Spray-dried Powders Research Articles

A Design of Experiment Approach to Optimize Spray-Dried Powders Containing Pseudomonas aeruginosaPodoviridae and Myoviridae Bacteriophages.

In the present study, we evaluated the effect of spray-drying formulations and operating parameters of a laboratory-scale spray-dryer on the characteristics of spray-dried powders containing two Pseudomonas aeruginosa bacteriophages exhibiting different morphotypes: a podovirus (LUZ19) and a myovirus (14-1). We optimized the production process for bacteriophage-loaded powders, with an emphasis on long-term storage under ICH (international conference on harmonization) conditions. D-trehalose-/L-isoleucine-containing bacteriophage mixtures were spray-dried from aqueous solutions using a Büchi Mini Spray-dryer B-290 (Flawil, Switzerland). A response surface methodology was used for the optimization of the spray-drying process, with the following as-evaluated parameters: Inlet temperature, spray gas flow rate, and the D-trehalose/L-isoleucine ratio. The dried powders were characterized in terms of yield, residual moisture content, and bacteriophage lytic activity. L-isoleucine has demonstrated a positive impact on the activity of LUZ19, but a negative impact on 14-1. We observed a negligible impact of the inlet temperature and a positive correlation of the spray gas flow rate with bacteriophage activity. After optimization, we were able to obtain dry powder preparations of both bacteriophages, which were stable for a minimum of one year under different ICH storage conditions (up to and including 40 °C and 75% relative humidity).

Exploration of modified cyclone separator for the enhanced recovery of inhalable spray dried cubosomal powder intended to be used for lung delivery

The study was conducted with the aim to fabricate a cyclone separator capable of providing cubosomal powder with enhanced recovery, uniform size, and high aerosolization efficiency. For that purpose, Classical cyclone design (CCD) and Texas cyclone design (TCD) process parameters (number of effective turns (Ne), inlet air velocity (Vi), pressure drop (ΔP), and cut point diameter (dpc)) were utilized to obtained five geometrical parameters (length of cyclone body (Lb), length of cyclone cone (Lc), height (H) and width (W) of inlet section and air exit diameter (De)) of modified cyclone (type XVII). The design analysis predicted the lowest dpc of 1.5 μm along with an enhanced amount of cubosomal powder collection. The Design of Experiment (DoE) and Signal to Noise (S/N) ratio were employed to evaluate the effect of formulation, process parameter, and cyclone design on device removal efficiency, aerosolization efficiency, fine particle fraction, and yield of cubosomal powder. The modified cyclone provides 1.8 fold enhanced cubosomal powder recovery, which has been associated with increased ΔP inside the cyclone separator. The optimized inhalable spray-dried cubosomal powder possess a sufficient geometrical diameter (dG) (3.9 ± 0.25 μm) and aerodynamic diameter (dA) (2.04 ± 0.15 μm) to deliver formulation to deeper lung tissues. Overall, the findings pointed towards the industrial benefits of developed cyclone design as it experimentally provides enhanced recovery of cubosomal powder in the size range of 1–5 μm with its desirable aerosolization properties.

Improvement of Resveratrol Permeation through Sublingual Mucosa: Chemical Permeation Enhancers versus Spray Drying Technique to Obtain Fast-Disintegrating Sublingual Mini-Tablets.

Resveratrol (RSV) is a natural polyphenol with several interesting broad-spectrum pharmacological properties. However, it is characterized by poor oral bioavailability, extensive first-pass effect metabolism and low stability. Indeed, RSV could benefit from the advantage of the sublingual route of administration. In this view, RSV attitudes to crossing the porcine sublingual mucosa were evaluated and promoted both by six different chemical permeation enhancers (CPEs) as well as by preparing four innovative fast-disintegrating sublingual mini-tablets by spray drying followed by direct compression. Since RSV by itself exhibits a low permeation aptitude, this could be significantly enhanced by the use of CPEs as well as by embedding RSV in a spray-dried powder to be compressed in order to prepare fast-disintegrating mini-tablets. The most promising observed CPEs (menthol, lysine and urea) were then inserted into the most promising spray-dried excipients’ compositions (RSV-B and RSV-C), thus preparing CPE-loaded mini-tablets. However, this procedure leads to unsatisfactory results which preclude the possibility of merging the two proposed approaches. Finally, the best spray-dried composition (RSV-B) was further evaluated by SEM, FTIR, XRD and disintegration as well as dissolution behavior to prove its effectiveness as a sublingual fast-disintegrating formulation.

Comparing freeze drying and spray drying of interleukins using model protein CXCL8 and its variants

Spray-dried products, such as synthetic peptides and hormones, have already been approved by the U.S. Food and Drug Agency and the European Medicines Agency, while spray-dried antibodies or interleukins, are not yet available on the market. Concerning the latter group, knowledge on whether and how spray-drying (SD) can be performed without adversely affecting their biological activity is lacking. Accordingly, this study aimed at establishing a SD process (Büchi B-90 spray dryer) using three Interleukin-8 based proteins (7–74 kDa) that were dispersed in phosphate buffered saline to maintain their stability. A Box-Behnken Design of Experiments was conducted to identify the appropriate process parameters taking into account the thermal stability of interleukin-8. In parallel, a FD process was developed. Both powders were stored for up to 12 weeks. Powder characterization included residual moisture evaluation and the mean particle size of the SD powder was investigated with Laser Diffraction Analysis. The hydrodynamic volume was measured via size exclusion chromatography and sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The secondary structure of the model proteins in the solid state was assessed with Fourier-transformation infrared spectroscopy for detecting the protein folding patterns and reconstituted with Circular Dichroism Spectroscopy. Finally, the binding affinity was studied with Surface Plasmon Resonance and Isothermal Fluorescence Titration, the protein stability with Chaotropic Unfolding, and the activity studies were carried out with the chemotaxis assay. The results showed that SD and FD powders with a residual moisture of less than 5 wt% were obtained. The interleukins showed no unfolding upon processing, neither in solid state nor reconstituted. Oligomerization was observed for FD, but not for SD interleukins. However, the unfolding, binding affinity and activity of all interleukins examined did not decrease in neither SD nor FD powders, even after 12 weeks of storage. Thus, it can be concluded that SD of interleukin formulations at outlet temperatures close to ambient temperature is a promising process for transferring them into a stable powder.

Impact of temperature and relative humidity on physicochemical properties of the spray dried red flesh dragon fruit powder during storage

This study was carried out to evaluate the effects of storage temperature (5 - 7oC, 29 - 31oC, and 50oC) and relative humidity (RH 10 - 84%) on the stability of antioxidant compounds such as betacyanin, polyphenols. The changes in color, moisture content, the water activity of spray-dried red flesh dragon fruit powder during storage were also observed. The results showed that after 40 days of storage at 5 - 7oC, the samples got betacyanin content of 3.76 mg/100 g dw and a total phenolic of 28.31 mg/100 g dw. These values were higher than those of samples stored at ambient temperature (29 - 31oC) and 50oC. Besides, this study also recorded that the low relative humidity of the environment at 10 - 23% maintained the product's betacyanin (4.16 - 3.61 mg/100 g dw) and polyphenol content (27.29 - 25.66 mg/100 g dw) as well as a desirable water activity, which was better than the zone from 57% to 84% (0.28 - 0.3).

Determination of limiting factors in a novel superconcentration-granulation based dairy powder manufacturing process

An innovative approach based on superconcentration and granulation was investigated to manufacture dairy ingredients at lab-scale. A wet mass characterization technique, which measured agitator current consumption, was developed to study cohesiveness of super-concentrated products at various dry matter (DM) contents. For all ingredients, a composition-dependent cohesive phase was observed as DM increased, which was typified by a sharp rise and subsequent fall in power consumption. The effect of powder back-mixing on granulation was studied using three superconcentrate:powder (w/w) ratios (1:0.8, 1:1 and 1:1.2, respectively). Minimum powder addition rate for successful granulation was related to DM content at the end of the cohesive phase. Granulated powders had larger particle size, higher densities, lower porosities and enhanced flow properties compared to commercial spray-dried powders. The lab-scale model provided useful information on physical properties and limits during superconcentration and granulation, which increases the scientific knowledge relating to this novel powder production approach. Industrial relevanceSpray drying is the most widely utilized powder manufacturing technology in the dairy industry, especially for producing ingredients and nutritional products. It is, however, extremely energy intense and therefore spray drying of high-volume, low-value dairy streams such as permeate represents a poor use of resources for industry. An alternative spray dryer-free process has been developed for such streams, with significant savings. This process is based on superconcentration of streams to DM content in excess of what is typically seen in a spray-drying process (up to 80% w/w DM) followed by granulation achieved by back-mixing of finished product and, finally, drying of granules. However, little information is available on how various dairy ingredients behave in this system. Therefore, a novel lab-scale production model was produced to determine limits of superconcentration and granulation behavior of various ingredients. This work provides vital information and represents the first step in a larger program which will culminate in demonstration of the industrial applicability of the new approach for drying of various dairy streams.

Spray-Dried Quercetin-Lactose Powders for Oral Tablets with Improved Dissolution Rates and Modified Material Properties

This study is aimed at using spray drying method to codisperse it with the commonly used drug carrier lactose in different solvents and then pass it through a spray dryer to obtain different samples. The results showed that the dissolution rate and solubility of the samples obtained by dispersion in hot water and 25% ethanol were significantly higher. The water of crystallization peaks of the raw material disappeared at 105-125°C and 130-150°C (DSC). The excipient lactose had a small upward exothermic peak at 177°C and a significant heat absorption peak at 209°C before untreated (XRD). α-Lactose peaks were observed at 12.5°, 19.1°, 19.6°, and 19.9° at 2θ in both samples, and β-lactose peaks were found at 10.5° at 2θ in sample A, but not in sample B (FTIR). The complex sharp peaks of lactose at 1100 cm-1 and quercetin at 1700-1000 cm-1 became moderated (SEM). The sample obtained by spray drying has a slit-type mesoporous structure with an average pore size of about 9.3 nm.

Synthesis, Physicochemical Characterization, In Vitro 2D/3D Human Cell Culture, and In Vitro Aerosol Dispersion Performance of Advanced Spray Dried and Co-Spray Dried Angiotensin (1-7) Peptide and PNA5 with Trehalose as Microparticles/Nanoparticles for Targeted Respiratory Delivery as Dry Powder Inhalers.

The peptide hormone Angiotensin (1—7), Ang (1—7) or (Asp-Arg-Val-Tyr-Ile-His-Pro), is an essential component of the renin–angiotensin system (RAS) peripherally and is an agonist of the Mas receptor centrally. Activation of this receptor in the CNS stimulates various biological activities that make the Ang (1—7)/MAS axis a novel therapeutic approach for the treatment of many diseases. The related O-linked glycopeptide, Asp-Arg-Val-Tyr-Ile-His-Ser-(O-β-D-Glc)-amide (PNA5), is a biousian revision of the native peptide hormone Ang (1—7) and shows enhanced stability in vivo and greater levels of brain penetration. We have synthesized the native Ang (1—7) peptide and the glycopeptide, PNA5, and have formulated them for targeted respiratory delivery as inhalable dry powders. Solid phase peptide synthesis (SPPS) successfully produced Ang (1—7) and PNA5. Measurements of solubility and lipophilicity of raw Ang (1—7) and raw PNA5 using experimental and computational approaches confirmed that both the peptide and glycopeptide have high-water solubility and are amphipathic. Advanced organic solution spray drying was used to engineer the particles and produce spray-dried powders (SD) of both the peptide and the glycopeptide, as well as co-spray-dried powders (co-SD) with the non-reducing sugar and pharmaceutical excipient, trehalose. The native peptide, glycopeptide, SD, and co-SD powders were comprehensively characterized, and exhibited distinct glass transitions (Tg) consistent with the amorphous glassy state formation with Tgs that are compatible with use in vivo. The homogeneous particles displayed small sizes in the nanometer size range and low residual water content in the solid-state. Excellent aerosol dispersion performance with a human DPI device was demonstrated. In vitro human cell viability assays showed that Ang (1—7) and PNA5 are biocompatible and safe for different human respiratory and brain cells.

Tailored synbiotic powder (functional food) to prevent hyperphosphataemia (kidney disorder)

Hyperphosphataemia is treated with phosphate binders, which can cause adverse effects. Spray-dried synbiotic powder (SP) composed of Lactobacillus casei JCM1134 (a phosphate-accumulating organism; PAO) and Aloe vera is potentially a safer alternative for efficient phosphate removal. In this study, a novel strategy was developed; lysine-derivatized deacetylated A. vera (DAVK) was synthesised and fabricated on phosphate-deficient PAO (PDP) for efficient phosphate transfer and then spray-dried with the supernatant of DAV centrifugation to form a sacrificial layer on PDP for SP integrity during gastric passage. In vitro experiments revealed that PAO removed only 1.6% of the phosphate from synthetic media, whereas SP removed 89%, 87%, and 67% (w/v) of the phosphate from milk, soft drink, and synthetic media, respectively, confirming the protective role of A. vera and efficient phosphate transport. Compared with commercial binders, SP effectively removed phosphate from synthetic media, whereas SP and CaCO3 exhibited comparative results for milk and soft drink. Importantly, CaCO3 caused hypercalcaemia. Thus, the described SP presents a promising tool to prevent hyperphosphataemia. This study also revealed a novel factor: diets of patients with chronic kidney disease should be monitored to determine the optimal phosphate binders, as phosphate removal performance depends on the accessible phosphate forms.

(E)-Anethole microspheres as an alternative insecticide in funnel traps

Pyrethroids are the insecticides most commonly used inside traps, and the lack of alternatives poses the risk of pests developing resistance. In this paper we present two (E)-anethole formulations (spray drying (SD) and oil emulsion entrapment (OEE) processes) that provide a controlled release of their bioactive ingredient in the vapour phase with insecticidal potential in funnel traps.An experiment with the two pyralid moths Ephestia kuehniella Zeller and Plodia interpunctella Hübner was set up at two pilot stores in Spain for a four-month period. The microspheres (4 g of SD powder/trap or 6 g of OEE beads/trap) remained effective for 100 days, killing the moths by volatile activity. The efficacy values were within the interval of 70–100% for the first half of the experiment, with a decrease afterwards. The OEE beads performed better than did SD powder in the long run: over 80% efficacy for the whole experiment. The OEE process gives more loading capacity (19.7 g of (E)-anethole per 100 g of beads) and entrapment efficiency (28.6 g of (E)-anethole encapsulated per 100 g of (E)-anethole added) and is slower in releasing the product.In a laboratory study for E. kuehniella, the LC50 was 58.2 mg/L for SD after 24 h exposure to vapours and 111.6 mg/L for OEE after 48 h exposure to vapours. Therefore, the SD powder provides a quicker release of the bioactive ingredient.The results indicate that encapsulated (E)-anethole could be a promising insecticide for mass trapping, mating disruption and attract and kill strategies.

Spray drying preparation of polymethyl methacrylate-grafted natural rubber composite powders and its impact reinforcement effect

Encapsulation represents one feasible approach of preparing powdered natural rubber. Herein, we demonstrated the preparation of polymethyl methacrylate-grafted natural rubber (PMMA-g-NR) powders through emulsion polymerization followed by spray drying and investigated its impact reinforcement effect after blending with polylactic acid (PLA). The effects of feeding order, initiator concentration (CHPO/TEPA), monomer concentration (MMA) and reaction time on the grafting efficiency and yield were investigated. 1H-NMR and FTIR analyses confirmed the formation of PMMA-g-NR powder with high grafting efficiency (∼85%). TEM observations revealed the core-shell structure of the composite powder particles. DSC and TGA analyses proved that the PMMA-g-NR powder possessed improved thermal properties compared to neat NR. Impact strength of PLA/PMMA-g-NR blends were improved by 4.5-fold by the spray-dried composite powder prepared using 25 phr MMA and 1 phr CHPO/TEPA with 5 hours reaction time. The enhanced mechanical properties were attributed to the microstructures and high surface areas of PMMA-g-NR powder.

The Influence of Formulation Components and Environmental Humidity on Spray-Dried Phage Powders for Treatment of Respiratory Infections Caused by Acinetobacter baumannii.

The feasibility of using respirable bacteriophage (phage) powder to treat lung infections has been demonstrated in animal models and clinical studies. This work investigated the influence of formulation compositions and excipient concentrations on the aerosol performance and storage stability of phage powder. An anti-Acinetobacter baumannii phage vB_AbaM-IME-AB406 was incorporated into dry powders consisting of trehalose, mannitol and L-leucine for the first time. The phage stability upon the spray-drying process, room temperature storage and powder dispersion under different humidity conditions were assessed. In general, powders prepared with higher mannitol content (40% of the total solids) showed a lower degree of particle merging and no sense of stickiness during sample handling. These formulations also provided better storage stability of phage with no further titer loss after 1 month and <1 log titer loss in 6 months at high excipient concentration. Mannitol improved the dispersibility of phage powders, but the in vitro lung dose dropped sharply after exposure to high-humidity condition (65% RH) for formulations with 20% mannitol. While previously collected knowledge on phage powder preparation could be largely extended to formulate A. baumannii phage into inhalable dry powders, the environmental humidity may have great impacts on the stability and dispersion of phage; therefore, specific attention is required when optimizing phage powder formulations for global distribution.

Particle surface design for enhanced reconstitution of fat-based food powders

Spray-dried milk powders are characterized by an underrepresentation of hydrophilic compounds on the particle surface compared to the bulk, which renders reconstitution unfavourable. To overcome this issue, in the present study we instigated the coating of whole milk powder with two types of micronized lactose: crystalline and amorphous.We demonstrate that deposition of micronized lactose on the surface of whole milk powder leads to an increase in the reconstitution rate at 21 °C, correlated with a decrease in the apparent contact angle of the material. We also show that the physical solid state of micronized lactose is an important factor influencing the reconstitution performance of coated whole milk powder; If micronized lactose is amorphous, increasing the coating concentration beyond a certain point has little or no further effect on the reconstitution kinetics, which could be explained by viscosity build-up effects that hamper capillary penetration and sinking.

Active packaging for postharvest storage of cherry tomatoes: Different strategies for application of microencapsulated essential oil

Pink pepper essential oil was microencapsulated in single-layer (protein stabilized) and double-layer (protein-polysaccharide stabilized) emulsions, which were applied in poly(ethylene terephthalate) boxes for storage of cherry tomatoes (Solanum lycopersicum var. cerasiforme) following two different strategies: a thin coating formed after emulsion drying directly on the box lid, or a sachet containing spray-dried emulsion powder attached to the box lid. Fruits were stored in for 21 days at 25 °C. Packaging without essential oil was used as a control. Active packaging resulted in lower weight loss, total soluble solids, pH and lycopene concentration, while fruits stored in non-active packaging showed evidence of faster ripening based on these parameters. The greater release of volatiles from coatings (≈ 90 %) compared to spray-dried powder (76.9–86.9 %) suggests that this approach was a more advantageous strategy to maintain the fruit quality (p < 0.05). Both approaches showed potential for post-harvest storage of fresh fruit.

Current knowledge about physical properties of innovative probiotic spray-dried powders produced with lactose-free milk and prebiotics

Lactose-free probiotic powders were obtained by mixing Bifidobacterium BB-12 suspensions with lactose-free milk powder or lactose-free milk powder and prebiotics (inulin or oligofructose). A thorough investigation was performed to know their water sorption properties and physical and thermal characteristics. By evaluating the water sorption properties, the Peleg model fitted well to the experimental sorption data, showing that the equilibrium moisture content of powders increased as the relative humidity increased. The isotherm found for all samples was a Type III Isotherm, commonly observed in most foods. For both morphology and particle size, the use of different carrier agents affected these properties; however, all the spray-dried powders presented good size to be added in food products. X-ray diffraction and Raman spectroscopy showed us amorphous structure for all powders, and typical bands of the milk constituents and sugars, respectively. Regarding the spray-dried powders thermal properties, it was possible to confirm that the addition of prebiotics gave higher thermal stability, highlighting the sample produced with inulin. We concluded that a good quality of lactose-free milk based probiotic powder could be obtained using spray drying technique, with great potential to be applied in lactose-free dairy products.

Evaluation of the stability of a spray-dried tuberculosis vaccine candidate designed for dry powder respiratory delivery

Particle engineering via spray drying was used to develop a dry powder presentation of an adjuvanted tuberculosis vaccine candidate. This presentation utilizing a trileucine-trehalose excipient system was designed to be both thermostable and suitable for respiratory delivery. The stability of the spray-dried vaccine powder was assessed over one year at various storage temperatures (-20, 5, 25, 40, 50 °C) in terms of powder stability, adjuvant stability, and antigen stability. A formulation without trileucine was included as a control. The results showed that the interior particle structure and exterior particle morphology of the powder was maintained for one year at 40 °C, while the control case exhibited a small extent of particle fusing under the same storage conditions. Moisture content was maintained, and powder solid state remained amorphous for all storage temperatures. Aerosol performance was assessed with a commercial dry powder inhaler in combination with a human mouth-throat model. The emitted dose and lung dose were maintained for all samples after one year at temperatures up to 40 °C. Nanoemulsion size and oil content of the adjuvant system were maintained after one year at temperatures up to 40 °C, and the agonist content was maintained after one year at temperatures up to 25 °C. The antigen was completely degraded in the control formulation at seven months of storage at 40 °C; by contrast, 45% of the antigen was still present in the trehalose-trileucine formulation after one year of storage at 50 °C. Comparatively, the antigen was completely degraded in a liquid sample of the vaccine candidate after only one month of storage at 37 °C. The spray-dried trehalose-trileucine vaccine powder clearly maintained its inhalable properties after one year’s storage at high temperatures and improved overall thermostability of the vaccine.

Fluidized-Bed Granulation of Probiotics-Encapsulated Spray-Dried Skim Milk Powder: Effects of a Fluidizing Aid, Moisture-Activation and Dehydration.

A probiotic powder of poor flowability with high dust content, prepared by spray drying reconstituted skim milk fermented with Lactobacillus rhamnosus GG (LGG), was granulated by fluidized-bed granulation (FBG). The effects of the addition of skim milk powder (SMP) as a fluidizing aid, and of simple moisture-activation with or without dehydration, were investigated with respect to the performance of the FBG process. A fine, poorly fluidizable LGG powder (Geldart Group C) could be fluidized and granulated, with a 4- to 5-fold increase in particle size (d4,3 = 96–141 μm), by mixing with SMP (30–50%), which has larger, fluidizable particles belonging to Geldart Group A. Moisture-activation after the mixing, followed by fluidized-bed dehydration with hot air to remove excess moisture, further improved the FBG; the yield of the granules increased from 42% to 61% and the particle size distribution became much narrower, although the average particle size remained almost the same (d4,3 = 142 μm). These granules showed a popcorn-type structure in scanning electron microscopy images and encapsulated a sufficient level of viable LGG cells (1.6 × 108 CFU g−1). These granules also exhibited much better flowability and dispersibility than the spray-dried LGG powder.

Effects of orally administered Euglena gracilis and its reserve polysaccharide, paramylon, on gastric dysplasia in A4gnt knockout mice

Euglena gracilis is widely utilized as food or supplement to promote human and animal health, as it contains rich nutrients. In this study, we administered spray-dried powder of E. gracilis and paramylon, β-glucan stored in E. gracilis cells, to A4gnt knockout (KO) mice. A4gnt KO mice are a mutant mouse model that spontaneously develops gastric cancer through hyperplasia-dysplasia-adenocarcinoma sequence in the antrum of the stomach, and we observed the effects of E. gracilis and paramylon on the early involvements of A4gnt KO mice. Male and female 10-week-old A4gnt KO mice and their age-matched wildtype C57BL/6J mice were orally administered with 50 mg of E. gracilis or paramylon suspended in saline or saline as a control. After 3-week administration, animals were euthanatized and the stomach was examined histopathologically and immunohistochemically. Gene expression patterns of the stomach, which have been reported to be altered with A4gnt KO, and IgA concentration in small intestine were also analyzed with real-time PCR and ELISA, respectively. Administration of Euglena significantly reduced the number of stimulated CD3-positive T-lymphocytes in pyloric mucosa of A4gnt KO mice and tend to reduce polymorphonuclear leukocytes infiltration. Euglena administration further downregulated the expression of Il11 and Cxcl1 of A4gnt KO mice. Euglena administration also affected IgA concentration in small intestinal contents of A4gnt KO mice. Paramylon administration reduced the number of CD3-positive lymphocytes in pyloric mucosa of A4gnt KO mice, and downregulated the expressions of Il11 and Ccl2 of A4gnt KO mice. Although we found no significant effects on gross and microscopic signs of gastric dysplasia and cell proliferation, the present study suggests that the administration of Euglena and paramylon may ameliorate the early involvements of A4gnt mice through the effects on inflammatory reactions in the gastric mucosa. The cancer-preventing effects should be studied with long-term experiments until actual gastric cancer formation.

Optimizing viability and yield and improving stability of Gram-negative, non-spore forming plant-beneficial bacteria encapsulated by spray-drying.

This study investigates methods to commercialize safer alternatives to chemical pesticides that pose risks to human safety and the environment. Spray-drying encapsulation of the plant-protective, antifungal bacterium Collimonas arenae Cal35 in in situ cross-linked alginate microcapsules (CLAMs) was optimized to minimize losses during spray-drying and maximize yield of spray-dried powder. Only inlet temperature significantly affected survival during spray-drying, while inlet temperature, spray rate, and alginate concentration significantly affected yield of spray-dried powder. Lowering inlet temperature to 95°C provided the greatest survival during spray-drying, while increasing inlet temperature and lowering spray rate and alginate concentration produced the highest yield. Without the CLAMs formulation, Cal35 did not survive spray-drying. When Cal35 was encapsulated in CLAMs in the presence of modified starch, shelf survival was extended to 3 weeks in a low oxygen, low humidity storage environment. Cal35 retained its antifungal activity throughout spray-drying and shelf storage, supporting its potential use as a formulated biofungicide product.

Impact of the whey protein/casein ratio on the reconstitution and flow properties of spray-dried dairy protein powders

This study focuses on the impact of the whey protein/casein ratio (100/0, 79/21, 57/43, 35/65, and 12/88) on the physicochemical and functional characteristics of dairy protein powders. Spray-drying was performed in the following conditions: 200 °C inlet air temperature and 85 °C outlet air temperature. Physicochemical properties (particle size distribution, shape factors, moisture content, and water activity) of spray-dried powders were characterized to explain their reconstitutability, on the basis of the wettability, dispersibility, solubility indices, and their flowability, evaluated with the FT4 powder rheometer.Reconstitutability analyses revealed that solubility of dairy protein powders linearly varied with the whey protein/casein ratio. It was also highlighted that wettability and dispersibility determined with the standard methods were not relevant to evaluate the reconstitutability of investigated powders: in fact, all studied powders were non-wettable and non-dispersible according to the milk powder standards. This was likely to result from the low median particle size (between 10 and 30 μm) of powders produced by spray-drying at pilot-scale.The flowability of powders was evaluated as poor due to a high level of interparticular cohesion, which mainly derived from their small median particle size. The impact of protein composition on flowability was not statistically significant, despite a shape modification reflected by a decrease in particle sphericity upon casein proportion increase. The small particle size, leading to poor flow properties, overwhelmed the impact the whey protein/casein ratio, but a slight improvement of the flowability and a reduction of cohesion was induced by higher proportions of whey proteins.