrum antibiotics are commonly used to prevent infections following injury and surgery. However, clinical data fails to show that ALBCs are effective against deep infection, and negative side effects can result following prolonged administration of antibiotics. Additionally, the rise of multidrug resistant (MDR) bacteria provides an urgent need for alternatives to broad-spectrum antibiotics. Phage therapy, or the use of bacteriophages (viruses that infect bacteria) to target pathogenic bacteria, might offer a safe alternative to combat MDR bacteria. Application of phage therapy in the setting of deep infections requires formulation strategies that would stabilize bacteriophage against chemical and thermal stress during bone-cement polymerization, that maintain bacteriophage activity for weeks or months at physiological temperatures, and that allow for sustained release of phage to combat slow-growing, persistent bacteria. Here, we demonstrate the formulation of three phages that target diverse bacterial pathogens, which includes spray-drying of the particles for enhanced thermal stability at 37 °C and above. Additionally, we use atomic layer deposition (ALD) to coat spray-dried powders with alumina to allow for delayed release of phage from the dry formulations, and potentially protect phage against chemical damage during bone cement polymerization. Together, these findings present a strategy to formulate phages that possess thermal stability and sustained release properties for use in deep infections.

Obtaining coffee mucilage microcapsules by spray drying using chemically modified banana starch

The growing global consumption of coffee has positioned Colombia as the third largest producer worldwide. However, the processing of coffee beans generates significant by-products, such as mucilage, which is rich in phenolic compounds with antioxidant activity. Inadequate disposal of this waste creates environmental problems and economic losses. This research aimed to develop high-quality coffee mucilage capsules using spray drying technology. Chemically modified banana starch with octenyl succinic anhydride (OSA) and commercial maltodextrin were used as coating materials to enhance the properties of the capsules. Physicochemical and functional characterization was performed on samples of fresh and filtered coffee mucilage (MF), concentrated mucilage (MC), concentrated mucilage with the addition of maltodextrin and OSA-modified starch (MCMA), and finally, spray-dried coffee mucilage powder (MP). The antioxidant capacity (AC) of the mucilage was evaluated throughout the processing stages. MF showed an AC of 179.2 µmol of trolox/100 g, while the final coffee mucilage powder (MP) showed a significantly higher AC of 5444.35 µmol of trolox/100 g. Additionally, the MP showed a stability index of 0.48, water activity (aw) of 0.19, solubility of 14.64%, and a high water retention capacity of 90.53%. Microscopic analysis revealed amorphous structures with an average size of 29.16 ± 2.12 µm in the MP. These findings highlight the potential of spray drying with food-grade matrices such as OSA-modified banana starch to encapsulate coffee mucilage, preserving its antioxidant capacity and creating a new functional food ingredient with water retention properties.

Phenomenological model of moisture redistribution in porcelain stoneware spray-dried powder stored in silo

Porcelain stoneware powder requires at least 24 h of silo storage to stabilize temperature and moisture content after spray-drying. Homogeneity is crucial to produce dimensionally stable tiles. The objective was to model moisture redistribution in granules of different sizes using phenomenological formulation. An original multiscale approach incorporated segregation into the coupled mass/heat transfer equations. Finite element method numerically solved and accurately estimated moisture content in fines, intermediate, and coarse granules in accordance with industrial data. The starting moisture content difference of 3.19% between coarse and fine granules was reduced to 1.62% and 0.88% for 24 h and 48 h storage times, respectively. Output temperature estimates agreed with measurements (maximum error of 17%). Higher thermal gradients evidenced the cooling effect as moisture content increased in all granules at the wall, observed as condensed water in the actual system. This model could be applied to any material in storage within a center-filled silo.