Spray Drying Process Parameters Research Articles

Safflower protein as a potential plant protein powder: optimization of extraction and spray-drying process parameters and determination of physicochemical and functional properties.

The research about sustainable and alternative plant protein sources has accelerated with the increasing need for protein. Safflower meal has a potential to be used in protein production due to its high protein content. This research aimed to produce an alternative plant-based protein powder using safflower meal. Both extraction and spray-drying parameters of safflower protein powder production were optimized using response surface methodology to achieve maximum yield. Moreover, the physicochemical and functional properties of safflower protein were determined and compared with those of commercial protein powders (soy, sunflower, pea, fava bean, and rice). The optimum extraction conditions were found to be 33.06:1 mL-1 g solvent-to-meal ratio, pH 11.00, 23.34 °C extraction temperature, and 30.86 min extraction time, which were achieved with a protein yield response of 75.21%. The highest powder yield (51.28%) was recorded for drying conditions of inlet air temperature of 160.11 °C, aspiration rate of 54.17 m3 h-1, and feed flow rate of 16.01 mL min-1. According to the amino acid profile of safflower protein, the glutamic acid content (14 475 mg (100 g)-1) was highest, while the methionine content (96 mg (100 g)-1) was lowest. Moreover, safflower protein can be regarded as a high-quality protein due to its high essential amino acid ratio (41.55%). The experiments showed that safflower protein had high solubility and good foam and emulsifying properties. Safflower protein could be a nutritional and functional protein source for the food industry. © 2024 Society of Chemical Industry.

Comparison of conventional and supercritical CO2 extraction techniques of Curcuma longa L. oleoresin and optimization of the spray drying process

Turmeric (Curcuma longa) is used as fresh turmeric and flour in Loreto, Peru. However, there are still no studies on the characterization and utilization of oleoresin as an input for the food industry. The objectives of this study were to compare conventional and supercritical CO2 extraction techniques of turmeric oleoresin and optimize the microencapsulation process through spray drying. Yield, curcuminoid content, total phenolic content (TPC), and antioxidant capacity (AC) of oleoresins obtained with supercritical CO2 and conventional extraction techniques were compared. Spray drying process parameters for microencapsulation of oleoresin were optimized. The highest extraction yield of oleoresin was obtained with ethanol and methanol. However, these extracts had low values of total curcuminoids of 25.81% and 29.31%, respectively. Oleoresins extracted with supercritical CO2 (SC-CO2), ethanol, and acetone showed high contents of TPC with 0.2697, 0.2602, and 0.2560 g GAE/g oleoresin, respectively, while oleoresin extracted with SC-CO2 had the highest AC by ABTS (2491.96 µmol TE/g oleoresin). Optimum conditions of spray drying were obtained with 190°C and a feed flow of 3.3 mL/min. In conclusion, Curcuma longa oleoresin is a valuable nutritional source for potential use in the food industry.

Optimization of Spray Drying Process Parameters for the Production of Cranberry Flavoured Oat Milk Powder Using Response Surface Methodology

Optimization of Spray Drying Process Parameters for the Production of Cranberry Flavoured Oat Milk Powder Using Response Surface Methodology

Modeling and optimization of spray drying process parameters using artificial neural network and genetic algorithm for the production of probiotic (Lactiplantibacillus plantarum) finger millet milk powder

AbstractConsumers have been more inclined towards functional food due to various health issues. Non‐dairy‐based probiotic milk could be the potential alternative to fulfill consumer demand. Spray drying of functional health drinks could enhance the shelf life and reduce the transportation cost of developed food powder. The current study was focused on the modeling and optimization of spray‐drying process parameters using an artificial neural network (ANN) coupled with a genetic algorithm (GA). The data so obtained using ANN‐GA was also compared with the data obtained using response surface methodology (RSM) coupled with desirability function (DF). The results indicated that the ANN model was better at predicting the response parameters compared to the RSM model with a higher correlation coefficient (R) of .9997, .9994, .9964, and .9992 for training, testing, validation, and all datasets, respectively. The optimum conditions obtained using RSM‐DF were 160.41°C of inlet air temperature, 33.77% of maltodextrin content, and 138.79 mL/h of feed rate while that for ANN‐GA were 160.87°C, 20%, and 200 mL/h. The RSM‐DF method proved to be better for the optimization of response parameters. Therefore method selection for modeling and optimization of process and response parameters must be based on fulfilling the specific criteria.Practical ApplicationsNon‐dairy milk production has gained popularity in the area of research and product development. Various process protocols have been reported to produce high‐quality non‐dairy milk to fulfill the demand for a vegan diet. However, nutrient bioavailability, longer shelf life, product stability, and consumer acceptability are hard to obtain from cereal‐based non‐dairy milk. The current study contributes to produce spray‐dried milk powder followed by fermentation at optimum drying conditions with good quality and stability. The process has been modeled and optimized in the study using advanced statistical tools such as ANN‐GA and RSM‐DF. They can effectively predict the quality parameters and determine the optimal conditions for new experimental data.

Optimization of spray-drying process parameters for microencapsulation of three probiotic lactic acid bacteria selected by their high viability rate in sucrose and fructose levels and high temperatures

Optimization of spray-drying process parameters for microencapsulation of three probiotic lactic acid bacteria selected by their high viability rate in sucrose and fructose levels and high temperatures

Optimization of Spray Drying Process Parameters for the Preparation of Inhalable Mannitol-Based Microparticles Using a Box-Behnken Experimental Design.

Inhalation is used for local therapy of the lungs and as an alternative route for systemic drug delivery. Modern powder inhalation systems try to target the required site of action/absorption in the respiratory tract. Large porous particles (LPPs) with a size >5 μm and a low mass density (usually measured as bulk or tapped) of <0.4 g/cm3 can avoid protective lung mechanisms. Their suitable aerodynamic properties make them perspective formulations for deep lung deposition. This experiment studied the effect of spray-drying process parameters on LPP properties. An experimental design of twelve experiments with a central point was realized using the Box-Behnken method. Three process parameters (drying temperature, pump speed, and air speed) were combined on three levels. Particles were formed from a D-mannitol solution, representing a perspective material for lung microparticles. The microparticles were characterized in terms of physical size (laser diffraction), aerodynamic diameter (aerodynamic particle sizer), morphology (SEM), and densities. The novelty and main goal of this research were to describe how the complex parameters of the spray-drying process affect the properties of mannitol LPPs. New findings can provide valuable data to other researchers, leading to the easy tuning of the properties of spray-dried particles by changing the process setup.

Spray-Dried Inhalable Powder Formulations of Gentamicin Designed for Pneumonic Plague Therapy in a Mouse Model.

Infection with Yersinia pestis (Y. pestis) may cause pneumonic plague, which is inevitably fatal without treatment. Gentamicin (GM), an aminoglycoside antibiotic, is a drug commonly used in the treatment of plague. However, it requires repeated intramuscular or intravenous administration. Pulmonary drug delivery is noninvasive, with the advantages of local targeting and reduced risk of systemic toxicity. In this study, GM powders were prepared using spray-drying technology. The powders displayed good physical and chemical properties and met the requirements for human pulmonary inhalation. The formulation of the powders was optimized using a 32 full factorial design. A formulation of 15% (w/w) of L-leucine was prepared, and the spray-drying process parameters using an inlet temperature of 120°C and a 15% pump rate were determined to produce the best powder. In addition, the optimized GM spray-dried powders were characterized in terms of morphology, crystallinity, powder fluidity, and aerodynamic particle size distribution analysis. In a mouse model of pneumonic plague, we compared the therapeutic effects among three administration routes, including subcutaneous injection, liquid atomization, and dry powder atomization. In conclusion, our data suggest that inhalation therapy with GM spray-dried powders is an effective treatment for pneumonic plague.

Process Modelling, Scale-Up and Characterization of Acetaminophen Spray Dried Milk Powder as Novel Pediatric Dosage Form.

Successful drug therapy in children is contingent upon hassle-free administration of pediatric dosage forms. Pediatric patients suffer from difficulty in swallowing due to weak esophagus muscles in their early age. Considering this challenge liquid formulations are preferred over solid dosage form among pediatric patients to avoid the possibility of choking which can be a serious life-threatening condition in children. The main aim of the present research work was to develop a reconstitutable amorphous acetaminophen spray-dried milk powder (ASDM) as novel pediatric formulation. ASDM was prepared by spray drying process and the spray drying process was optimized using Box-Behnken design to study the effect of spray drying process parameters at X1 [inlet temperature], X2 [aspiration rate] and X3 [feed rate] to Y1 [% yield], Y2 [angle of repose], Y3 [Hausner's Ratio] and Y4 [Carr's Index] as dependent variables of ASDM. In addition, each batch was characterized for particle size by polarized light microscopy and drug entrapment. Predicted parameters from optimized spray drying process model were successfully employed to manufacture a scale up cum validation batch of ASDM, which showed notably improved yield and desirable flow properties. The scale-up validation batch was further characterized using thermal analysis, diffraction studies, spectroscopic analysis, dispersion studies, stability APAP in dispersion formulation and formulation stability studies to confirm the physico-chemical stability of ASDM. Thus, ASDM for oral use can serve as a promising pediatric formulation and the developed prototype formulation can be further extended to future newly discovered drugs with similar characteristics.

Effect of varied spray drying parameters on physicochemical, micrometric and microstructural characteristics of pear powder employing response surface approach

PurposeCurrently, there is a great demand for those food products that are easy to prepare or ready for direct consumption. Making pear fruit/juice available round the year is desirous owing to pears' high-nutritional value and specific pleasant taste. Pear is, however, a seasonal fruit and under ambient conditions has a limited shelf life rendering it available as fresh fruit for a specific period.Design/methodology/approachThe study aimed to optimize the spray drying process parameters using response surface methodology for the development of pear juice powder. The process variables included the inlet air temperature of 140–210°C, maltodextrin levels of 4–25%, atomization speed of 11,400–28,000 rpm, feed flow rate of 180–630 mL/hr, and feed total soluble solids (TSS) of 13–30°Brix. The dependent responses were powder yield, solubility, antioxidant activity {% 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity}, dispersibility, hygroscopicity and particle density.FindingsAmong independent variables, inlet air temperature showed a predominant effect. The optimum processing conditions for the development of pear juice powder with optimum quality were 163.02°C inlet air temperature, 13.50% maltodextrin, 28,000 rpm atomization speed, 390.94 mL/h feed flow rate, and 25.5°Brix feed TSS. Under these optimum conditions, pear powder with desirable properties could be produced. The experimental and predicted values were found to be in agreement, indicating the suitability of the model in predicting optimizing responses of pear powder. Glass transition temperature of pear powder was found to be 36.60 ± 0.40°C, which is much higher than that of ambient temperature, suggesting better shelf stability.Originality/valueThe processing of pear fruit has resulted in the increased demand for pear juice powder in both domestic and international markets as a primer of new food products. The optimum conditions obtained in the current study could provide a new insight to the food industry in developing spray-dried pear powder of optimum quality. This can open up a new horizon in the field of food industry for the common masses of Jammu and Kashmir, India.

Effect of the modification of spray drying parameters on the fabrication of bovine-derived hydroxyapatite microspheres for biomedical applications

In this work, the effect of the spray dryer parameters on bovine-derived hydroxyapatite (BHAp) was studied to fabricate microspheres with controlled particle size distribution and morphology. A factorial design was implemented to establish the impact of spray drying process parameters on the final BHAp powder properties. The critical process factors were solid content in the slurry, atomization pressure, and hot air flow rate, whereas the studied experimental outputs were particle size distribution and morphology, characterized by laser diffraction and scanning electron microscopy, respectively. Additionally, the Ca/P molar ratio was evaluated from X-ray diffraction data. The obtained results showed a strong influence of the atomization pressure and the solid slurry content on the particle size distribution (increasing from 2.56 ± 0.02 µm to 32.46 ± 0.78 µm) and particle morphology (with an increased circularity from 0.3502 ± 0.0172 to 0.8688 ± 0.0039), being both properties suitable for thermal spray (TS) applications. Moreover, the BHAp crystalline structure and Ca/P molar ratio did not present any changes with the spray drying process parameters employed. Finally, it was found that magnesium was preserved in the spray dried particles, the former being also present in the starting powder feedstock.

Optimisation of spray drying process parameters of curcumin nanosuspension

The aim of this study was to optimise spray drying process parameters of curcumin nanosuspension. Method: an I-Optimal experimental model was designed by Design Expert software including 22 experiments. The independent variables were inlet temperature (oC), pump speed (ml/minute) and weight ratio of curcumin-loaded nanoparticles and carrier and nanoparticle; the dependent variables were particle size after redispersing (nm), polydispersity index, dispersion time (second) and spray drying yield. After the optimal parameters had been verified by experiments, some quality requirements of spray-dried powders were evaluated. Then the physical and chemical properties of curcumin in spray-dried powders were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and fourier-transform infrared spectroscopy (FT-IR). Results: the optimal parameters were established with the inlet temperature of 140oC, the pump speed of 5 ml/minute, the weight ratio of carrier and nanoparticle of 2:1. The obtained results of verification experiments were highly repeatable and were similar to the predicted ones from the software. The comparison of XRD spectra between curcumin crystal and spray-dried powders showed that curcumin in spray-dried powders existed in amorphous form. Furthermore, DSC patterns and FT-IR spectra of curcumin crystal and spray-dried powder demonstrated that there were interactions among curcumin, chitosan and lipoid S100. Conclusion: nano curcumin powders have met the quality requirements of preparation in laboratory-scale. This is a platform for further research later and eventually put into industrial-scale production.

Gaining Insight into the Role of the Solvent during Spray Drying of Amorphous Solid Dispersions by Studying Evaporation Kinetics.

Spray drying is one of the most commonly used manufacturing techniques for amorphous solid dispersions (ASDs). During spray drying, very fast solvent evaporation is enabled by the generation of small droplets and exposure of these droplets to a heated drying gas. This fast solvent evaporation leads to an increased viscosity that enables kinetic trapping of an active pharmaceutical ingredient (API) in a polymer matrix, which is favorable for the formulation of supersaturated, kinetically stabilized ASDs. In this work, the relation between the solvent evaporation rate and the kinetic stabilization of highly drug-loaded ASDs was investigated. Accordingly, thermal gravimetric analysis (TGA) was employed to study the evaporation kinetics of seven organic solvents and the influence of solutes, i.e., poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA), fenofibrate (FNB), and naproxen (NAP), on the evaporation behavior. At 10 °C below the boiling point of the respective solvent, methanol (MeOH) had the lowest evaporation rate and dichloromethane (DCM) had the highest. PVPVA decreased the evaporation rate for all solvents, yet this effect was more pronounced for the relatively faster evaporating solvents. The APIs had opposite effects on the evaporation process: FNB increased the evaporation rate, while NAP decreased it. The latter might indicate the presence of interactions between NAP and the solvent or NAP and PVPVA, which was further investigated using Fourier transform-InfraRed (FT-IR) spectroscopy. Based on these findings, spray drying process parameters were adapted to alter the evaporation rate. Increasing the evaporation rate of MeOH and DCM enabled the kinetic stabilization of higher drug loadings of FNB, while the opposite trend was observed for ASDs of NAP. Even when higher drug loadings could be kinetically stabilized by adapting the process parameters, the improvement was limited, demonstrating that the phase behavior of these ASDs of FNB and NAP immediately after preparation was predominantly determined by the API-polymer-solvent combination rather than the process parameters applied.

Optimization of Spray-Drying Process Parameters to Study Anti-Sticking Effect of Hydroxypropyl Methyl Cellulose-VLV on Corni fructus Extracts.

To prevent the sticking of Corni fructus extract (CFE) during spray drying, the anti-sticking effects of different excipients were compared. Hydroxypropyl methylcellulose (HPMC)-VLV showed a higher powder yield at a lower dosage (8% of total solids), and a lower solution viscosity, compared with HPMC-E5. Therefore, HPMC-VLV is a more effective excipient for reducing CFE sticking during spray drying. The spray-drying process parameters were optimized by central composite rotatable design/response surface methodology, and spray drying was conducted under the following conditions: Inlet air temperature, 126 °C; atomization pressure, 1.05 bar; pump speed, 7.7 mL/min. Scanning electron microscopy showed that the powder comprised shrunken spherical particles with particle sizes in the range of 2-30 μm. Analysis of dynamic surface tension and chemical elements on the powder surface showed that HPMC-VLV rapidly moved to the droplet surface owing to its surface activity. HPMC covered the droplet surface and reduced surface tension, achieving an anti-sticking effect. In conclusion, HPMC-VLV at a solid content of 8% significantly improved the spray drying and reduced sticking of CFE. The spray-drying process parameters were nonlinearly related to the dry product yield. Graphical Abstract.

Study on the optimization of spray drying process for Areca taro powder with microcystalline cellulose

Starch is a product of intensive processing of agricultural products. During the processing of plant starch, nutrients such as protein, dietary fiber, and minerals are removed. In addition to nutritional imbalance, rich nutrients have an impact on the environment. The object of research is Areca taro, a starch-rich agricultural product. The research aims to use spray drying technology to obtain a whole betel nut taro powder for food processing, such as sausages and noodles. The taro is used as a raw material, and the whole taro flour is obtained after peeling, cutting, crushing with water, and spray drying. Using single factor and orthogonal experiment to optimize the spray drying process parameters and embedding agent of taro powder, and then analyze its physical and chemical properties. The results show that adding 0.01 % Xanthan gum+0.12 % Microcrystalline cellulose (embedded agent) to the taro emulsion can increase the extraction rate of taro flour, speed up the drying speed, and prevent sticking to the wall. The best process of spray drying: the speed of atomizer was 16000 r/m, the wind temperature was 200 °C, the material liquid concentration was 28.00 % and the feeding rate was 75 mL/min. The taro powder produced by this process has better liquidity, light purple color, smooth texture, and strong flavor of taro. Product parameters: powder fluidity was 13.9 cm, extraction rate was 15.36 %, water activity was 0.416, chromaticity parameters were 19.73 (L* value), 2.96 (a* value) and 3.25 (b* value), bulk density was 0.44 g/mL. This technology can provide data support and reference for food processing companies. The taro whole powder would be widely used as food ingredients in future.

Surface fat and insolubility of whole camel milk powders as affected by spray drying operating parameters

Face centered central composite design was used to investigate the effect of spray drying process parameters (inlet temperature, atomization pressure and feed flow rate) on selected quality parameters of whole camel milk. During storage by freezing, the integrity of camel milk fat globules is maintained with observed aggregation. Whole camel milk contains 12.18% total solids, 3.5% protein and 3.99% [w/w] lactose whereas for the powders, the total solids content was in the range of 94–97%, protein 22–29% and lactose 27–31% [w/w]. By combining response surface methodology with desirability function, the spray drying process of whole camel milk was optimized with objectives of maximizing the yield and minimizing undesired quality degradation parameters. Consequently, it was possible to recover 62% of total solids without affecting the desired aspects of the final physico-chemical properties of powders (minimum insolubility index of 0.1 mL and surface fat content of 4.2% [w/w]) with targeted final moisture content of 4.5% [w/w]. These properties would make the powders safe during extended period of storage.

Physico-Chemical and In Vitro Characterization of Chitosan-Based Microspheres Intended for Nasal Administration.

The absorption of non-steroidal anti-inflammatory drugs (NSAIDs) through the nasal epithelium offers an innovative opportunity in the field of pain therapy. Thanks to the bonding of chitosan to the nasal mucosa and its permeability-enhancing effect, it is an excellent choice to formulate microspheres for the increase of drug bioavailability. The aim of our work includes the preparation of spray-dried cross-linked and non-cross-linked chitosan-based drug delivery systems for intranasal application, the optimization of spray-drying process parameters (inlet air temperature, pump rate), and the composition of samples. Cross-linked products were prepared by using different amounts of sodium tripolyphosphate. On top of these, the micrometric properties, the structural characteristics, the in vitro drug release, and the in vitro permeability of the products were studied. Spray-drying resulted in micronized chitosan particles (2–4 μm) regardless of the process parameters. The meloxicam (MEL)-containing microspheres showed nearly spherical habit, while MEL was present in a molecularly dispersed state. The highest dissolved (>90%) and permeated (~45 µg/cm2) MEL amount was detected from the non-cross-linked sample. Our results indicate that spray-dried MEL-containing chitosan microparticles may be recommended for the development of a novel drug delivery system to decrease acute pain or enhance analgesia by intranasal application.

Engineering Advances in Spray Drying for Pharmaceuticals.

Spray drying is a versatile technology that has been applied widely in the chemical, food, and, most recently, pharmaceutical industries. This review focuses on engineering advances and the most significant applications of spray drying for pharmaceuticals. An in-depth view of the process and its use is provided for amorphous solid dispersions, a major, growing drug-delivery approach. Enhanced understanding of the relationship of spray-drying process parameters to final product quality attributes has made robust product development possible to address a wide range of pharmaceutical problem statements. Formulation and process optimization have leveraged the knowledge gained as the technology has matured, enabling improved process development from early feasibility screening through commercial applications. Spray drying's use for approved small-molecule oral products is highlighted, as are emerging applications specific to delivery of biologics and non-oral delivery of dry powders. Based on the changing landscape of the industry, significant future opportunities exist for pharmaceutical spray drying.

Spray drying absorption for desulphurization: a review of recent developments

Sulphur dioxide (SO2) abatement technologies, i.e. flue gas desulphurization (FGD), have proven effective in curtailing the harmful SO2 emissions resulting from coal combustion for electrical power generation. New regulations on these emissions now require some power utilities to retrofit new FGD units to existing coal-fired power plants to meet required emission standards. Wet FGD limestone scrubbing has been predominantly used over other competing technologies. However, the simplicity of the spray-drying absorption (SDA) technology has made it an attractive alternative to the wet scrubbing process. SDA offers huge savings on energy, water, operating cost and maintenance. Despite high cost of the sorbent (hydrated lime) used, recent advances in SDA process offer considerable economic and technical advantages ranging from improved sorbent utilization, better atomization and enhanced performance. Alternative sorbents and additives are continuously being explored for simultaneous removal of pollutant gases from flue gas. The performance improvement areas in a lime spray drying system include the use of inorganic salt additives, recycling of the dried product and the use of siliceous materials. This study is intended to review FGD systems applicable to coal-fired power plants, through a technical comparison between competing technologies. Additionally, a review of the spray-drying absorption process and operating parameters affecting their efficiency was carried out, together with a critical assessment of the literature published to date.

Insolubility and denaturation of whey proteins of skimmed camel milk as affected by spray drying operating parameters

ABSTRACT The effect of spray drying process parameters (i.e., inlet temperature, atomization pressure, and feed flow rate) on the denaturation of whey proteins of skimmed camel milk was studied using a face-centered central composite design. Spray drying of skimmed camel milk (i.e., total solids of 8.4% [w/w]) produced powders with a total solids content of 94–97% (w/w), protein 22–29% (w/w) and lactose 27–31% (w/w). The process was optimized using response surface methodology in combination with desirability function. A maximum recovery of 61% of the total solids was achieved while still maintaining denaturation of whey protein and insolubility index levels at their minimum possible value of 39% and 0.1 mL, respectively. The final moisture content of the powder at these conditions was 3.3% (w/w). This implies that, as denaturation was the primary mechanism by which camel milk lose its protective proteins, minimizing denaturation would make it possible to produce skimmed camel milk powders with good nutritional and therapeutic values. The morphology of spray-dried skimmed camel milk processed at 140°C showed greater spherical intact particles than their cow milk powder counterparts.

Effect of spray drying process parameters on Uncaria tomentosa (Willd. ex Schult.) DC. dried extracts

Uncaria tomentosa (Willd. ex Schult.) DC. (Cat's claw) is a plant member of the Rubiaceae family, from the Amazon region, and used in traditional medicine as raw material for phytomedicines indicated for arthritis and osteoarthritis. This study aimed to evaluate the spray drying process parameters on the properties of different extracts obtained from Uncaria tomentosa. A reduced 24-1 multifactorial design was applied to evaluate the importance of the equipment variables (pump speed, spray nozzle diameter, air inlet temperature, and atomization airflow rate) in the process. Maltodextrin and acacia gum were used as carriers in a 1:1 (m/m) ratio, considering the solid residue content of the liquid plant extract. Process yield, moisture, and hygroscopicity were evaluated as dependent variables. Higher atomization airflow rate led to higher process yield for powdered dried extracts with maltodextrin. Higher temperature led to lower moisture contents regarding powdered dried extracts with acacia gum. No variable, for any carrier, was considered significant for hygroscopicity. The best spray drying configuration for the desired characteristics (i.e. lower hygroscopicity and moisture) used the larger spray nozzle with a diameter of 1.2 mm and the higher temperature of 150 °C, with both carriers.