Drying Process Variables Research Articles

Influence of drying process variables on the wet tensile strength of towel paper with the addition of polyamidoamine-epichlorohydrin (PAE) polymer

The tensile strength of paper towels with the addition of polyamidoamine-epichlorohydrin (PAE) polymer was tested. The papers were formed from a pulp consisting of pine and eucalyptus fibres in a 50/50 ratio. PAE was added to the paper pulp in an amount of 3.5 mg/g. The samples were pressed on a conventional press and dried on a drying cylinder. During the drying of the samples, the process parameters were changed, i.e., temperature (100 to 200 °C) and drying time (2 to 15 s). The drying conditions of the papers with the addition of PAE had a significant impact on the wet strength of the paper. The highest ratio of wet tensile index of the papers to dry tensile index in both directions, (MD and CD), was obtained for papers dried at 150 °C for 15 s. The results showed that with the increase in the dose of thermal energy supplied to the paper with the addition of PAE, its wet tensile strength increased. This applies to both the extension of the drying time and the increase in the drying temperature. Dry tensile strength tests of papers with the addition of PAE polymer showed that drying conditions were not of significant importance in that case.

Influence of drying process variables on the effective moisture diffusivity and activation energy of African oil bean seed

This study evaluated the effects of drying temperature, slice thickness and pretreatment on the effective moisture diffusivity and activation energy of African oil bean seed in a hot-air convective oven dryer. Thin-layer drying of untreated, brine and sucrose pre-treated African oil bean seed slices was investigated under four oven temperatures (40, 50, 60, 70℃) and three slice thicknesses (2, 3, 5 mm) to determine the effective moisture diffusivity (Deff) and activation energy (Ea). Fick's second law of diffusion and the plot of ln(Deff) versus Ea were used to compute the moisture diffusivity and activation energy, respectively. The results showed that Deff for African oil bean seed is in the range of 0.637 × 10−10 to 13.870 × 10−10 m2s−1, whereas Ea ranged from 18.52 to 32.01 kJ mol−1. An increase in temperature, slice thickness and pre-treatment increased the diffusivity. Brine pretreatment was found to lower the activation energy of African oil bean seed whereas the reverse is the case for sucrose pretreatment. The moisture diffusivity is useful in understanding the rate of internal moisture movement during the processing and storage of African oil bean seed. The result of activation energy is important in selecting appropriate drying variables to ensure energy conservation during the drying of African oil bean seeds.

Response Surface Optimization of Solar Drying Conditions and the Effect on the Quality Attributes and Drying Characteristics of Qula Casein.

The objective of this study was to investigate the potential application of a mixed-mode solar dryer to Qula dehydration in the Qinghai-Tibet Plateau of China. A three-factor five-level central composite rotatable design (CCD) of the response surface methodology (RSM) was employed to evaluate the influences of drying process variables on quality attributes in terms of lipid oxidation [peroxide (POV) and thiobarbituric acid reactive substance (TBARS)] and Maillard reaction (5-hydroxymethylfurfural, 5-HMF). The impact of drying temperature (30–50 °C), material thickness (5–15 mm), and wind velocity (0.4–1.4 m/s) on the color, POV, TBARS, and 5-HMF of Qula were studied. Optimum operating conditions were found to be a temperature of 43.0 °C, material thickness of 11.0 mm, and wind velocity of 1.0 m/s based on the minimum of POV, TBARS, and 5-HMF. In this condition, the values of POV, TBARS, and 5-HMF were 0.65 meq/kg, 0.516 mg/kg, and 4.586 mg water/L, respectively, which are significantly lower than for drying of Qula by open sun-drying (p < 0.05). Compared with open sun-drying, the drying time of Qula by solar drying was shortened by 61.5%. The results indicate that the mixed-mode solar dryer is a feasibility drying technology for Qula and could effectively improve the quality of products.

Spray Drying of PEG6000 Suspension: Reaction Engineering Approach (REA) Modeling of Single Droplet Drying Kinetics

The spray drying technique is suitable for different kinds of liquid dispersions and can be easily optimized to produce solid particles with tailored properties. The spray drying technique is a complex process. As an example, it is difficult to track drying kinetics, shape, and morphological changes on the scale of a single droplet. To better understand the effect of drying process variables on dried particle formation, it is useful to observe the drying of single droplets. Fundamental processes, such as mass and heat transfer, can then be easily monitored and compared with theoretical models. Acoustic levitation enables droplet/particle suspension in the air without any mechanical contact. Experiments in the acoustic levitator can be used to mimic the drying process in the spray dryer. The drying kinetics of single droplets of PEG6000 into solid particles was studied. Droplets with an initial polymer concentration (PEG6000 aqueous solution of 5%, 10%, and 15% (w/w)) were investigated at different gas drying temperatures. The size of the droplet, moisture content, and the shape evolution of the droplet/particle during the drying process were studied. The experimental drying curves were compared with the Reaction Engineering Approach (REA). The REA models were shown to provide a very good agreement for drying behavior, with a relative error of about ±3% between the initial and predicted droplet mass. This model can be implemented into the large-scale modeling of spray drying using Computational Fluid Dynamics (CFD).

Understanding the effect of coating-drying operating variables on electrode physical and electrochemical properties of lithium-ion batteries

The effect of coating and drying process variables (comma bar gap, web speed, coating ratio, drying temperature and drying air speed) on NMC622 cathode physical properties (thickness, mass loading and porosity) and electrochemical properties (gravimetric capacity, volumetric capacity and rate performance) is studied by a design of experiments approach. Electrochemical performance is assessed on half coin cells at C-rates from C/20 up to 10C. The statistical analysis of the data reveals that the cathode physical properties are mainly affected by comma bar gap and coating ratio. The electrochemical properties also show high correlations between comma bar gap and coating ratio for some C-rates. As a second evaluation, the relationship between the cathode half-cell physical characteristics with the electrochemical performance is studied through multiple linear regression analysis. A correlation mainly between coating weight and the electrochemical properties is found. Empirical linear models representing the relationship between the output and input variables are provided, showing correlation coefficients (R2) as high as 0.99.

Optimization and validation of microwave–vacuum drying process variables for recovery of quality attribute and phytochemical properties in pomegranate peels (Punica granatum L. cv. Kabul)

Optimization and validation of microwave–vacuum drying process variables for recovery of quality attribute and phytochemical properties in pomegranate peels (Punica granatum L. cv. Kabul)

Optimization of inulin production process parameters using response surface methodology

BackgroundChicory is one of the major source of inulin. In our study, Box–Behnken model/response surface analysis (RSM) was used for the optimization of spray drying process variables to get the maximum inulin yield from chicory (Cichorium intybus L.). For this investigation, the investigational plan utilized three process variables drying temperature (115–125 °C), creep speed (20–24 rpm), and pressure (0.02–0.04 MPa).ResultThe optimal variables established by applying the Box–Behnken model were as follows: drying temperature 119.20 °C, creep speed 21.64 rpm, and pressure 0.03 MPa. The obtained powdered inulin by spray drying was investigated for the yield value, identification, size, and surface morphology of the particle. The inulin obtained from the spray drying process consists of a fine molecule-sized white powder. Instead, the drying methods shows a significant effect on the morphology and internal configuration of the powdered inulin, as the inulin obtained from spray drying was of a widespread and uniform size and shape, with a rough surface on increase in temperature and smoother surface while increasing the creep speed. The findings indicate that the spray drying with optimum parameters resulted in maximum product yield.ConclusionThe outcomes of the study concluded that the product yield through spray drying technique under optimized condition is optimal as compared to other drying technique. Hence, this technique may be applied at commercial scale for the production of inulin.

Optimization of process conditions for drying of catfish (Clarias gariepinus) using Response Surface Methodology (RSM)

Drying is applied to lower the moisture content of fish to a level that can prevent the growth of mould and infestation of micro-organism and thus minimizes microbial degradation. The goal of this work was to optimize the process conditions during electrical oven drying of catfish. Moisture content (MC) was quantitatively investigated during the drying process of catfish sizes using response surface methodology (RSM) to obtain minimum moisture content. The independent process variables for the drying process were temperature (50–70 °C), product thickness (10–20 mm), salt concentration (0–20%) and drying time (480–600 min.). Two factorial interaction (2FI) regression model describing the effects of independent drying process variables on the moisture content was developed. The effects of temperature and drying time were more pronounced for MC than the thickness and salt concentration.The optimum conditions were found to be temperature = 63.43 °C, product thickness = 14.81 mm, salt concentration = 9.07% and drying time = 600 min. At these optimum conditions, moisture content was found to be 2.64% w.b. Validation of experimental results with the empirical model was evaluated using coefficient of correlation (R2) which was found for the model equation as, R2 = 0.994.

Drying kinetics and moisture diffusivity analysis of paddy in fluidised bed drying process

The drying kinetics and moisture diffusivity of paddy are studied in a fluidised bed dryer in this article. Different values of temperatures of drying air (T) at 45°C, 50°C and 55°C, velocities of drying air (V) at 2m/s, 2.5m/s and 3 m/s and paddy inventory (I) of 2 kg and 3 kg are used for drying paddy. The moisture content of paddy is reduced to a final value of around 12% (wb) from an initial value of around 28% (wb). Results showed that as the temperature and velocity of drying air increased, the drying rate also increased whereas, the drying rate decreased with an increase in paddy inventory. The moisture diffusivity is found to be increased as temperature and velocity of drying air increases, but it decreases with the inventory. A regression equation is obtained from linear regression analysis relating effective moisture diffusivity with all the drying process variables. With increase in drying air velocity and paddy inventory, the average activation energy decreases.

Drying kinetics and moisture diffusivity analysis of paddy in fluidised bed drying process

The drying kinetics and moisture diffusivity of paddy are studied in a fluidised bed dryer in this article. Different values of temperatures of drying air (T) at 45°C, 50°C and 55°C, velocities of drying air (V) at 2m/s, 2.5m/s and 3 m/s and paddy inventory (I) of 2 kg and 3 kg are used for drying paddy. The moisture content of paddy is reduced to a final value of around 12% (wb) from an initial value of around 28% (wb). Results showed that as the temperature and velocity of drying air increased, the drying rate also increased whereas, the drying rate decreased with an increase in paddy inventory. The moisture diffusivity is found to be increased as temperature and velocity of drying air increases, but it decreases with the inventory. A regression equation is obtained from linear regression analysis relating effective moisture diffusivity with all the drying process variables. With increase in drying air velocity and paddy inventory, the average activation energy decreases.

On the effect of ultrasound-assisted atmospheric freeze-drying on the antioxidant properties of eggplant

The low operating temperatures employed in atmospheric freeze-drying permits an effective drying of heat sensitive products, without any impairment of their quality attributes. When using power ultrasound, the drying rate can be increased, thus reducing the process duration. However, ultrasound can also affect the product quality. The aim of this study was to evaluate the effect of various drying process variables, namely air temperature and velocity, ultrasound power and sample size, on the antioxidant properties of eggplant (Solanum melongena L.) samples. For this reason, drying experiments were carried out at different drying temperatures (−5, −7.5, −10 °C), power ultrasound levels (0, 25, 50 W; 21.9 kHz) and air velocities (2, 5 m s−1) using different sample sizes (8.8 mm and 17.6 mm cube side). The ascorbic acid content (Jagota and Dani method), total phenolic content (Folin-Ciocalteau method), and the antioxidant capacity (FRAP method) of the dried products were considered as quality indicators of the dried samples. The increase in air velocity and temperature, as well as the sample size, significantly reduced the antioxidant potential of the dried samples (p-value < .05). For a given sample size, the application of ultrasound, at the acoustic power levels tested, did not produce significant effects on the antioxidant indicators considered. Temperature measurements inside the drying sample showed a non-negligible temperature rise when acoustic power was applied.

Relationship modelling between moisture content of flour and variables of two-cycle drying process of cassava flourusing pneumatic dryer

Moisturecontent (MC) is the most important variable in evaluating material drying performance, so the ability to predict MC in drying process is really important. This research aims to formulate the mathematic relationship between drying process variable pneumatically and moisture content of cassava flour in drying process 1 and 2 by applying dimensional analysis. In this research, there has been a design of pneumatic drying equipment and test using various treatments such as input capacity, drying air temperature, and drying air velocity. Based on the data analysis, the relationship between MC and drying process variables are as follow: Drying cycle 1: MC = (5,794287E − 22). (ρpr·Dpr3/Qi·θ)1,4085 (Tu/Tbo)-2,2504 (Vu·θ/Dpr)5,863 Drying cycle 2: MC = (2,36831E − 10). (ρprDpr3/Qi·θ)1,059 (Tu/Tbo)-4.808 (Vu·θ/Dpr)3,709 The equations have determination coefficient value 0.85, so it has big possibility to use it as alternative to predict moisture content of dried flour.

Conductive multi‐flash drying of mango slices: Vacuum pulse conditions on drying rate and product properties

In multi-flash drying, the pressure drop applied during the vacuum pulse and the number of heating vacuum pulses cycles (HVP) influence the fruit microstructure and texture. In this work, the effects of conductive multi-flash drying (KMFD) process variables on the drying kinetics, physical properties, and microstructure of mango slices were assessed. Different slopes of pressure drop (vacuum pulses of 0.98, 1.59, and 2.55 kPa s−1) and the number of HVP cycles (14 and 18 cycles for KMFD and a process with the application of 4 cycles followed by vacuum-drying KMFD-VD) were investigated. The number of HVP cycles allows obtaining both soft and crispy mangoes. Higher pressure drop slopes resulted in fruits with increased porosities (≈60%), compared with samples dried using the lower pressure drop slope (≈50%). The KMFD and KMFD-VD drying curves were similar, indicating that KMFD-VD presents operational advantages for obtaining dried fruits, reducing the number of heating-vacuum pulses. Practical applications Some fruits and vegetables have a short shelf life that limits their commercialization as fresh products and increase postharvest losses. Dehydration is an interesting alternative to the development of new products of fruits and vegetables with added value. In particular, the multi-flash drying is an innovative drying process based on the application of multiple cycles of heating-vacuum pulse to a solid food. Fruits and vegetables samples are heated (i.e., by heat conduction for the conductive multi-flash drying—KMFD) at moderate temperatures and submitted to a vacuum pulse, which causes flash drying and sample cooling. This method allows maintaining in dried products good physical–chemical properties and improving its texture. Moreover, according to the number of heating-vacuum pulse cycles and the pressure drop applied during these vacuum pulses, it is possible to obtain soft or crispy fruits. Thus, these variables can be used to control texture and produce high quality dried fruit.

A Design of Experiment approach to predict product and process parameters for a spray dried influenza vaccine

Spray dried vaccine formulations might be an alternative to traditional lyophilized vaccines. Compared to lyophilization, spray drying is a fast and cheap process extensively used for drying biologicals. The current study provides an approach that utilizes Design of Experiments for spray drying process to stabilize whole inactivated influenza virus (WIV) vaccine. The approach included systematically screening and optimizing the spray drying process variables, determining the desired process parameters and predicting product quality parameters. The process parameters inlet air temperature, nozzle gas flow rate and feed flow rate and their effect on WIV vaccine powder characteristics such as particle size, residual moisture content (RMC) and powder yield were investigated. Vaccine powders with a broad range of physical characteristics (RMC 1.2–4.9%, particle size 2.4–8.5μm and powder yield 42–82%) were obtained. WIV showed no significant loss in antigenicity as revealed by hemagglutination test. Furthermore, descriptive models generated by DoE software could be used to determine and select (set) spray drying process parameter. This was used to generate a dried WIV powder with predefined (predicted) characteristics. Moreover, the spray dried vaccine powders retained their antigenic stability even after storage for 3 months at 60°C. The approach used here enabled the generation of a thermostable, antigenic WIV vaccine powder with desired physical characteristics that could be potentially used for pulmonary administration.

Spray drying of coffee leaf extract

The coffee leaf extract formulation has been used as resistance inductor in plants and to control phytopathologies. This work aimed to study the influence of spray drying process variables with the use of maltodextrin as carrier on the characteristics of the powder, by using a central composite rotational design (CCRD). The independent variables were maltodextrin concentration (X1, 0 to 30 % w/v), coffee leaf extract concentration (X2, 2 to 32 % w/v), inlet air temperature (X3, 180 to 250 °C) and air flow rate (X4, 3.5 to 5.5 m3min-1). The response variables were collection efficiency (h), moisture content (MC), phenolic compounds content (Ph), soluble solids (S) content, wettability (We) and particle size (Me). The results showed that the combination of a higher concentrations of coffee leaf extract (X2) (32%) and lower inlet air temperatures (X3) (180°C) make the best drying performance. This process condition lead to a powder with higher Ph, S, We, Me and lower MC. Therefore, the use of high air flow rates (X4) increase the collection efficiency (h) of process and the use of low maltodextrin concentration (X1) lead to better preservation of phenolic compounds content (Ph) on coffee leaf extract powdered.

Research on the drying kinetics of household food waste for the development and optimization of domestic waste drying technique

ABSTRACTDomestic food waste drying foresees the significant reduction of household food waste mass through the hygienic removal of its moisture content at source. In this manuscript, a new approach for the development and optimization of an innovative household waste dryer for the effective dehydration of food waste at source is presented. Food waste samples were dehydrated with the use of the heated air-drying technique under different air-drying conditions, namely air temperature and air velocity, in order to investigate their drying kinetics. Different thin-layer drying models have been applied, in which the drying constant is a function of the process variables. The Midilli model demonstrated the best performance in fitting the experimental data in all tested samples, whereas it was found that food waste drying is greatly affected by temperature and to a smaller scale by air velocity. Due to the increased moisture content of food waste, an appropriate configuration of the drying process variables can lead to a total reduction of its mass by 87% w/w, thus achieving a sustainable residence time and energy consumption level. Thus, the development of a domestic waste dryer can be proved to be economically and environmentally viable in the future.

Processes for controlling the structure and texture of dehydrated banana

ABSTRACTThis study is about how to control the microstructure of dehydrated banana during drying by a multi-flash drying process. The influence of different drying methods and process variables on the formation of fruit microstructure and texture were evaluated. These processes included a conductive multi-flash drying process, conductive multi-flash drying combined with classical vacuum drying, convective drying in an oven, and vacuum drying. Density, porosity, and shrinkage of dehydrated fruit were strongly influenced by the drying process. Results showed that it is possible to control the porous structure of dehydrated banana by choosing the correct dehydration process.

ICH Q8 Guidelines in Practice: Spray Drying Process Optimization by 2&lt;sup&gt;3&lt;/sup&gt; Factorial Design for the Production of Famotidine Nanoparticles

Keeping in view the standpoint of quality by design, the current work was undertaken to optimize the process parameters in spray drying involved in the production of nanoparticles of famotidine (FAM), a drug with low oral bioavailability. Statistical experimentation approach using 23 full factorial design was utilized to optimize the spray drying process variables. Polymeric PLGA nanoparticles of FAM were formulated employing spontaneous emulsification-solvent diffusion technique. The critical process parameters (CPPs) chosen were the inlet temperature, the feed rate of the liquid and the aspiration flow rate. The influence of these CPPs on the critical quality attributes (CQAs) like % yield of the dried nanoparticles, was studied. Predicted conditions for maximum yield were: inlet temperature 150 °C, feed flow rate 4.5mL/min and aspiration airflow rate at 1490rpm which led to a yield of 52.6±0.4%. The spray dried nanoparticles were characterized for yield, size, zeta potential, morphology, in vitro drug release and mucoadhesion ability. A comparative analysis of the formed nanoparticles was done with the plain drug and excipients using XRD, DSC and FTIR techniques. The average particle size of the dried nanoparticles was found to be 324±4nm. The polydispersity index was 0.739±0.085. The release of drug from the polymeric nanoparticles followed Higuchi square root kinetics. Thus the use of statistical designing of experiment in the domain of the optimization of spray drying technique was proved to be effective to obtain spray dried nanoparticles of FAM with an appreciable yield. Keywords: Emulsification-solvent diffusion, famotidine, 23 factorial design, gastroretention, mucoadhesion, PLGA-carbopol nanoparticles, quality by design, spray drying.

Influence of spray-drying operating conditions on sunflower oil powder qualities

The main aim of the study was to develop a vegetable oil (VO) microencapsulation process using a spray drying technique with the aid of the response surface methodology (RSM). The specific objectives were to evaluate the operating condition effect on VO powder qualities and analyze the microstructure and rancidity on VO microcapsules obtained under set conditions that lead to high solid yields. Maltodextrin and hydroxypropylmethylcellulose were used as wall materials. The influence of spray drying process variables over solid yield (SY), moisture content (MC), surface oil (SO) and encapsulation efficiency (EE) was studied. All experiments led to high values of EE, while SY and MC were significantly affected by modifying spray drier conditions, allowing the enhancement of SY when the optimization process was applied. The optimized VO microcapsules presented an external surface with a continuous wall and no apparent pores; with low moisture content, high VO content retained into microcapsules and low peroxide value.

Impact of process variables on the micromeritic and physicochemical properties of spray-dried porous microparticles, part I: introduction of a new morphology classification system

This work investigated the impact of spray drying variables such as feed concentration, solvent composition and the drying mode, on the micromeritic properties of chlorothiazide sodium (CTZNa) and chlorothiazide potassium (CTZK). Microparticles were prepared by spray drying and characterised using thermal analysis, helium pycnometry, laser diffraction, specific surface area analysis and scanning electron microscopy. Microparticles produced under different process conditions presented several types of morphology. To systematise the description of morphology of microparticles, a novel morphology classification system was introduced. The shape of the microparticles was described as spherical (1) or irregular (2) and the surface was classified as smooth (A) or crumpled (B). Three classes of morphology of microparticles were discerned visually: class I, non-porous; classes II and III, comprising differing types of porosity characteristics. The interior was categorised as solid/continuous (α), hollow (β), unknown (γ) and hollow with microparticulate content (δ). Nanoporous microparticles of CTZNa and CTZK, produced without recirculation of the drying gas, had the largest specific surface area of 72.3 and 90.2 m²/g, respectively, and presented morphology of class 1BIIIα. Alteration of spray drying process variables, particularly solvent composition and feed concentration can have a significant effect on the morphology of spray dried microparticulate products. Morphology of spray dried particles may be usefully described using the morphology classification system.