scholarly journals Drying characteristics and prediction of best fitted drying model for coriander leaves

2021 ◽  
pp. 243-251
Author(s):  
Sanjay Kumar Singh ◽  
Samsher ◽  
B.R. Singh ◽  
R.S. Senger ◽  
Pankaj Kumar ◽  
...  
Keyword(s):  
Removal Rate ◽  
Drying Methods ◽  
Moisture Removal ◽  
Drying Time ◽  
Sun Drying ◽  
Potassium Metabisulphite ◽  
Solar Greenhouse ◽  
Drying Models ◽  
Drying Model ◽  
Coriander Leaves

Drying experiments were conducted on coriander leaves as affected by drying methods (solar greenhouse drying and open sun drying), pretreatments (dipping in a solution of magnesium chloride + sodium bicarbonate + potassium metabisulphite, boiled water blanching containing sodium metabisulphite, and untreated), and loading densities (2.0, 2.5 and 3.0 kg/m2). Validity of three commonly used drying models were examined to predict the most suitable drying model for coriander leaves. The increased drying temperature under solar greenhouse dryer (42°C) increases the amount of moisture removal from the coriander leaves and reduces the drying time by increasing the drying rate as compared to open sun drying (29°C), at all the selected levels of pretreatments and loading densities. Chemically treated coriander leaves dehydrated under a solar greenhouse dryer required less drying time than other treated leaves and dried leaves. Nevertheless, drying methods and loading densities had significant effects, while treatment effects were marginal. It was found that reduction of moisture and moisture removal rate per unit time occurred mostly in the falling rate period except some accelerated removal of moisture at the beginning up to 150 minutes. Page's model was found most appropriate for drying coriander leaves among the selected models.

scholarly journals Effect of Pads and Thickness of Paddy on Moisture Removal under Sun Drying

2021 ◽  
Author(s):  
A. Narmilan ◽  
G. Niroash ◽  
M.I.M. Mowjood ◽  
A.T.A. Akram
Keyword(s):  
Sri Lanka ◽  
Moisture Content ◽  
Removal Rate ◽  
Initial Moisture Content ◽  
Storage Period ◽  
Moisture Removal ◽  
Drying Time ◽  
Sun Drying ◽  
Regular Time ◽  
Paddy Farmers

Background: Sun drying is a popular post-harvest operation to maintain rice quality during the storage period. Farmers use different pads and thicknesses for sun drying of paddy in Ampara district, Sri Lanka. A study was conducted to evaluate the suitability and effectiveness of the drying pad and thickness as practiced by local paddy farmers during the sun drying process.Methods: The grain with an initial moisture content of 28% (dry basis) was sun dried with four types of drying pads and five levels of thickness of grain. This experiment was conducted between 8.30 am and 4.30 pm at the South Eastern University of Sri Lanka in August 2020. The moisture contents of the grain were measured at regular time intervals.Result: It was found that the duration of drying of paddy from 28% to 13% moisture content on a dry basis was 300 to 540 minutes depending upon the drying pad and thickness. The tarpaulin is reasonable at shallow thickness with less time to reach the necessary moisture level than other drying pads. Black polythene and fertilizer bag can be utilized for sun drying of paddy at 4 cm thickness with 130 minutes. It was found that with an increase in the thickness of paddy from 0.5 cm to 4 cm, the drying time increases. A statistically significant interaction was obtained between drying pads and thickness level on moisture removal of paddy. Therefore, the moisture removal rate differs with the drying pad and thickness of the paddy under open sun drying.

scholarly journals Drying Kinetics of Sliced Pineapples in a Solar Conduction Dryer

2017 ◽  
Vol 7 (2) ◽  
pp. 14 ◽  
Author(s):  
Luqman Ebow Ibn Daud ◽  
Isaac Nyambe Simate
Keyword(s):  
Thin Layer ◽  
Average Moisture Content ◽  
Drying Time ◽  
Sun Drying ◽  
Thin Layer Drying ◽  
Drying Models ◽  
Drying Model ◽  
Thin Layer Drying Models ◽  
Drying Curves ◽  
Kinetics Of

As a means of adding value to pineapple production and minimising post-harvest losses, sliced pineapples were dried using a Solar Conduction Dryer (SCD) and appropriate thin layer drying models to predict drying were developed whilst the performance of the SCD was also investigated. For the period of the experiment, ambient temperature and temperature in the dryer ranged from 24 to 37 °C and 25 to 46 ℃ respectively. The performance of the dryer was compared to open sun drying using pineapple slices of 3-5 mm in thickness where the slices were reduced from an average moisture content of 85.42 % (w.b.) to 12.23 % (w.b.) by the SCD and to 51.51 % (w.b.) by the open sun drying in 8 hours effective drying time. Pineapple slices of thicknesses 3 mm, 5 mm, 7 mm and 10 mm were simultaneously dried in the four drying chambers of the SCD and their drying curves simulated with twelve thin layer drying models. The Middilli model was found as the best fitted thin layer drying model for sliced pineapples. The optimum fraction of drying tray area that should be loaded with pineapples was also investigated by simultaneously loading 7 mm slices of pineapples at 50, 75, and 100 percent of drying tray area. Loading the slices at 50, 75 and 100 percent of drying tray area gave overall thermal efficiencies of 23, 32 and 44 percent, respectively, hence loading pineapple slices at 100 percent drying tray area was recommended as the best.

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.

Influence of Drying Conditions and Mathematical Models on the Thin-Layer Drying of Mushrooms

2014 ◽  
Author(s):  
A. Stegou-Sagia ◽  
D. V. Fragkou
Keyword(s):  
Mass Transfer ◽  
Thin Layer ◽  
Mathematical Models ◽  
Drying Methods ◽  
Suitable Model ◽  
Drying Time ◽  
Thin Layer Drying ◽  
Drying Behavior ◽  
Drying Models ◽  
Drying Rates

In the present research, experimental data from several studies about drying behavior of mushrooms have been selected and used to compare different drying methods and different mathematical thin layer drying models to simulate mushroom drying rates. The white button (Agaricus Bisporus), the oyster (Pleurotus Ostreatus) and the milky mushroom slices have been considered for drying in different dryers such as hot air cabinet dryer and fluidized bed dryer with different slice thicknesses, drying air temperatures (45 °C to 90 °C) and drying air velocities (0.2 m/s to 5 m/s). The entire drying process has taken place in the falling rate period, assuming that internal mass transfer occurred by diffusion in mushroom slices. The study shows that the drying air temperature and the drying air velocity have an effect on the moisture removal from mushrooms and also on the drying time. Mathematical models have been proved to be useful for design and analysis of heat and mass transfer during drying processes. All the drying models considered in this study could adequately represent the thin layer drying behavior of mushrooms. Furthermore, as it is obvious, any type of mushrooms has its own most suitable model.

scholarly journals The effect of drying temperature on cup quality of coffee subjected to mechanical drying

2021 ◽  
pp. 35-41
Author(s):  
T.N. Sandeep ◽  
B.B. Channabasamma ◽  
T.N. Gopinandhan ◽  
J.S. Nagaraja
Keyword(s):  
Drying Methods ◽  
Drying Time ◽  
Drying Temperature ◽  
Sun Drying ◽  
Robusta Coffee ◽  
Temperature Regimes ◽  
Quality Rating ◽  
Drying Rates ◽  
Cup Quality

The objective of the work was to study the effect of drying temperature on cup quality of the robusta coffee subjected to mechanical drying in comparison with conventional sun drying. The robusta coffee processed by wet (parchment coffee) and dry (cherry coffee) methods were subjected to drying at different temperature regimes (40 oC, 50 oC and 60 oC) in a rotary mechanical dryer. The results of the study indicated that as the drying temperature increased, the time of drying reduced. Sun drying of parchment coffee took 48 hours (approximately seven days) to attain the desired moisture content of 11-12 per cent, while mechanical drying reduced the drying time to 16 to 24 hours. Similarly, cherry coffee subjected to sun drying took 88 hours (approximately 15 days), while mechanical drying reduced the drying time to 32 to 48 hours. The cup quality rating of coffee dried by different drying methods revealed that sun-dried robusta parchment coffee scored the highest cup rating. As the drying temperature increased, the cup quality ratings decreased. A similar cup quality rating was also observed with cherry coffee. These results indicate a considerable reduction of drying time when coffee beans are dried in a mechanical dryer. However, there is a need to regulate the drying temperature, which otherwise would negatively impact the quality of coffee. The drying temperature should not exceed 40oC for preserving the innate quality of robusta coffee because the high drying rates provoked by high temperatures can cause damage to the coffee quality due to the damage caused to the cell membranes. Overall, mechanical drying is more advantageous to sun drying in-terms of drying hours (indirectly reduces dependency on manpower) and preservation of innate quality of the coffee.

Feasibility Tests for a Two-Stage Batch Dryer for Curing Farmer Stock Peanuts1

1999 ◽  
Vol 26 (2) ◽  
pp. 68-73 ◽  
Author(s):  
C. L. Butts ◽  
M. S. Omary
Keyword(s):  
Seed Germination ◽  
Moisture Content ◽  
Removal Rate ◽  
Initial Moisture Content ◽  
Moisture Removal ◽  
Two Stage ◽  
Drying Time ◽  
Milling Quality ◽  
System A ◽  
Support Price

Abstract A two-stage batch dryer for farmer stock peanut was developed by a commercial grain dryer manufacturer and tested at a commercial peanut buying point during the 1996 and 1997 harvests. A 7.3-m diameter grain bin provided the superstructure for two peanut curing chambers. Each chamber had an approximate capacity of 18,000 kg of in-shell peanuts. Comparisons between conventional peanut curing wagons and the bin dryer were conducted. Recorded data included temperature and relative humidity in both type dryers, drying time, moisture content throughout curing, farmers stock grades, milling quality, and seed germination. A total of 451,717 kg were cured in the two-stage dryer and 215,460 kg in conventional dryers. The initial moisture content of peanuts averaged 19% wet basis and dried at an average moisture removal rate of 0.45%/hr. The moisture removal rates for the two dryers were not significantly different. The final moisture content averaged 11%. Moisture content at the time of grading averaged 9%. Farmers stock grades and milling quality were not significantly different. The average quota support price, including LSK for peanuts cured in conventional dryers, was $630.47/1000 kg compared to $636.08/1000-kg peanuts cured in the two-stage dryer. Seed germination averaged 75.8 and 76.1% for conventional and bin-dried peanuts, respectively. The twostage batch dryer was comparable to the current wagon-drying system. A single batch in the two-stage dryer was equivalent to three peanut wagons.

scholarly journals Development and effectiveness of greenhouse type solar dryer for coriander leaves

2022 ◽  
Vol 43 (1) ◽  
pp. 85-96
Author(s):  
S.K. Singh ◽  
◽  
Mr. Samsher ◽  
B.R. Singh ◽  
R.S. Sengar ◽  
...  
Keyword(s):  
Qualitative Evaluation ◽  
Ascorbic Acid Content ◽  
Cost Effective ◽  
Quality Parameters ◽  
Leafy Vegetables ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Sun Drying ◽  
Solar Dryer ◽  
Coriander Leaves

Aim: Sun drying system is not able to provide the best drying performance and quality dried produce of leafy vegetables. To facilitate better options to the farmers, this study aims to develop and evaluate a cost-effective greenhouse type solar dryer to improve shelf stability of coriander leaves. Methodology: A greenhouse type solar dryer (5m x 3m x 2.3m) was developed with the provision of rigid frame, 200 µ UV stabilized LDPE glazing material, solar collector cum drying chamber, inlet air and outlet air openings. The dryer was evaluated for its performance, drying characteristics of coriander leaves and qualitative evaluation of dried product as compared to open sun drying. Results: The greenhouse type solar dryer performed well for coriander drying with increased level of temperature inside the dryer (42oC) and 24% reduced drying time as compared to sun drying (29oC).The loading capacity, efficiency, payback period and B:C ratio of the dryer were found to be 100 kg, 70.47 %, 1.26 yr and 1.79, respectively. The drying of coriander leaves occured mostly in falling rate period. Coriander leaves dried under the dryer possessed higher values of chlorophyll content (1.356 mg g-1 of tissue), ascorbic acid content (111.257 mg 100g-1), rehydration ratio (5.302) and coefficient of rehydration (0.762) than sun dried coriander leaves with the respective values of these quality parameters being 1.097 mg g-1 of tissue, 62.37 mg 100g-1, 4.715 and 0.689, respectively.

scholarly journals Vacuum-assisted microwave drying characteristics of green bell pepper

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Vivek Kumar ◽  
Shanker L. Shrivastava
Keyword(s):  
Moisture Diffusivity ◽  
Bell Pepper ◽  
Microwave Drying ◽  
Drying Methods ◽  
Drying Time ◽  
Drying Characteristics ◽  
Hot Air ◽  
Potassium Metabisulphite ◽  
Temperature Ranges ◽  
Air Dryer

Chopped green bell pepper pieces were blanched (95 °C, 5 min) and chemically pretreated (1% potassium metabisulphite solution, 25 min at room temperature) before drying in hot air dryer (HAD) at various temperature ranges (60 – 80 °C). Three vacuum levels (200, 400, 600 mm Hg) and microwave power levels (100, 200, 300 W) were also used to dry green bell pepper samples in a vacuum assisted microwave (VAM) (2.45 GHz, 0.8 kW) dryer. VAM drying methods offered a maximum reduction by four to five times in drying time as compared to that in HAD. The logarithmic model was found to have the best fit based on high R2 and small values of reduced χ2 and RMSE.  VAM method has higher values for effective moisture diffusivity (Deff) and lower values for activation energy (Ea), in comparison to the HAD method. 

scholarly journals Post-harvest treatment of algerian broad beans using two different solar drying methods

2018 ◽  
Author(s):  
A. Boubekri ◽  
S. Chouicha ◽  
M.H. Berbeuh ◽  
D. Mennouche ◽  
I. Frihi ◽  
...  
Keyword(s):  
Linear Regression Analysis ◽  
Convective Drying ◽  
Drying Methods ◽  
Solar Drying ◽  
Analysis Method ◽  
Drying Time ◽  
Broad Beans ◽  
Drying Models ◽  
Drying Curves ◽  
Experimental Trials

This work was carried up in the objective to valorize the broad beans, largely harvested in Algeria, by solar drying means. In the present research paper, an experimental study was conducted on solar drying of broad beans by two different methods. Experimental trials were performed on a direct and an indirect laboratory scale solar dryers at Ouargla university in the southern of Algeria. Selected samples were dried at 50°C, 55°C, 60°C and 65°C. In both two applied cases, drying curves were obtained and compared. Among twelve consulted drying models the Page model was correlated with satisfaction to describe the solar drying of broad beans using a non linear regression analysis method. Operating and thermal performances of the two used drying systems were checked by the energy effeceincy and economic calculation. Obtained results showed that the direct solar drying ensures good preservation of the final product with a drying time of 5 hours. Keywords: solar drying ;  convective drying ; broad bean ; quality 

Study on the Effect of Salt Modulation upon the Maize Drying Process

2012 ◽  
Vol 430-432 ◽  
pp. 1412-1416 ◽  
Author(s):  
Jun Xing Li ◽  
Ya Qiu Zhang ◽  
Wen Fu Wu ◽  
Chun Shan Liu
Keyword(s):  
Air Temperature ◽  
Removal Rate ◽  
Moisture Removal ◽  
Drying Method ◽  
Drying Process ◽  
Moisture Change ◽  
Drying Time ◽  
Thin Layer Drying ◽  
Reasonable Choice ◽  
Drying Curve

A maize drying method of salt modulation is presented in this paper. Based on the thin-layer drying experiment [1], the effects of drying air temperature and salt amount on moisture removal rate is analyzed [2], and mathematical model equation is established on relationship between maize moisture ratio and drying time [3]. The experiment result shows that: a reasonable choice of the amount of salt, air temperature and other process parameters is useful to improve drying rate of maize. Salt modulated drying curve is exponentially. The more salt is added in, the faster the moisture removal rate. However, in the case of excessive salt, there may be a critical point of moisture change in the amount of salt until this point the faster the higher the salt amount, whereas the slower; if the critical changing point is higher than the safety moisture point, generally it will conductive to the maize moisture removal process.

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