Optimization of Fluidized Bed Drying Process of Green Peas Using Response Surface Methodology

The fluidized bed drying process of green peas was optimized using the response surface methodology for the process variables: drying air temperature (60–100°C), tempering time (0–60 min), pretreatment, and mass per unit area (6.3–9.5 g/cm²). The green peas were pretreated by pricking, hot water blanching, or chemical blanching. Product quality parameters such as rehydration ratio, color, texture, and appearance were determined and analyzed. Second-order polynomial equations, containing all the process variables, were used to model the measured process and product qualities. Rehydration ratio was influenced mostly by pretreatment followed by tempering time, temperature, and mass per unit area. Pretreatment and mass per unit area significantly affected color and texture. Higher levels of temperature and lower levels of tempering time and mass per unit area increased the rehydration ratio. The optimum process conditions were derived by using the contour plots on the rehydration ratio and sensory scores generated by the second-order polynomials. Optimum conditions of 79.4°C drying air temperature, 35.8-min tempering time, pretreatment of the once pricked peas with chemical blanching in a solution of 2.5% NaCl and 0.1% NaHCO₃, and mass per unit area of 6.8 g/cm² were recommended for the fluidized bed drying of green peas. At these conditions the rehydration ratio was 3.49.     

Optimization of Microwave-Vacuum Drying of Button Mushrooms Using Response-Surface Methodology

Button mushrooms (Agaricus bisporous) were dried in a microwave-vacuum dryer up to a final moisture content of around 6% (d.b.). The effect of microwave power level (115 to 285 W), system pressure (6.5 to 23.5 kPa), and slice thickness (6 to 14 mm) on drying efficiency and some quality attributes (color, texture, rehydration ratio, and sensory attributes) of dehydrated mushrooms were analyzed by means of response surface methodology. A rotatable central composite design was used to develop models for the responses.Analysis of variance showed that a second-order polynomial model predicted well the experimental data. The system pressure strongly affected color, hardness, rehydration ratio, and sensory attributes of dehydrated mushrooms. A lower pressure during drying resulted in better quality products. Optimum drying conditions of 202 W microwave power level, 6.5 kPa pressure, and 7.7 mm slice thickness were established for microwave vacuum drying of button mushrooms. Separate validation experiment was conducted at the derived optimum conditions to verify the predictions and adequacy of the models.     

Kinetics Study of Green Peas Drying in a Spouted Bed in the Presence of a Heat Carrier

In this study, a drying kinetics model for predicting the drying of green pea particles using a bench-scale spouted bed with heat carriers is investigated. The experiments were carried out under different operating conditions. The effect of inert particle diameter, inert particle type, and the mass ratio of inert particles to green peas was examined based on the performance of the dryer and the rate of drying. As expected, the rate of drying increased with increased mass ratio of inert particles to green peas and thermal diffusivity of inert particles.     

Infrared-Assisted Freeze Drying of Tiger Prawn: Parameter Optimization and Quality Assessment

This article presents an extensive experimental study coupled with statistical analysis on infrared (IR)-assisted freeze drying of tiger prawn (Penaeus monodon) in cuboidal geometry. The work aims to estimate quality attributes of freeze-dried prawn in terms of final product temperature (below protein denaturation temperature), rehydration ratio, and final moisture content as a function of process parameters, viz. IR temperature (55–65°C), distance between sample and IR heater (30–60 mm), sample thickness (10–25 mm) and freeze-drying time (5.5–6.5 h). Response surface methodology (RSM) has been employed using a three-parameter, three-level face-centered central composite design (FCCD) to develop multivariate regression models in order to evaluate the influence of process parameters on the quality of the freeze-dried prawn. Optimal drying conditions of 10-mm sample thickness, 60-mm sample distance from the IR heater, 65°C IR temperature, and freeze-drying time of 6.37 h have been established. Separate validation experiments at the derived optimal conditions ascertained the predictive ability of the developed model equations. The outcome of this study would contribute to the development of technical capabilities for the design of freeze dryers applicable to such high-valued foodstuffs.     

Optimizing Drying Conditions for the Microwave Vacuum Drying of Enzymes

The aim of this study was the methodological use of experimental planning for the optimization of microwave vacuum drying of enzymes using α-amylase as a model. A factorial in star designwas used to optimize the microwave vacuum–drying process, and the variables were power output and vacuum pressure. The material dehydrated by this technique was analyzed with regard to its enzymatic activity, water activity, and moisture content. Response surface methodology was used to estimate the main effects of vacuum pressure and power on the enzymatic and water activities. The experimental in star design revealed that microwave vacuum drying is influenced mainly by power. The dehydrated product showed high enzymatic activity and low water activity.     

Dielectric Properties and Optimization of Parameters for Microwave Drying of Petroleum Coke Using Response Surface Methodology

The dielectric properties of petroleum coke at five temperatures between 20 to 100 ^° C, covering different moisture content levels at 2.45 GHz, were measured using an open-ended coaxial probe dielectric measurement system. The effects of drying temperature, duration of drying, and sample mass on the moisture content and dehydration rate of petroleum coke was assessed utilizing the response surface methodology. The dielectric constant, loss factor, and loss tangent were all found to increase nearly linearly with increase in moisture content. Three predictive empirical models were developed to relate the dielectric constant, loss factor, and loss tangent of petroleum coke as a linear function of moisture content from 3–10%. An increase in temperature between 20 to 100 ^° C was found to increase the dielectric properties. The penetration depth was observed to increase linearly with decrease in moisture content in the range of 3 to 10%. A predictive empirical model was developed to calculate penetration depth for petroleum coke. Two mathematical models were established and analyzed using RSM to describe the relationship between the microwave drying conditions and the responses, moisture content, and dehydration rate. Statistical analysis with response surface regression showed that microwave drying temperature, duration of drying, and sample mass were significantly related to moisture content and dehydration rate. Based on the RSM analysis, the optimum process conditions were estimated to be a microwave drying temperature of 75 ^° C, drying duration of 10 sec, and sample mass of 60 g, with the resultant moisture content being 0.34 at a dehydration rate of 2.94 g/min.     

Investigating the Commercial Microwave Vacuum Drying Conditions on Physicochemical Properties and Radical Scavenging Ability of Thai Green Tea

The effects of drying conditions using a commercial microwave vacuum dryer on the physicochemical properties and antioxidant activity of Thai green tea were investigated. Nine different drying conditions (power 3200, 3600, and 4000 Watts vs. radiation time 20, 25, and 30 min) were applied in this study. The results showed that individual catechins, their total quantities, radical scavenging ability, and moisture content were significantly affected; however, total polyphenol content and color parameters were not significantly affected by these drying conditions. Based on this data, to obtain optimal physicochemical properties of green tea, drying conditions at 3600 Watts for 30 min were recommended.     

Optimization of Parameters for Microwave-Assisted Foam Mat Drying of Blackcurrant Pulp

Both analysis and optimization of parameters of microwave-assisted foam mat drying (MAFM), viz. microwave power, pulp load, drying time, and pulp thickness, for the dehydration process of blackcurrant pulp were performed in a household microwave oven. During MAFM drying, microwave power, pulp load, and drying time have positive effects on both vitamin C and anthocyanin content of blackcurrant pulp up to a certain level then a negative trend is observed. The increase of microwave power and decrease of pulp load accelerate the dehydration of blackcurrant pulp. The pulp thickness has a significant positive effect on both vitamin C and anthocyanin content of blackcurrant pulp. The optimum parameters valid for MAFM drying of blackcurrant pulp are as follows: microwave power of 560 W, pulp load of 65 g, drying time of 8 min, and pulp thickness of 4.46 mm. MAFM drying is a potential method for dehydrating blackcurrant pulp.     

Optimization of Freeze Drying Conditions for Purified Pectinase from Mango (Mangifera indica cv. Chokanan) Peel

Response surface methodology (RSM) along with central composite design (CCD) was applied to optimize the freeze drying conditions for purified pectinase from mango (Mangifera indica cv. Chokanan) peel. The effect of pectinase content (-2.66, 62.66 mg/mL), Arabic gum (-1.21, 10.21%, w/v), and maltodextrin (0.73, 7.26%, w/v) as independent variables on activity, yield, and storage stability of freeze-dried enzyme was evaluated. Storage stability of pectinase was investigated after one week at 4 °C and yield percentage of the enzyme after encapsulation was also determined. The independent variables had the most significant (p < 0.05) effect on pectinase activity and yield of the enzyme. It was observed that the interaction effect of Arabic gum and maltodextrin improved the enzymatic properties of freeze-dried pectinase. The optimal conditions for freeze-dried pectinase from mango peel were obtained using 30 mg/mL of pectinase content, 4.5 (%, w/v) of Arabic gum, and 4 (%, w/v) of maltodextrin. Under these conditions, the maximum activity (11.12 U/mL), yield (86.4%) and storage stability (84.2%) of encapsulated pectinase were achieved.     

Optimizing Drying Conditions for Microwave-Vacuum (MIVAC®) Drying of Russet Potatoes (Solanum tuberosum)

MIVAC® combines microwave heating with vacuum drying. Microwave power is modulated based upon product temperature and can limit overheating compared to other microwave-vacuum methods. Blanched potatoes were dried at 50, 60, and 70°C for 0 to 150 min. Potatoes dried at 70°C had a lower moisture content in less time compared to potatoes dried at 50 and 60°C, but the color of the dehydrated potatoes was affected due to overheating. Drying at 60°C for 150 min resulted in dried potatoes with acceptable color. Drying at 50°C resulted in dehydrated potatoes of acceptable color; however, it required more time.     

Optimization of Microwave Drying Biomass Material of Stem Granules from Waste Tobacco Using Response Surface Methodology

Tobacco stems, an underutilized waste in the tobacco industry, can be transformed into a viable product through the preparation of biomass material of stem granules. Response surface methodology (RSM) was used to optimize microwave drying of stem granules from waste tobacco. The effects of microwave power (35–40 kW), moisture content (25–35%), material thickness (30–50 mm), and drying time (90–150 s) on filling power and yield of stem granules were studied. Gas chromatography–mass spectroscopy (GC-MS) and scanning electron microscopy (SEM) were used to determine volatile components and microstructures of stem granules dried under optimal conditions. The filling power and yield of stem granules could be adequately fitted to a quadratic model (R ² = 0.951) and a two-factor interaction model (R ² = 0.887), respectively. The optimal conditions for microwave drying of stem granules were 35 kW, 30%, 30 mm, and 150 s. When prepared under optimal conditions, the filling power and yield of stem granules were 7.94 cm³/g and 64.06%, respectively, which differed by only 4.53 and 3.50% from model predictions. The quadratic and two-factor interaction models provided a reasonably accurate (<5% error) assessment of optimal conditions for microwave drying of biomass material of stem granules from waste tobacco stems.     

Drying Characteristics of Purslane (Portulaca oleraceae L.)

Thin layer drying rates of purslane were determined experimentally as a function of temperature with air velocity kept constant at 1.1 m/s and relative humidity below 5%. Thin layer drying data were obtained for purslane at four drying air temperatures (35, 70, 95, and 120°C). Five thin layer-drying models (Henderson and Pabis, exponential, Page, two-term exponential, and Thompson models) were fitted to the drying data. The color of purslane was determined after drying using a spectro-colorimeter (Hunter Lab) in terms of Hunter L, a, and b values. The Page model was found to be most suitable in describing the drying characteristics of purslane. New parameters developed for the model resulted in a good fit at different temperatures. Color measurement indicated that greenness decreased with an increase in drying air temperature. Typical drying times were 88.41, 138.53, 416.38, and 1371.85 min at 120, 95, 70, and 35°C, respectively.     

Drying Characteristics of Purslane (Portulaca oleraceae L.)

Abstract

Thin layer drying rates of purslane were determined experimentally as a function of temperature with air velocity kept constant at 1.1 m/s and relative humidity below 5%. Thin layer drying data were obtained for purslane at four drying air temperatures (35, 70, 95, and 120°C). Five thin layer-drying models (Henderson and Pabis, exponential, Page, two-term exponential, and Thompson models) were fitted to the drying data. The color of purslane was determined after drying using a spectro-colorimeter (Hunter Lab) in terms of Hunter L, a, and b values. The Page model was found to be most suitable in describing the drying characteristics of purslane. New parameters developed for the model resulted in a good fit at different temperatures. Color measurement indicated that greenness decreased with an increase in drying air temperature. Typical drying times were 88.41, 138.53, 416.38, and 1371.85 min at 120, 95, 70, and 35°C, respectively.     

Modeling and optimization of process parameters for supercritical CO2 extraction of Argemone mexicana (L.) seed oil

This research article deals with the determination of optimal conditions of extraction parameters (e.g. temperature (60–100?°C), pressure (200–350?bar), particle size (0.5–1.0?mm), flow rate-CO₂ (5–15?g/min), and the % of co-solvent (0.0–10% of flow rate-CO₂) resulting to the optimal cumulative extraction yield during the supercritical fluid extraction of Argemone mexicana (L.) seed oil with and without a modifier (ethanol) using a supercritical carbon dioxide as solvent. A “five-factors-three-levels” Box-Behnken design under the response surface methodology was used to show independent and interactive effects of extraction parameters. A mathematical regression model was expressed properly by a quadratic second-order polynomial equation. The maximum oil yield (42.86%) from A. mexicana seeds was obtained with the optimal conditions (85?°C, 305?bar, 0.75?mm, 11?g/min, and 9% of flow rate-CO₂) of extraction parameters. The fatty acids analysis of the seed oil was done using gas chromatography and found its suitability as bio-fuel.     

Optimization of Foaming Parameters and Investigating the Effects of Drying Temperature on the Foam-Mat Drying of Shrimp (Penaeus indicus)

In this study, foaming conditions of shrimp (Penaeus indicus) were optimized using response surface methodology (RSM) and the effect of drying temperature on drying behavior was investigated. The experiments were conducted according to face-centered central composite design for three independent variables: xanthan gum concentration (0.1–0.4% w/w), whipping time (2–6 min), and water : shrimp ratio (2:1–6:1 w/w) to minimize the foam density (FD) and the drainage volume (DV) as responses. Statistical analysis of results showed that linear terms of the models were significant (p < 0.01) except the linear term of whipping time in DV. Xanthan gum concentration 0.19% (w/w), water : shrimp ratio 4.5:1 (w/w), and whipping time 5.89 min were found to be the optimum foaming conditions. The effect of different drying temperatures (45, 60, 75, and 90°C) on drying behavior of optimized foam was then evaluated. The drying air temperature had a considerable effect on drying time and drying rate. As the temperature increased from 45 to 90°C, the drying time decreased to 90 min. Drying rate curves showed that foam-mat drying of shrimp principally occurred in the constant rate period. Different mathematical models were tested with the drying behavior of shrimp foam in the dryer. According to the results, the Weibull distribution model is superior to the other models for explaining the drying behavior. Effective moisture diffusivity was calculated and was between 1.114 × 10^?8 and 3.951 × 10^?8 m²/s within the studied temperature range. An Arrhenius relation with an activation energy value of 26.89 kJ/mol expressed the effect of temperature on diffusivity.     

Bioactive Compounds and Bioactivities of Centella asiatica (L.) Urban Prepared by Different Drying Methods and Conditions

Centella asiatica (L.) Urban has attracted significant research and commercial interest due to its many health-promoting bioactive compounds, especially phenolic compounds and triterpene saponins, which possess several functional capacities, including antioxidant activity and antimicrobial activity. Prior to its use, however, C. asiatica usually needs to be dried to extend its storage life and to prepare the material for subsequent pharmaceutical processing. The present study investigated the effects of selected drying methods and temperature on the drying characteristics, phenolic compounds, triterpene saponins, antioxidant activity, and antimicrobial activity of dried C. asiatica. Hot-air drying (HAD), combined infrared–hot air drying (IR-HAD), and low-pressure superheated steam drying (LPSSD) were carried out at various temperatures (50, 60, 70°C). The results showed that higher drying temperatures led to higher drying rates but to lower levels of total phenolic compounds, total triterpene saponins, antioxidant activity, and antimicrobial activity. At the same drying temperature, IR-HAD resulted in the highest drying rates; this was followed by LPSSD and HAD in a descending order. Nevertheless, LPSSD resulted in the highest levels of the tested bioactive compounds, antioxidant activity, as well as antimicrobial activity. LPSSD at 50°C yielded dried C. asiatica of the best overall quality.     

Optimization of an Artificial Neural Network Topology for Predicting Drying Kinetics of Carrot Cubes Using Combined Response Surface and Genetic Algorithm

In this study, the advantages of integrated response surface methodology (RSM) and genetic algorithm (GA) for optimizing artificial neural network (ANN) topology of convective drying kinetic of carrot cubes were investigated. A multilayer feed-forward ANN trained by back-propagation algorithms was developed to correlate output (moisture ratio) to the four exogenous input variables (drying time, drying air temperature, air velocity, and cube size). A predictive response surface model for ANN topologies was created using RSM. The response surface model was interfaced with an effective GA to find the optimum topology of ANN. The factors considered for building a relationship of ANN topology were the number of neurons, momentum coefficient, step size, number of training epochs, and number of training runs. A second-order polynomial model was developed from training results for mean square error (MSE) of 50 developed ANNs to generate 3D response surfaces and contour plots. The optimum ANN had minimum MSE when the number of neurons, step size, momentum coefficient, number of epochs, and number of training runs were 23, 0.37, 0.68, 2,482, and 2, respectively. The results confirmed that the optimal ANN topology was more precise for predicting convective drying kinetics of carrot cubes.     

响应面法优化微波辅助提取板栗壳色素

以板栗壳为原料,利用微波辅助提取板栗壳中的棕色素。在单因素实验的基础上,运用响应面分析法进一步对板栗壳色素的微波提取条件进行优化,并研究了各因素间的交互作用。研究结果表明,在重复提取3次的条件下,当1.0wt%Na HCO3为提取溶剂、料-液比为1∶25(g/m L)、辐照时间为6 min、微波功率为462 W,再将粗提液经酸沉、重结晶后,板栗壳色素的提取率达到了15.5%。响应面分析结果显示,功率对提取效率的影响最为显著,表明微波法可较好地应用于板栗壳棕色素的提取。     

Optimizing ethanolic hot compressed water (EHCW) cooking as a pretreatment to glucose recovery for the production of fuel ethanol from oil palm frond (OPF)

The objective of this work is to study the effects of reaction temperature, reaction time and ethanol percentage on the pretreatment of oil palm fronds (OPF) using ethanolic hot compressed water (EHCW) to enhance sugar recovery in enzymatic hydrolysis. A central composite rotatable design was used to optimize the pretreatment process conditions. All variables (individual and interactive) were found to affect glucose recovery significantly. A quadratic polynomial equation was modelled for glucose recovery by multiple regression analysis using response surface methodology (RSM). Using a 10 bar pressurized reactor, the optimum conditions for pretreatment of OPF were obtained at 180 °C, 42 min and EtOH wt.% of 26.4%. At the optimum conditions, the predicted glucose recovery was 88.48%. Experimental verification of the optimum conditions gave glucose recovery well within the estimated value of the model.     

Optimization of extraction parameters of bioactive components from defatted marigold (Tagetes erecta L.) residue using response surface methodology

Response surface methodology (RSM) was used to estimate the optimum extraction parameters, in which the antioxidant activity (AA) of the extract from the defatted marigold residue was the strongest. The AA of marigold extracts was investigated by the radical scavenging activity assays ((2,2-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH)). Results demonstrated that AA was significantly affected by the content of total phenolics (TP) and total flavonoids (TFA) (p < 0.0001). The optimal extraction parameters of marigold extracts for the highest AA by ABTS method were ethanol concentration of 79.7%, extraction temperature of 74.2 °C and time of 8.1 h, and by DPPH assay with 89.3% of ethanol concentration at 81.5 °C for 11.1 h, AA values were 2.42 and 1.86 mmol TE/g, respectively.