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 ◽  
...  

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.

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
James Owusu-Kwarteng ◽  
Francis K. K. Kori ◽  
Fortune Akabanda

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.


2020 ◽  
Author(s):  
SEBIHA REHMAN ◽  
SEEMIN RUBAB

Abstract The paper presents a kinetic study of solar dried mint (Mentha spicata L.) without any pre-treatment. Mint grows effortlessly in Kashmir valley but is not obtainable throughout the year because of inconsiderate weather conditions. The genus belongs to the Labiatae family and includes large varieties with different properties. A significant quality parameter is its colour. The drying kinetics of mint leaves dried in Domestic Solar Dryer in terms of colour attributes, moisture content, drying time, non enzymatic browning, water activity, rehydration ratio was studied. This study is very useful for household scale drying of mint leaves to optimize drying process and to achieve superior quality dried product at home maintaining its colour and aroma.


2021 ◽  
pp. 243-251
Author(s):  
Sanjay Kumar Singh ◽  
Samsher ◽  
B.R. Singh ◽  
R.S. Senger ◽  
Pankaj Kumar ◽  
...  

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.


2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Masnaji R. Nukulwar ◽  
Vinod B. Tungikar

Abstract The objective of this study is to find an optimized thin-layer mathematical model suitable for drying kinetics of turmeric. Turmeric has a high moisture content which necessitates effective drying. A 10 kg, sample batch, of turmeric was dried in a solar dryer. Drying air temperatures and air velocity were observed in the range of 55 °C–68 °C and 0.7 m/s–1.4 m/s, respectively, in the drying experiments. It is seen that the moisture content of the turmeric is reduced from 77% to 11.93% in 22 h when compared with open sun drying, which required 60 h for the same reduction in the moisture content. Scheffler dish was used to generate steam for the dryer. Seven thin-layer mathematical models, cited in the literature, had been used for the study. These models were applied for different trays placed in the dryer. The result of the research and experimentation showed that the Page model fits best for drying in the steam-based dryer and open sun drying. Experimental results showed 63.33% saving in drying time, and the drying efficiency was found as 29.85%. Uncertainty in the drying efficiency was observed as 0.67%. Experimental investigation and the findings from the mathematical modeling are presented in this paper.


Foods ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 216 ◽  
Author(s):  
Aslı Aksoy ◽  
Salih Karasu ◽  
Alican Akcicek ◽  
Selma Kayacan

This study aimed to investigate the effect of different drying methods, namely ultrasound-assisted vacuum drying (USV), vacuum drying (VD), and freeze-drying (FD), on the drying kinetics and some quality parameters of dried minced meat. In this study, USV was for the first time applied to the drying of minced meat. The USV and VD methods were conducted at 25 °C, 35 °C, and 45 °C. The different drying methods and temperatures significantly affected the drying time (p < 0.05). The USV method showed lower drying times at all temperatures. The rehydration values of the freeze-dried minced meat samples were higher than those obtained by the USV and VD techniques. The samples prepared using USV showed higher rehydration values than the vacuum dried samples for all temperatures. The effects of the different drying techniques and drying conditions on the microstructural properties of the minced meat samples were investigated using scanning electron microscope (SEM). The USV method resulted in higher porosity and a more open structure than the VD method. Total color differences (ΔE) for VD, USV, and FD were 8.27–20.81, 9.58–16.42, and 9.38, respectively, and were significantly affected by the drying methods and temperatures (p < 0.05). Higher drying temperature increased the ΔE value. Peroxide values (PV) significantly increased after the drying process, and samples treated with USV showed lower PV values than the VD treated samples. This study suggests that USV could be used as an alternative drying method for minced meat drying due to lower drying times and higher quality parameters.


Author(s):  
Vikrant Tapas ◽  
Rituraj Chandrakar ◽  
Anil Kumar ◽  
Prem Shankar Sahu ◽  
Haldhar Ram Chandrakar ◽  
...  

In the Chhattisgarh state of India, the Bastar region is famous for its various forest produce collected by local inhabitants. These collected forest produce are dried in open sun drying. This chapter presents the design and analysis of solar dryer which is simple in construction and a low-cost dryer. The construction of the solar dryer will be made of galvanized mild steel sheet absorbing the sun's radiation. The hot air will be taken out through a wind turbine ventilator at the top to maintain the required humidity level in the solar dryer. The analysis shows that the temperature inside the solar dryer is evenly distributed. The suggested solar dryer will reduce the drying time of the forest produce.


2014 ◽  
Vol 953-954 ◽  
pp. 16-19 ◽  
Author(s):  
Yuttachai Keawsuntia

This research paper presents the experimental results of drying of chili by using the active solar dryer and sun drying because of chili is a commercial agricultural product of Thailand. The active solar dryer consisted of a solar collector, a drying chamber and a chimney. The small fans were installed in the solar collector of active solar dryer to provide the air flow circulated in the solar collector and a drying chamber. Drying of chili of 20 kg from moisture content 84 percent wet basis to 10 percent wet basis following the Thai Agricultural Standard (TAS 3001-2010) showed that the use of the active solar dryer to make the drying time reduced about 28.7 percent compared with sun drying because of the hot air temperature inside the drying chamber higher than the ambient temperature about 10 to 15 . The quality of dried chili from the active solar dryer better than dried chili from sun drying.


2020 ◽  
Vol 10 (10) ◽  
pp. 3533 ◽  
Author(s):  
Sebastian Romuli ◽  
Steffen Schock ◽  
Marius Kounbèsiounè Somda ◽  
Joachim Müller

The drying performance of paddy rice using an inflatable solar dryer (ISD), or also known as GrainPro® Solar Bubble Dryer™, was evaluated and compared to conventional sun drying in Burkina Faso. Drying time was around eight hours. Thermal imaging was conducted to observe temperature distribution in the ISD during drying and mixing. Shadow casting was observed in the ISD due to the round shape of the black plastic film, which reduced the temperature of the paddy rice to about 10 °C. The temperature inside the ISD was up to 13 °C higher than the ambient temperature, whereas the temperature of paddy rice on the top layer was about 5 °C higher than on the bottom. The final moisture content of paddy rice dried in the ISD and under the sun was not considerably different. Under certain circumstances, impurities in paddy rice dried in the ISD could be substantially lower than for sun drying. The aflatoxin level of paddy rice was under the maximum limit of the EU regulation. Drying paddy rice seemed to be effective to remove aflatoxin type AFG2 content. Further adaptation of the ISD design for drying operations on rough surfaces and sandy soils is suggested.


Author(s):  
Tamás Antal ◽  
Judit Tarek-Tilistyák ◽  
Zoltán Cziáky ◽  
László Sinka

Abstract This article provides results of an experimental investigation of hybrid- (MIR-FD), mid-infrared- (MIR) and freeze drying (FD) on the drying characteristics, energy consumption and quality parameters of pear. Rehydration ratio, color, texture, water activity, phenolic content and antioxidant activity were measured to evaluate the quality of dried pear products. Mid-infrared-freeze drying (MIR-FD) had the higher drying rate, which reduced the drying time by 14.3–42.9 % compared with FD method. Two empirical models were chosen to fit the drying curves and the models had the suitable R2 and RMSE values. Temperature characteristics of MIR and MIR-FD dried pear were determined in terms of interior temperature variation. The MIR-FD pear had darker color, better rehydration capacity, similar water activity, lower hardness (except of MIR-FD70°C) and highest content of chemical composition than single stage of FD products. Above all, the MIR50-60°C-FD was suggested as the best drying method for pear in this study.


2002 ◽  
Vol 11 (3) ◽  
pp. 209-218 ◽  
Author(s):  
K. PÄÄKKÖNEN

The short drying time and low product temperature makes it suitable for drying such heat-sensitive materials as herbs and vegetables. The purpose of this work was to develop a small-scale dryer for herbs and vegetables. A prototype rotary dryer combining infrared radiation with a so-called heat pump drying method was applied in drying experiments for several herbs and vegetables. The drying experiments were performed under actual crop production conditions. The drying curves for leaves of birch (Betula spp.), rosebay willowherb (Epilobium angustifolium) and dandelion (Taraxacum spp.) as well as slices of red beet (Beta vulgaris) and carrot (Daucus carota) are presented. During the drying operation, temperature and humidity of the drying air were recorded, as well as the energy consumed in drying. The quality parameters measured were water content, colour and rehydration ratio. In the present rotary dryer design, intermittent irradiation and mixing of the product enable to avoid overheating, which is particularly important for maintaining product quality. In this dryer design the drying drum slowly rotates and simultaneously mixes the product. The infrared heaters are attached to a panel, allowing the product to receive infrared radiation periodically.


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