Evaluation of Novel Portable Passive and Cabinet Solar Dryers in Sun Drying of Mint Leaves under Indiana Weather Conditions

2021 ◽  
Vol 64 (3) ◽  
pp. 1083-1094
Author(s):  
Diana M. Ramirez-Gutierrez ◽  
Klein E. Ileleji ◽  
Amanda J. Deering
Keyword(s):  
Thin Layer ◽  
Field Experiments ◽  
Color Change ◽  
Weather Conditions ◽  
Bacterial Count ◽  
Drying Kinetics ◽  
Drying Methods ◽  
Solar Drying ◽  
Sun Drying ◽  
Page Model

HighlightsThe Page model best predicted the drying rates of mint leaves in thin-layer laboratory experiments under cyclical temperature change and in field experiments using open-air sun drying and Dehytray and Dehymeleon solar dryers.The total time for drying mint leaves with all solar drying methods was the same (48 h).For all drying methods, the aerobic bacterial count was significantly less on dried mint leaves than on fresh leaves.Color change was less impacted by sunlight with the Dehymeleon than with the Dehytray and open-air sun drying.Abstract. The drying kinetics and quality attributes of mint leaves (Mentha spitaca) were studied to determine the drying performance of two solar drying technologies (Dehymeleon V.2 and Dehytray) and their effect on dried mint quality. Field drying experiments were carried out under weather conditions at Purdue University, West Lafayette, Indiana. Thin-layer laboratory drying experiments were conducted for whole mint leaves at three temperatures [24°C (75°F), 35°C (95°F), and 54°C (130°F)] and airflow velocity of 1 m s-1 to determine the drying kinetics for the diurnal cycles typical for solar drying. The Page model was the most suitable model to predict the drying behavior of mint leaves for both the lab and field experiments. Even though the drying rate was higher with open-air sun drying on uncovered Dehytrays than with covered Dehytrays and the Dehymeleon, the total drying time for all methods was the same (48 h). Color change in mint leaves was less impacted by sunlight for mint leaves dried using the Dehymeleon, while the Dehytray and open-air sun drying had similar results due to their exposure to direct sunlight. For all drying methods, the aerobic bacterial count was significantly less for dried mint leaves than for fresh mint leaves. The log reductions in aerobic bacterial count achieved with open-air sun drying, Dehymeleon, and Dehytray were 0.47, 2.3, and 0.40, respectively. Keywords: Diffusion, Drying kinetics, Food quality, Mint leaves, Solar drying, Sun drying, Thin-layer drying.

scholarly journals Effects of Blanching and Natural Convection Solar Drying on Quality Characteristics of Red Pepper (Capsicum annuum L.)

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
James Owusu-Kwarteng ◽  
Francis K. K. Kori ◽  
Fortune Akabanda
Keyword(s):  
Natural Convection ◽  
Quality Characteristics ◽  
Red Pepper ◽  
Plain Water ◽  
Drying Methods ◽  
Solar Drying ◽  
Drying Time ◽  
Sun Drying ◽  
Overall Acceptability ◽  
Solar Dryer

The objective of this work was to determine the effects of blanching and two drying methods, open-sun drying and natural convection solar drying, on the quality characteristics of red pepper. A 2 × 3 factorial design with experimental factors as 2 drying methods (open-sun drying and use of solar dryer) and 3 levels of pepper blanching (unblanched, blanched in plain water, and blanched in 2% NaCl) was conducted. Dried pepper samples were analysed for chemical composition, microbial load, and consumer sensory acceptability. Blanching of pepper in 2% NaCl solution followed by drying in a natural convection solar dryer reduced drying time by 15 hours. Similarly, a combination of blanching and drying in the solar dryer improved microbial quality of dried pepper. However, blanching and drying processes resulted in reduction in nutrients such as vitamin C and minerals content of pepper. Blanching followed by drying in natural convection solar dryer had the highest consumer acceptability scores for colour and overall acceptability, while texture and aroma were not significantly (p>0.05) affected by the different treatments. Therefore, natural convection solar dryer can be used to dry pepper with acceptable microbial and sensory qualities, as an alternative to open-sun drying.

scholarly journals Thin-layer mathematical modeling of apple slices drying, using open sun and cabinet solar drying methods

2021 ◽  
Vol 4 (2) ◽  
pp. 43-52
Author(s):  
Abdul Wasim Noori ◽  
Mohammad Jafar Royen ◽  
Juma Haydary
Keyword(s):  
Thin Layer ◽  
Mathematical Models ◽  
Water Activity ◽  
Model Fitting ◽  
Coefficient Of Determination ◽  
Drying Methods ◽  
Solar Drying ◽  
Drying Time ◽  
Climate Conditions ◽  
Thin Layer Drying

This paper aims to investigate the effect of climate conditions such as ambient temperature, humidity, pressure, sun radiation and pollution on sliced apples quality and drying time which are dried in an indirect forced cabinet solar drying (IFCSD) and open sun drying (OSD) systems. Both experiments were implemented at same place (Kabul, Afghanistan) and time. The IFCSD yield for saving time is 42.8 % which is more effective than drying in the OSD system. Simultaneously with the decreasing of sliced apple weight from 512.9 g down to 73.9 g, the water activity decreased from 0.955 down to 0.355 in the IFCSD system. For OSD system, the sample weight decreased from 512.6 g down to 78.4 g and its water activity from 0.955 down to 0.411. On the experiment day the average sun radiation was 571 w/m2 . The pressure drop between inlet and outlet of the dryer was 0.1 kPa. Different thin-layer mathematical models were investigated to identify the best model fitting the experimental data. The mathematical models’ performances were investigated by comparing the coefficient of determination (R 2 ), reduced chi-square (X2 ) and root mean square error (RMSE) coefficients. From all 11 applied thin-layer drying models the Page, Approximation diffusion, Verma et al and Midilli and Kacuk models are more fitted to our data.

scholarly journals Influence of Surface Reflection (Albedo) in Simulating the Sun Drying of Paddy Rice

2020 ◽  
Vol 10 (15) ◽  
pp. 5092
Author(s):  
Ana Salvatierra-Rojas ◽  
Victor Torres-Toledo ◽  
Joachim Müller
Keyword(s):  
Field Experiments ◽  
Positive Impact ◽  
Weather Conditions ◽  
The Philippines ◽  
Paddy Rice ◽  
The Sun ◽  
Transient Model ◽  
Surface Reflection ◽  
Sun Drying ◽  
Drying Model

The sun drying of agricultural products is a complicated process involving heat transfer, mass transfer, and variable weather conditions. Surface reflection (albedo), a crop’s radiative property, plays an essential role in energy balance, and understanding its contribution can improve the thermal analysis. In this study, field experiments were conducted in the Philippines to explore the influence of surface albedo on the sun drying of paddy rice. First, we implemented energy and mass balance equations in a transient model with the surroundings using a graphical programming language in Matlab/Simulink®. Second, we identified the influence of albedo on the sun drying model by using a sensitivity analysis. Third, we investigated the relationship of paddy rice albedo and the solar zenith angle. Lastly, we integrated the albedo function into the sun drying model. The simulation outputs were validated with field experiments. A better estimation of the measured exit temperature and instantaneous mass were obtained when a variable albedo was applied. This study makes clear that introducing a variable albedo has a positive impact on model improvement. This information is important for application in solar drying technologies, so that the drying process can be better assessed.

scholarly journals Cabya (Piper retrofractum Vahl) fruit under open sun drying: drying behavior and modeling of thin layer drying kinetics

2020 ◽  
Vol 542 ◽  
pp. 012001
Author(s):  
L C Hawa ◽  
Ubaidillah Ubaidillah ◽  
F N Afifah ◽  
N I W Yosika ◽  
A Nurlaily ◽  
...  
Keyword(s):  
Thin Layer ◽  
Drying Kinetics ◽  
Sun Drying ◽  
Thin Layer Drying ◽  
Drying Behavior ◽  
Piper Retrofractum

Mathematical Modelling of Thin Layer Sun and Solar Drying of Cassava Chips

2010 ◽  
Vol 6 (6) ◽  
Author(s):  
Toyosi Y Tunde-Akintunde
Keyword(s):  
Thin Layer ◽  
Correlation Coefficients ◽  
Moisture Diffusivity ◽  
Solar Drying ◽  
Drying Time ◽  
Drying Characteristics ◽  
Page Model ◽  
Thin Layer Drying ◽  
Rate Period ◽  
Pretreatment Conditions

In this paper, the effect of sun and solar drying and pretreatment conditions (soaking in water; soaking in water and then blanching; blanching and then soaking) on the drying characteristics and kinetics of cassava chips were investigated. The drying time was shorter for samples pretreated by soaking only (SK) compared to the others. It was observed that pretreatment conditions and drying method significantly (P < 0.05) affected the drying rate. The drying for all experiments occurred in the falling rate period with no constant rate period. Four mathematical models were studied for the description thin layer drying characteristics of pretreated cassava chips. The models considered were the Henderson and Pabis, Newton, Logarithmic and the Page model. Comparing the correlation coefficients (R2), chi-square (c2) and root mean square error (RMSE) values of four models, it was observed that the highest values of R2 and lowest ?2 and RMSE were obtained using Page model. This shows that the Page model represents drying characteristics better than other models. The effective moisture diffusivity values were estimated from Fick’s diffusional model. These values obtained for solar dried samples were generally higher than those obtained for sun dried samples.

Thin Layer Modeling of Grated Coconut Drying

2014 ◽  
Vol 660 ◽  
pp. 367-372
Author(s):  
Muhammad Hanif Zainal Abidin ◽  
Sulastri Sabudin ◽  
Jamal Hazri Zakaria ◽  
Mohd Faizal Mohideen Batcha
Keyword(s):  
Thin Layer ◽  
Scale Up ◽  
Drying Kinetics ◽  
Coefficient Of Determination ◽  
Drying Methods ◽  
Predictive Capability ◽  
Statistical Parameters ◽  
Chi Square ◽  
Increasing Demand ◽  
Kinetics Of

With the increasing demand for new and energy efficient drying methods of agricultural products, various techniques were deviced by researchers around the world. This techniques usually developed in laboratory scale prior to scale-up for actual industrial application. During this stage, modeling usually involved to aid scaling up process. This paper presents the modeling of drying kinetics of grated coconut using three semi emperical thin layer model. These models were Logarithmic, Modified Handerson and Pabis, and Verma et al models. Moisture ratio predicted by these models were compared against experimental drying carried out at four temperatures: 50°C, 60°C, 70°C and 80°C. The performance of these models were analyzed statistically using non-linear regression using LabFit software. The statistical parameters analyzed were coefficient of determination (R2), reduced Chi-square (X2), Root Mean Square Error (RMSE) and Residuals. Higher R2 with lower X2, RMSE and Residuals implies good predictability of the models. From the analysis, it was found that Logarithmic model yields the best predictive capability of grated coconut drying kinetics with R2 = 0.9996387, X2 =0.505535x10-3, RMSE = 0.00623597 and Residuals = 0.0703607.

Drying Kinetics of Tomato Slices in Vacuum Assisted Solar and Open Sun Drying Methods

2007 ◽  
Vol 25 (7-8) ◽  
pp. 1349-1357 ◽  
Author(s):  
P. Rajkumar ◽  
S. Kulanthaisami ◽  
G. S. V. Raghavan ◽  
Y. Gariépy ◽  
V. Orsat
Keyword(s):  
Drying Kinetics ◽  
Drying Methods ◽  
Sun Drying ◽  
Kinetics Of

scholarly journals Effect of Drying Methods on the Physico-chemical Characteristics and Antioxidant Capacity of Taro, Sweetpotato, Stevia and Malunggay Leaves

2017 ◽  
pp. 88-99
Author(s):  
Inish Chris Mesias ◽  
Julie Tan ◽  
Daniel Leslie Tan ◽  
Benjamin L. Cinto
Keyword(s):  
Antioxidant Capacity ◽  
Bulk Density ◽  
Water Activity ◽  
Enzymatic Browning ◽  
Chemical Characteristics ◽  
Drying Methods ◽  
Solar Drying ◽  
Rehydration Ratio ◽  
Sun Drying ◽  
Physico Chemical

Fresh leaves are sensitive to high temperature so that appropriate drying method should be selected to dry leaves. This study aimed to determine the effect of drying methods on the physico-chemical characteristics and antioxidant capacity of taro (Colocasia esculenta), sweetpotato (Ipomea batatas), stevia (Stevia rebaudiana), and malunggay (Moringa oleifera) leaves. Fresh, healthy and mature leaves of taro, sweetpotato, stevia, and malunggay were subjected to solar drying, mechanical drying, and sun drying. The parameters evaluated in this study included moisture content, rehydration ratio, bulk density, water activity, total chlorophyll, antioxidant capacity, and non-enzymatic browning. Results showed that solar drying obtained the highest moisture removal capacity, rehydration ratio and water activity reduction while sun drying had the least. However, it was also with solar drying that the degree of non-enzymatic browning was the highest. Minimum bulk density was attained using solar and mechanical drying. In terms of chlorophyll content, mechanical drying had the highest. No apparent difference at p<0.05 between solar and sun drying methods was observed in terms of their effects on chlorophyll retention and antioxidant capacity. Variable effects of the different drying methods include little or no change, significant declines or enhancement of the leaves' physico-chemical and antioxidant attributes.

THIN-LAYER DRYING KINETICS OF SESAME HULLS UNDER FORCED CONVECTION AND OPEN SUN DRYING

2007 ◽  
Vol 30 (3) ◽  
pp. 324-337 ◽  
Author(s):  
MAJDI A. AL-MAHASNEH ◽  
TAHA M. RABABAH ◽  
MOHAMMAD A. AL-SHBOOL ◽  
W. YANG
Keyword(s):  
Thin Layer ◽  
Forced Convection ◽  
Drying Kinetics ◽  
Sun Drying ◽  
Thin Layer Drying ◽  
Kinetics Of
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