Minimum Drying Time Research Articles

Optimization of a Geothermal Maize Dryer for Minimum Drying Time

Optimization of a Geothermal Maize Dryer for Minimum Drying Time

Instant decompression‐induced swell drying of banana: Machine learning and swarm intelligence embedded modeling and process optimization

AbstractA novel approach of instant decompression‐induced swell drying also known as instant controlled pressure drop‐hot air dried (ICPD‐HAD) process was applied for the process performance and quality enhancement of dried banana slices. Using a hybrid approach of particle swarm embedded methodology, the process parameters treatment pressure (TP), treatment time (TT), and duration of decompressed State (DDS) were optimized for various responses including drying time (DT), browning index (BI), rehydration ratio (RR), and total antioxidant activity (TAA). The optimized process conditions were found to be 0.1 MPa of TP, 25 s of TT, and 12 s of DDS for a minimum DT of 225 min and, maximum BI, RR, and TAA, of 6.20%, 3.40%, and 98.78% respectively. The results also demonstrated that the dried banana samples produced by the ICPD‐HAD method exhibited superior quality in terms of minimal DT and BI and maximum TAA and RR compared to those produced by the vacuum and hot air drying techniques. Microstructural investigation demonstrating the superiority of ICPD‐induced samples provided additional evidence for the minimum DT requirement. Furthermore, the use of an artificial neural network was employed to investigate the drying kinetics of the novel instant decompression‐induced swell drying process. With R2 greater than 0.99 and a minimum mean square error (MSE) of 0.000131, the 2‐4‐1 artificial neural network (ANN) architecture performed admirably as a means of optimal simulation and robust control of the drying process.Practical applicationsInstant decompression‐induced swell drying also known as ICPD‐HAD process is a novel approach for the drying of banana sample with enhanced process performance and quality attires. It is common for banana drying to cause loss of total antioxidant activity and other important functional properties like color and texture. This issue can be solved and process performance can be enhanced with less energy use by employing an innovative swell drying technique triggered by instant decompression. Therefore, the dried banana samples made using this cutting‐edge technique will be advantageous from a health point of view. This method can be used by the food manufacturing sector to produce dried bananas of a higher quality and greater consumer acceptance.

Investigation of microwave application time with constant pulse ratio on drying of zucchini.

Since nonuniform drying in the continuous microwave harms the safety and quality of dried food materials, a significant quality improvement can be achieved by controlling the application time of the microwave. This study aimed to investigate the influence of microwave application time and power at a constant pulse ratio during the drying of zucchini on different product characteristics. The samples were first exposed to microwaves with powers of 360, 600, and 900 W alternately for 10, 30, and 50 s. After drying with intermittent microwaves, the process was continued using the hot-air drying. Increasing the microwave application time and power caused a significant reduction in the total process time. The minimum drying time was obtained at 900 W and 50 s (259.44 min). Deff increased significantly by 24.4% and 34.1% with increasing application time and power, respectively. The highest shrinkage and bulk density were observed in the samples dried at 360 W and 10 s due to a longer total process time than the other treatments. Rehydration increased by 10.3% and 14.7% with increasing application time and power, respectively. A 33% decrease in energy consumption was noticed in the 900 W-50 s treatment compared to the 360 W-10 s treatment. Moreover, with increasing microwave application time and power, the lightness of the dried product decreased, and the total color difference increased. In summary, the 900 W power and 50 s application time produced a better-dried product than the other treatments considering different quantitative and qualitative properties. The results of this research can be used in the food industry to dry products using microwave and hot air to control and improve their quality.

Multi-objective optimization of high-shear wet granulation process for better granule properties and fluidized bed drying characteristics

This study determines the effects of influential process parameters of high-shear wet granulation (HSWG) on the critical process and quality attributes of the granules. The wet granules from HSWG experiments were dried in a fluidized bed dryer wherein the granule drying characteristics were analyzed by introducing Page's equation, which fits well with R2 values of above 0.95 for all the batches. Response surface methodology (RSM) based nonlinear models predicting the drying time, flow angle of repose, and surface mean diameter of the granules effectively capture the granulation phenomena with high correlation coefficients of above 0.93. Multi-objective constrained grid-search (MOCGS) optimization is utilized to optimize the HSWG process. Selected optimization results include the minimum drying time of 23 min, the minimum flow angle of repose of granules as 21° and the maximum surface mean diameter of the granules as 0.62 mm for the batch size of 1.8 kg.

Digital twin model and global sensitivity analysis of an indirect type solar dryer with sensible heat storage material: An approach from exergy sustainability indicators under tropical climate conditions

This research study presents the development of a digital twin model using artificial neural networks and global sensitivity analysis to estimate different exergy sustainability indicators (improvement potential, waste exergy ratio, and sustainability index) of a conventional indirect type solar dryer and an indirect solar dryer with a thermal storage system (ITSD-TSS) from the experimental evaluation of tomato drying under tropical climate. The artificial neural network was trained using the database generated from the solar drying process, where solar radiation, ambient temperature, wind velocity, and relative humidity were considered model inputs to estimate the annual values of the absorber plate, solar collector, and drying chamber outlet air temperatures. Subsequently, these temperatures were used to determine the exergetic sustainability indicators from a solar dryer energy balance. On the other hand, the Sobol method was used for the global sensitivity analysis, which allowed obtaining the sensitivity indices and the percentage contribution of each input variable. The experimental results demonstrated that the minimum drying time was reached at 22 h with ITSD-TSS with limestone and the drying efficiency was 12.57 %. Regarding the artificial neural network, a maximum R2 value of 0.9896 was achieved between the experimental and simulated data obtained using the Levenberg-Marquardt algorithm, and the maximum values of the absorber plate, solar collector, and drying chamber outlet air temperatures were 98.62, 81.71, and 81.64 °C, respectively. The best annual average values obtained for the improvement potential and waste exergy ratio were 389.87 W and 0.49, respectively, for the conventional dryer, and the sustainability index was 1.58, corresponding to the ITSD-TSS with beach sand. The global sensitivity analysis revealed maximum values of 0.6096 and 0.8911 for the first-order and total-order Sobol indices, respectively, and the percentage with the highest contribution was 58.4 %, corresponding to the ambient temperature in the drying chamber outlet air temperature. Finally, the economic evaluation indicated that the ITSD-TSS with limestone presented the highest annual savings with $ 1264 USD, but the conventional dryer reported the lowest payback period of 0.12 years. The methodology used in this work allows a more representative estimation of the storage system integration in an indirect solar dryer from an exergetic approach, which is essential for evaluating new technologies that integrate energy storage or other processes to improve its performance.

The Effects of roof angle, inlet gap size and drying time on dryer mass flow rate and moisture content in a chimney-dependent solar crop dryer using design of experiments (DOE)

A chimney dependent solar crop dryer (CDSCD) was designed and developed. Design of Experiments (DOE) was used to carry out experiments using a statistical three level non randomized factorial experimental design in Minitab statistical software version 19.0. The effect of three drying parameters, roof angle (º), Inlet gap size (mm), and time (h) on dryer inlet mass flow rate (kg/s) and moisture content (%) were studied. The regression results showed that there was a satisfactory fit of the model variability for both dryer inlet mass flow rate and crop moisture content. The p-value for each parameter was less than 0.005, which is statistically significant. The R-squared (R2) value was 94.67% for inlet air mass flow rate study and 99.72% for moisture content. It was observed that the optimal values for achieving a low moisture content response (≤ 24%) were roof angle of 81º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 24 hours while the optimal values for achieving high inlet air mass flow rate (≥ 0.357 kg/s) were roof angle of 51º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 5 hours. The findings could be implemented and utilized for achieving optimum ventilation and drying performances to refine dryer (CDSCD) design.

Effect of curing methods on quality and drying characteristics of turmeric

Turmeric rhizomes of Suranjana cultivar were cured by traditional and microwave methods in water and sodium bicarbonate solution and dried in hot air dryer. Effect of curing methods on moisture content, hardness, colour, curcumin content, essential oil content, total phenolic content and drying rate were investigated. Curing methods did not have significant effect on moisture content of cured rhizomes. Hardness of turmeric rhizomes decreased as curing duration increased. Microwave curing in sodium bicarbonate solution for 6 min resulted in maximum value of the colour indices, highest curcumin content (5.20%) and essential oil content (4.38%) in turmeric powder and highest dry recovery (24.20%). Curing caused significant reduction in drying time. Minimum drying time (20.84 h) was required in microwave curing in water for 8 min, whereas, uncured samples took longest time (29 h) for drying. Drying of all the turmeric rhizomes cured by different methods occurred in falling rate period.

Effects of roof angle, inlet gap size and drying time on dryer mass flow rate and moisture content in a chimney-dependent solar crop dryer using design of experiment (DOE)

A chimney dependent solar crop dryer (CDSCD) was designed and developed. Design of Experiments (DOE) was used to carry out experiments using a statistical three level non randomized factorial experimental design in Minitab statistical software version 19.0. The effect of three drying parameters, roof angle (º), Inlet gap size (mm), and time (h) on dryer inlet mass flow rate (kg/s) and moisture content (%) were studied. The regression results showed that there was a satisfactory fit of the model variability for both dryer inlet mass flow rate and crop moisture content. The p-value for each parameter was less than 0.005, which is statistically significant. The R-squared (R2) value was 94.67% for inlet air mass flow rate study and 99.72% for moisture content. It was observed that the optimal values for achieving a low moisture content response (≤ 24%) were roof angle of 81º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 24 hours while the optimal values for achieving high inlet air mass flow rate (≥ 0.357 kg/s) were roof angle of 51º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 5 hours. The findings could be implemented and utilized for achieving optimum ventilation and drying performances to refine dryer (CDSCD) design.

Process Variables Optimization for Heat Pump Drying of Roselle Calyx by Using Response Surface Methodology

Heat pump drying technology has been recognized for its capability to conserve energy consumption and product quality in drying process. Understanding the influence of drying conditions on product quality and optimisation are necessary to cut down the drying cost. In this study, the drying of Roselle calyx using heat pump dryer was optimized using response surface method where Central Composite Design (CCD) was employed to investigate the effects of independent variables: drying temperature (40-60ᵒC) and sample mass (100-300 g), on the response variables (drying time, energy consumption and colour changes). The drying study aimed to achieve minimum drying time, energy consumption and total colour changes. It was discovered that temperature factor has dominant effect on drying time while sample mass on energy consumption and colour changes. The interplay between the variables was closely related to heat transfer and moisture evaporation rates of the sample. The optimum drying conditions as determined were at drying temperature of 60ᵒC and sample mass of 100 g. Under these conditions, the drying time, energy consumption, and colour difference were 332.3 min, 27.05 kWh, and 4.29 ∆E, respectively. The optimization model was well validated since the difference between the predicted and experimental results was below 3%.

Enhancement on vacuum foam mat quality parameters of papaya powder by using chemical preservatives

Vacuum foam-mat drying is a technique that involves whipping a liquid concentration with an appropriate foaming agent into a stable foam that is then dehydrated into a thin mat of foam at a low temperature. The effect of variables on responses was determined using response surface methodology (RSM). The moisture content of raw papaya pulp was 856.023 % (db.). The total soluble solid (TSS) was tested by hand refractrometer i.e. 12.8 o Brix. Parameters such as whipping time (10 minute) , papaya pulp thickness (4 mm) and vacuum oven pressure (25 inch Hg), pH value 5.56 and TSS(10 o Brix) remain constant throughout the work. The drying time, drying rate and moisture ratio varies from 60 minutes to 840 minutes, 0.001-1.279 and 0.01-4.402 respectively. The drying duration, drying rate, and moisture ratio range from 60 to 840 minutes, respectively, 0.001-1.279 and 0.01-4.402. In experiment number 2, the ingredients, temperature (70 oC), maltodextrin 0.30 (w/w), glycerol monostearate 2.0 percent, and tricalcium phosphate 2.0 percent of dried papaya powder were combined to achieve a minimum drying time of 660 minutes. Experiments also revealed that increasing the amount of tricalcium phosphate (2%) and glycerol monostearate 2.0 percent in the materials reduced drying time, which helped to lower the moisture content of the papaya powder. As the drying time increases, the moisture ratio for all samples decreases in a nonlinear manner. The moisture ratio of each sample declined rapidly while the drying period was very short, but the rate of decrement of moisture ratio became quite slow as the drying time increased. The solubility of papaya powder is found to be as low as 69.08 percent in experiment number 24 and as high as 96.45 percent in experiment number 20. Ascorbic acid is found in the range of 88.43 to 115.75 (mg/100g) in experiment numbers 28 and 1, while beta carotene is found in the range of 10-51 (g/100g) experiment numbers 24 and 12. L* (Lightness) is varied from 53.1 to 82.79 experiment numbers 14 and 10, chromatic component a* (from green to red) is varied from 27.25 to 105.92 experiment numbers 3 and 17, and chromatic component b* (from blue to yellow) is varied from -15.92 experiment number 3 to 73.67 experiment number 10 during colour value estimation. It is reported that solubility increases with increase in maltodextrin at 5% level of significance. The interaction between maltodextrin and glycerol monostearate are significant at P

Effect of Various Drying and Dehydration Techniques on The Organoleptic Quality of Mango Leathers

Background: Mango is known as the king of fruits. It has several varieties however, some are more popular in the country including Sindhri. Each variety has its significance when used in different food products. The pulp of mango is used for developing jams, beverages, chutney (dips) etc., and sometimes preserved with some additives to be used for the production of mango leather. In general, the application of drying techniques to fruit puree yields a stable shelf-life product called fruit leather, which is of soft rubbery texture with a sweet taste and especially dehydrated.
 Objectives: To analyze the effect of various drying techniques (i.e. sun drying, oven drying, and dehydration) on the organoleptic quality (i.e. quality that affects how a consumer experiences the food via their senses e.g. look, taste, smell, and touch) of mango leather.
 Methodology: A drying experiment was performed like sun drying, hot air oven drying, and commercial dehydrator to determine the effect of drying times on the quality of mango leathers using these techniques. The effect of the storage period was also studied for the quality of mango leathers. The dried mango leathers were sensory analyzed by the trained panelists.
 Results: A minimum drying time of 8-10hours was achieved in a commercial dehydrator for mango fruit leather at 70°C. It was also observed that despite the longer dehydration time, the mango leathers produced remained equally acceptable compared to other dehydration techniques. The mango leathers dried in dehydrater at 70°C ± 2°C gave the highest score of color (6.20), texture (6.13), flavour/taste (5.88), appearance (5.88), and overall acceptability (5.85), while mango leather dried in an oven at 70°C ± 2°C has recorded a score of color (5.93), texture (5.87), flavour/taste (5.77), appearance (5.53), and overall acceptability (5.70). The storage of mango leathers had also a significant effect (p < 0.05) in the storage period of mango leathers as compared to control. A non-significant difference was also observed in all the organoleptic parameters after 10-12 weeks of storage.
 Conclusion: It is obtained from the current study that for the production of mango leather, the commercial dehydrator based drying techniques results in acceptable sensory characteristics as well as longer storage period by comparing other drying techniques, as it has a controlled environment.

Effect of different drying methods combined with fermentation and enzymolysis on nutritional composition and flavor of chicken bone powder

Chicken bone powder was dried by using spray drying (SD), hot air drying (AD), freeze drying (FD), and infrared freeze drying (IFD) in this study. Nutritional composition, antioxidant property, physical property, energy consumption, and flavor were compared, respectively. The results demonstrated that IFD powder had the highest content of amino acid nitrogen (49 mg/100 g). And in terms of polypeptide content, IFD and FD powder showed no significant difference, were obviously higher than AD and SD powder. As for antioxidant property, IFD and FD powder had higher DPPH and ·OH scavenging capacity than AD and SD powder. In addition, IFD powder had the highest L* value (74.59) and SD powder had the lowest L* value (65.35), which was consistence with the result of appearance score. Concerning flavor and sensory evaluation, IFD powder showed the highest umami value (11.85) and acceptability score (52.52) among four drying methods. Besides, the typical E-nose sensors response values of the IFD powder were closest to those of the enzymatic hydrolysate before drying and SD powder had the highest response value in all sensors. Finally on the basis of energy consumption, SD showed the minimum drying time and energy consumption.

Selection of effective technological parameters for vacuum drying of hard cheeses

The work is devoted to the study of the influence of such vacuum drying technological parameters as the layer thickness and the degree of product grinding on the process efficiency. Experiments on vacuum drying of hard cheeses have been carried out while selecting the above parameters. Their influence on the duration of the process, organoleptic assessment and mass fraction of moisture in dry products has been established. It was found that with an increase in the thickness of the product layer, the duration of dehydration increases, but this increases the productivity of the installation as a whole. There was calculated values of the product relative surface for various degrees of grinding and shape. The organoleptic assessment made it possible to establish that the best quality is characterized by cheeses dehydrated with a thickness from 10 to 30 mm. In this mode, the organoleptic score can reach 26 points. If the layer thickness increases up to 40 mm, the organoleptic score decreases to 25-24 points. The mass fraction of moisture in dry cheeses has been determined depending on the thickness of the drying layer, the shape of the product and the degree of grinding. It was found that it is advisable to dehydrate cheeses with the above grinding parameters, which provides a minimum drying time, high quality indicators of the product, minimum energy consumption, and reaching the moisture mass fraction no more than 7%.

Evaluation of the Changes in Thermal, Qualitative, and Antioxidant Properties of Terebinth (Pistacia atlantica) Fruit under Different Drying Methods

This study aims to investigate the effect of different drying methods on the thermal, qualitative, and antioxidant properties and pH of terebinth. To perform the experiments in this study, the hot air (HA), infrared (IR), microwave (MW), hot air–infrared (IR–HA), and hot air–microwave drying (MW–HA) methods were considered. The results showed that the minimum drying time was obtained by the hot air–microwave (MW–HA) method. However, the lowest specific energy consumption (SEC) and the highest energy efficiency (ηe) were obtained by the MW method. Considering the color criteria, the best method was obtained by the MW–HA method. The highest amount of rehydration ratio (RR) and the lowest shrinkage (Sb) of the dried terebinth samples were obtained using the MW dryer compared with other drying methods. The MW and MW–HA methods resulted in higher contents of total phenol content (TPC), total flavonoid content (TFC), and antioxidant capacity (AntiOX) than other methods. According to the results of this study, the most effective drying method for terebinth was determined to be the MW and MW-HA methods.

Tailoring surface wettability to reduce chances of infection of COVID-19 by a respiratory droplet and to improve the effectiveness of personal protection equipment.

Motivated by the fact that the drying time of respiratory droplets is related to the spread of COVID-19 [R. Bhardwaj and A. Agrawal, “Likelihood of survival of coronavirus in a respiratory droplet deposited on a solid surface,” Phys. Fluids 32, 061704, (2020)], we analyze the drying time of droplets ejected from a COVID-19 infected subject on surfaces of personal protection equipment (PPE), such as a face mask, of different wettabilities. We report the ratio of drying time of the droplet on an ideal superhydrophobic surface (contact angle, θ → 180°) to an ideal hydrophilic surface (θ → 0°) and the ratio of the maximum to minimum drying time of the droplet on the surfaces with different contact angles. The drying time is found to be maximum if θ = 148°, while the aforementioned ratios are 4.6 and 4.8, respectively. These ratios are independent of the droplet initial volume, ambient temperature, relative humidity, and thermophysical properties of the droplet and water vapor. We briefly examine the change in drying time in the presence of impurities on the surface. Besides being of fundamental interest, the analysis provides insights that are useful while designing the PPE to tackle the present pandemic.

Investigation of drying conditions to valorize 2-phase olive pomace in further processing

Pre-dried 2-phase olive pomace was dried until 8% moisture content of it by tray dryer. The effect of tray dryer’s process conditions in terms of drying temperature (70–90 °C), air velocity (0.5–1.8 m/s), and sample thickness (0.5–1.5) on the quality of olive pomace and system energy efficiency were investigated. Moreover, tray dryer process parameters were optimized considering of minimum drying time, minimum quality loss of olive pomace, and maximum system energy efficiency. The optimum tray dryer conditions were 85.2 °C of drying temperature, 1.72 m/s of air velocity, and 0.5 cm of sample thickness as specified by using the Design Expert packaged software. The effects of drying temperature, air velocity, and sample thickness on the physical and chemical properties of dried 2-phase olive pomace (free fatty acid and specific absorption value [K232, K270]) and the system’s energy efficiency (in terms of the moisture extraction rate and specific energy consumption) were examined.

Optimization and quality evaluation of infrared-dried kiwifruit slices.

Infrared drying characteristics of kiwifruits under natural and forced drying air convection with different conditions were investigated. An experimental study along with statistical analysis aimed to evaluate quality characteristics of infrared‐dried kiwifruit slices, in terms of drying time, rehydration ratio and shrinkage as a function of infrared power levels, slice thicknesses, slice distance from the infrared lamps, and air velocity. Response surface methodology was used for optimization of drying parameters with employing desirability function. Minimum drying time, shrinkage, and maximum rehydration ratio assumed as criteria for optimizing drying conditions of kiwifruit slices were strongly dependent on the drying conditions. All operating variables had a significant effect on total responses, but slice thickness almost was the most prominent factor. The slices dried at the highest power level, the lowest distance from the Infrared lamp, the least thickness, and air velocity showed a higher rehydration capacity than slices dried at the other conditions.

Effect of Drying Modes on Quality Characteristics of Dehydrated Green Leafy Vegetables

The present investigation was carried out for justifying the suitability of various dehydration techniques for desired quality of finished products. The commonly consumed green leafy vegetables viz. fenugreek leaves (Trigonella foenumgraecum) and spinach (Spinacia oleracea L.) were assessed for their commercial processing potential through dehydration technology. The selected fresh green leafy vegetables were washed and subjected to steam blanching. The pretreated vegetables were then dehydrated under different drying conditions i.e. sun, shade and tray drying to safe moisture level. The dried samples were evaluated for their dehydration process features, nutritional and sensory characteristics. The data on the dehydration technology revealed that tray dried green leafy vegetables found comparatively more wholesome, palatable and reported maximum retention of nutrients like vitamin C (35–47%), minerals (96%), with minimum drying time (2.30–3.30 hrs) and equilibrium moisture content (6%) as compared to rest of drying methods. The rate constant for drying of fenugreek and spinach leaves were found to be 0.0105 min−1 and 0.0088 min−1, respectively in tray drier. The tray drying method was found comparatively superior in retention of sensory quality parameters (color, texture and overall acceptability) over sun and at par with shade drying.

Instant Controlled Pressure Drop (DIC) Treatment for Improving Process Performance and Milled Rice Quality

In this study, instant controlled pressure drop (DIC) treatment was applied for enhancing both process and IR-20 rice quality. This treatment was integrated with soaking and hot air drying (soaking–DIC–hot air drying) in order to improve process performance and quality attributes of the rice. For the optimization, the effect of treatment pressure (TP), treatment time (TT) and decompressed state duration (DD) was investigated on hot air drying time (DT) and head rice yield (HRY). Optimized results were obtained by applying an integrated approach of artificial neural network (ANN) and particle swarm optimization (PSO). With values of TP, TT and DD as the inputs, 3-6-2 was found as the best ANN architecture in order to predict DT and HRY of the DIC-treated parboiled rice. Optimum process conditions as obtained from hybrid ANN–PSO approach were TP of 0.6 MPa, TT of 39 s and DD of 14 s with maximum HRY and minimum DT. The results reveal that IR-20 milled rice produced by DIC-treated parboiling method stands better than conventional method in terms of shorter drying time (DT of 200 min against 1140 min for conventional method), higher degree of gelatinization, higher percent of HRY (70% against 55% of total paddy rice for conventional method), lower broken ratio, ease of cooking and improved pasting and texture properties.

Optimization of process conditions for vacuum microwave drying of lemon peel by response surface methodology: Quality characteristics and volatile compounds

AbstractThis study evaluated for to optimization of dried lemon peel production conditions in vacuum microwave dryer as a novel drying technique by using response surface methodology (RSM) and to observation of its effects on the quality and volatile compounds. The optimum vacuum power (584 watt) and temperature (50 °C) according to the highest b* value and limonene content while the minimum drying time occurs were estimated using RSM. The volatile constituents of fresh and dried lemon peels were investigated by headspace‐solid phase micro extraction‐gas chromatography mass spectrometry, as a result, 32 and 34 compounds were identified, respectively. Furthermore, quality characteristics of the optimally developed lemon powder were studied. Dried peels had higher conservation of total phenolic compounds than fresh samples. Drying significantly affected the volatile compounds, antioxidant activity, total carotenoid, and ascorbic acid contents of lemon peel powders.Practical applicationsDrying is an important food preservation method. However, the effets of drying methods and conditions on foods quality are not clear. This study presents optimum conditions for drying lemon peels in vacuum microwave dryer and appreciates effect of drying system on some quality characteristics and volatile compounds. The data of present study will give information to food industry for installing industrial scale drying systems for aromatic products. It will be contributed to the improvement of firms' conditions that already in production.