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.     

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.     

Optimization of Vegetal Pear Drying Using Response Surface Methodology

The aim of this work was to optimize the drying process of vegetal pear and minimize energy resources (cost) under prefixed limits involving vegetal pear moisture, color, and productivity. The optimization of vegetal pear drying was made by using response surface methodology (RSM) for minimum process cost and color difference between fresh and dried samples (moisture ≤0.10 g water g d.m.^?1). A pilot-plant dryer was used for dehydrating vegetal pear slices (0.5 cm thickness). The tests were carried out at different air temperature (60 to 70°C), samples diameter (4 to 7 cm), and pretreatment with ascorbic acid solutions (0–0.1% w/w). The optimum drying conditions were found at air temperature of 63°C with 5-cm sample diameter and 0.075% of ascorbic acid concentration. On the optimized drying conditions, dried vegetal pear presented values with moisture content of 0.052 g water g d.m.^?1, color difference of 11.65, production rate of 0.0073 kg h^?1, and total cost of $30.58/kg dried product^?1     

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.     

Microencapsulation of Gac Oil by Spray Drying: Optimization of Wall Material Concentration and Oil Load Using Response Surface Methodology

The objective of this study was to optimize the wall material concentration and the oil load on the encapsulation of Gac oil using spray drying by response surface methodology. Results showed that the quadratic polynomial model was sufficient to describe and predict encapsulation efficiencies in terms of oil, β-carotene, lycopene, peroxide value (PV), moisture content (MC), and total color difference (Δ E) with R ² values of 0.96, 0.95, 0.86, 0.89, 0.88, and 0.87, respectively. Under optimum conditions (wall concentration of 29.5 % and oil load of 0.2), the encapsulation efficiencies for oil, β-carotene, lycopene, PV, MC, and Δ E were predicted and confirmed as 92 %, 80 %, 74 %, 3.91 meq/kg, 4.14 % and 12.38, respectively. The physical properties of the encapsulated oil powders obtained by different formulations were also determined. It was concluded that the protein-polysaccharide matrix as the wall material was effectively used for spray-drying encapsulation of Gac oil.     

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.     

Optimization of Food Waste Bioevaporation Process Using Response Surface Methodology

A proven bioevaporation process was used to treat food waste (FW) by mixing ground FW with biodried sludge (BS). Organic loading (OL), moisture content (MC), and air flow rate (Q_g) showed significant influences on FW bioevaporation performance. Single-parameter experiments for MC and Q_g were conducted and ranges were determined to be 55–67 wt% and 0.04–0.14 m³/kg TS_mixture · h, respectively. In order to optimize the FW bioevaporation process, a central composite design (CCD) and response surface method (RSM) were applied over the preselected ranges of OL (0.00–0.16 kg VS_FW/kg TS_BS), MC (50.91–71.09 wt%), and Q_g (0.01–0.17 m³/kg TS_mixture · h). The results indicated that OL of 0.06 kg VS_FW/kg TS_BS, MC of 59.2 wt%, and Q_g of 0.09 m³/kg TS_mixture · h were the optimal conditions for the FW bioevaporation process. Water evaporation of 123.1% and VS degradation of 108.4% were obtained under these estimated optimal conditions.     

Optimization of Phospholipid Nanoparticle Formulations Using Response Surface Methodology

The present study deals with the optimization of phospholipid liposome formulations to mimic red blood cells. Optimization of different concentrations of distearylphosphatidylcholine, dipalmitoylphosphatidylcholine, and phosphatidylserine at a fixed concentration of lecithin and Tween^® 80 was done using response surface methodology. The optimized formulation produced liposomes with a particle size in the range of 112–196 nm. The optimized formulation shows low encapsulation efficiency at low levels of insulin but increases at higher loading levels. Formulated vesicles fulfill the size requirement for intravenous drug delivery. The present system is environmentally friendly with respect to biodegradability and biocompatibility.     

Modelling of Fish Drying Kinetics Using a Combination of Surface Response Methodology and Diffusional Models

ABSTRACT

Drying is a common fish preservation technique used in developing countries. Analysis of process factors involved in controlled fish drying permits process optimization and assists in design of suitable dryers. Various methodologies, with models of different complexities (analytical, semi–empirical and empirical models), have been used to investigate fish drying kinetics. The original feature of this study is the combined use of surface response methodology and diffusional models. In a limited number of experimetns, this combination allowed development of a predictive tool for assessing fish drying mechanisms and drying time.     

Supercritical CO2 Extraction Optimization of Onion Oil Using Response Surface Methodology

Response surface methodology was employed to optimize the conditions of supercritical CO₂ extraction of the oil from freeze‐dried onion powder. The effects of pressure, temperature and extraction time on the yield of oil were investigated. The maximum extraction yield of 4.69 ± 0.04 g/kg dry basis was achieved at a pressure of 20.6 MPa, a temperature of 40.6 °C, a time of 260 min, a CO₂ flow rate of 22 L h^–1, and an entrainer ratio of 0.1 mL absolute ethanol per gram dry basis. The chemical composition of the oil was analyzed by gas chromatography‐mass spectrometry. The most representative compounds of the essential oil were organosulfur‐containing compounds and, among these, the main constituents were methyl 5‐methylfuryl sulfide (18.30 %), methyl 3,4‐dimethyl‐2‐thienyl disulfide (11.75 %) and 1‐propenyl propyl disulfide (9.72 %).     

Optimization of Osmo-convective Dehydration Process for the Development of Honey-ginger Candy Using Response Surface Methodology

Osmotic dehydration of ginger with honey is an interesting alternative for the development of confectionary-based functional food with extended shelf life. Response surface methodology (RSM) was used to investigate the effects of process variables on solid gain, water loss, and overall acceptability of honey-ginger candy. The process variables included blanching time (6–10 min), osmotic solution temperature (30–50°C), immersion time (90–150 min), and convective drying temperature (50–70°C). The honey to ginger ratio was 4:1 (w/w) during all the experiments. Ginger cubes were blanched before osmotic dehydration to increase the permeability of the outer cellular layer of tissue. After osmotic concentration of ginger with honey, convective dehydration was done to final moisture content of 3–5% (w.b.) to make it a shelf-stable product. Finally, osmo-convectively dried ginger was coated with sucrose for candy preparation. The optimum osmo-convective process conditions for maximum solid gain, water loss, and overall acceptability of honey-ginger candy were 7.07 min blanching time, 50°C solution temperature, 150 min immersion time, and 60°C convective drying temperature.     

Optimization of the Microencapsulation of Lemon Myrtle Oil Using Response Surface Methodology

Response surface methodology (RSM) was applied to study the effects of types of wall materials (modified starch + maltodextrin and whey protein concentrate + maltodextrin), feed concentration, oil concentration, and outlet air temperature on oil retention and surface oil content of the encapsulated powder. The results revealed that the oil retention was significantly (P < 0.05) affected by the constant term of types of wall materials and the linear term of feed concentration but seemed to be almost independent (P > 0.05) of experimental range of oil concentration and outlet air temperature. The types of wall materials, oil load, and outlet air temperature showed a significant (P < 0.05) influence on surface oil content. The types of wall materials (Hi-Cap and WPC) also influenced significantly the oil retention and surface oil content. Based on the limited range of experimental conditions used in this work, it was not possible to choose the wall materials that can give both high oil retention and low surface oil content. Disregarding the effect of wall material, an optimum response was obtained at 40% of feed concentration (w/w), 18% of oil concentration, and 65°C of outlet air temperature.     

Optimization of Lipase-Catalyzed Interesterification of Flaxseed Oil and Tricaprylin Using Response Surface Methodology

The biosynthesis of structured lipids (SL) in organic solvent media was carried out by the interesterification of flaxseed oil (FO) and tricaprylin (TC), using Novozym 435. The bioconversion yield (BY, %) of medium-long-medium type SL, including C-caprylic and Ln-linolenic acids (CLnC), La-linoleic acid (CLaC) and O-oleic acid (COC), was monitored. Response surface methodology was used to obtain significant models for the responses, on the basis of a five level, five variable central composite rotatable design. In the experimental preliminary trials significant reaction parameters, including reaction temperature (T _r), TC/FO molar ratio (M _r), enzyme concentration (E _c), reaction time (R _t) and initial water activity (a _w), were considered for optimization. Significant models for CLnC, CLaC and COC were determined after regression analysis with backward elimination. The optimal conditions, generated for a maximum CLnC, CLaC and COC, were found to be 54.50–56.25 °C for T _r, 6.23–6.25 mol/mol for M _r, 2.68–3.13 % for E _c, 36.58–37.50 h for R _t and 0.15–0.33 for a _w. Under these optimum conditions, the BY of CLnC, CLaC and COC was predicted to be 32.48–36.67, 3.26–3.38 and 5.79–6.16 %, respectively.     

Optimization of Selective Lipase-Catalyzed Feruloylated Monoacylglycerols by Response Surface Methodology

The use of solvent engineering to achieve selective enzymatic synthesis of feruloylated acylglycerols during the transesterification of ethyl ferulate with TAG was investigated. Novozym 435 catalyzed transesterification of ethyl ferulate and TAG resulted in a mixture of feruloylated monoacylglycerols (FMAG) and feruloylated diacylglycerols (FDAG). These feruloylated acylglycerols have recently received much attention because of their health benefits, antioxidant properties and UV absorption. However, FMAG in a pure form is more advantageous than the FMAG–FDAG mixture in exhibiting stabilizing, emulsifying and conditioning properties. Thus, it is significant to perform efficient selectivity in the synthetic process. In this present study, the effect of various solvent mixtures, including unitary, binary and ternary organic media selective enzymatic synthesis of feruloylated acylglycerols was investigated by response surface methodology. Selectivity towards FMAG substantially increased from 14.5% in the unitary solvent n-hexane to 94.2% in the binary mixtures of 2-methyl-2-butanol (2M2B) and toluene (1:1, v/v). The maximum conversion achieved was 75.4% in this binary mixture medium. Analysis of variance (ANOVA) showed that 99.6% of the observed variation was explained by the polynomial model. Lack of fit analysis indicated that the regress equation was adequate for predicting the degree of the selectivity.     

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.     

Optimization of Crotonaldehyde Oxidation Catalyst using Response Surface Methodology

Crotonic acid was produced by oxidation of crotonaldehyde over molybdophosphoric acid supported on activated carbon. The full 2³ central composite design was performed and aimed at optimizing oxidation catalysts to maximize the yield of crotonic acid. Response surface methodology was applied to obtain a second‐order polynomial model and to generate the optimum conditions, with a loading of molybdophosphoric acid of 0.25, mass ratio of catalyst to crotonaldehyde of 0.025 and mass ratio of vanadium pentoxide to molybdophosphoric acid of 0.08. The crotonic acid yield was 66.7 % under these conditions. Three experiments were conducted using the same optimum conditions, and therefore, good agreement was observed between the experimental data and the predicted values obtained from the model, by comparison     

基于响应面法的水辅助共注塑管件的工艺参数优化

以最小总壁厚及内层壁厚为目标,基于响应面法（RSM）对成型工艺参数进行优化。由单因素实验确定总壁厚和内层熔体壁厚的主要影响因素;由Plackett Burman试验确定关键因素;再通过Box Behnken试验设计和响应面法分析与优化,获得最小总壁厚和内层熔体壁厚的工艺条件为：注水压力7.5 MPa,注水延迟时间2s,内层熔体温度215℃;在优化条件下,利用Design-expert模型预测总壁厚和内层壁厚与实验结果吻合较好,表明响应面法能够优化水辅助共注塑管件最小壁厚的工艺参数。     

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.     

Combined Microwave-Vacuum and Freeze Drying of Carrot and Apple Chips

A combination of microwave-vacuum (MWV) drying and freeze drying was investigated as potential means for drying carrot and apple chips. The sample was first dried by microwave-vacuum to dehydrate some amount of internal free water and then by freeze drying to a final moisture content of less than 7% (wet basis). Chemical properties (carotene and vitamin C retention) and physical properties (shrinkage, color, texture, and rehydration ratio) of carrot and apple slices dried by this method were evaluated and compared with those dried by freeze drying alone, MWV drying alone, and conventional hot air drying, respectively. The comparison showed that the carotene retention of carrot slices and the vitamin C retention of apple slices dried by the current method were close to those of freeze-dried carrot and apple slices and much better than those of conventional hot air–dried ones. The samples prepared by the current method exhibited very close rehydration capacity, color retention, and texture with those of the freeze-dried ones but with a little higher shrinkage. However, the samples still showed the attractive external appearance without marked warp.     

响应面优化法研究果糖苯酚树脂胶黏剂的合成

以果糖代替甲醛,在碱性条件下合成了果糖苯酚树脂胶黏剂。用响应面优化法对果糖苯酚树脂的合成条件进行了优化。以树脂黏度为考察指标,根据Box-Behnken的中心组合设计原理对实验进行设计和结果分析。用响应面优化法研究了温度、时间和催化剂用量对反应的联合影响,得出最佳工艺条件为:反应温度72.36℃,反应时间6.96h,催化剂用量7.98%。在此条件下,树脂的黏度为27.67s。同时用红外光谱(IR)对树脂结构进行了分析。