scholarly journals A Comparative Study of the Drying Rate Constant, Drying Efficiency, Nutrients and Sensory Qualities of Dried Vegetables using Solar Dryer and Open-Air Sun Drying Methods

2013 ◽  
Vol 18 (3-4) ◽  
Author(s):  
US Onoja ◽  
JC Iroegbu ◽  
JI Eze
Keyword(s):  
Comparative Study ◽  
Rate Constant ◽  
Drying Rate ◽  
Drying Methods ◽  
Sun Drying ◽  
Solar Dryer ◽  
Sensory Qualities ◽  
Drying Efficiency ◽  
Dried Vegetables

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.

Thin-Layer Mathematical Modeling of Turmeric in Indirect Natural Conventional Solar Dryer

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Masnaji R. Nukulwar ◽  
Vinod B. Tungikar
Keyword(s):  
Mathematical Modeling ◽  
Moisture Content ◽  
Thin Layer ◽  
Air Velocity ◽  
Drying Time ◽  
Sun Drying ◽  
Solar Dryer ◽  
Air Temperatures ◽  
Drying Efficiency ◽  
Kinetics Of

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.

scholarly journals Unjuk Kerja Pengering Tenaga Surya Tipe Efek Rumah Kaca Untuk Pengeringan Cabai Dengan Perlakuan Low Temperature Long Time Blanching

2020 ◽  
Vol 13 (2) ◽  
pp. 42-58
Author(s):  
Andi Muhammad Irfan ◽  
Arimansyah Arimansyah ◽  
A. Ramli Rasyid ◽  
Nunik Lestari
Keyword(s):  
Low Temperature ◽  
Moisture Content ◽  
Greenhouse Effect ◽  
The Other ◽  
Final Moisture Content ◽  
Drying Rate ◽  
Drying Time ◽  
Solar Dryer ◽  
Long Time ◽  
Drying Efficiency

Abstrak. Penelitian ini bertujuan untuk menguji unjuk kerja pengering tenaga surya tipe efek rumah kaca pada pengeringan cabai dengan perlakuan low temperature long time (LTLT) blanching. Selain itu, pada penelitian ini juga dilakukan kajian mengenai karakteristik pengeringan cabai yang dipengaruhi oleh perlakuan LTLT blanching, terutama pada kadar air, laju pengeringan, kecepatan pengeringan, dan kualitas warna. Pengujian dilakukan dengan cara mengeringkan cabai merah dengan pretreatment LTLT blanching yang dikombinasikan dengan perlakuan merotasikan rak pengering (R) dan tanpa merotasikan rak pengering (TR). Sebagai kontrol adalah cabai yang dikeringkan tanpa blanching dan tanpa merotasikan rak pengering (K). Hasil penelitian menunjukkan bahwa perlakuan LTLT blanching yang dikombinasikan dengan merotasikan rak pengering (R) merupakan perlakuan yang terbaik, dengan kadar air akhir cabai kering sebesar 9,82% dan sesuai dengan standar SNI. Waktu pengeringan yang dibutuhkan adalah selama 5 hari. Warna cabai kering yang dihasilkan adalah yang terbaik dari dua perlakuan lainnya, dengan nilai L*, a*, dan b* untuk setelah proses LTLT blanching (sebelum proses pengeringan) dan setelah pengeringan berakhir (cabai kering) berturut-turut adalah 36,02, 38,22, 13,62, dan 32,44, 33,89, dan 10,19. Energi yang terpakai untuk pengeringan cabai adalah sebesar 596181 kJ. Perlakuan R ini juga menghasilkan efisiensi pengeringan terbaik, yaitu sebesar 34,01%.Performance of Green House Effect Type Solar Dryer in the Chillies Drying with Low Temperature Long Time Blanching TreatmentAbstract. This study aims to examine the performance of the greenhouse effect type solar dryer on drying chillies with low temperature long time (LTLT) blanching treatment. In addition, a study was also conducted on the characteristics of drying chillies and the final product affected by LTLT blanching treatment, especially in terms of moisture content, drying rate, drying speed, and color. Testing was performed by drying red chilli with LTLT blanching treatment, which was combined with the treatment of rotating dryer rack (R) and without rotating dryer rack (TR). As a control, chillies were dried without blanching treatment and without rotating dryer rack (K). The results show that the LTLT blanching treatment combined with rotating the drying rack (R) is the best treatment, with a final moisture content of 9.82% which is in accordance with SNI standards. The drying time needed is 5 days. The dried chilli color produced is the best of the other treatments, with values of L*, a*, and b* for after the LTLT blanching process and after drying ended, respectively 36.02, 38.22, 13.62, and 32.44, 33.89, 10.19. The energy used for drying chillies is 596181 kJ. This R treatment also produces the best drying efficiency, which is 34.01%.

Kinetic and Thermodynamic Characteristics of Seaweed Dried in the Convective Air Drier

2010 ◽  
Vol 6 (5) ◽  
Author(s):  
Rosalam Sarbatly ◽  
Tracy Wong ◽  
Awang Bono ◽  
Duduku Krishnaiah
Keyword(s):  
Specific Heat ◽  
Air Temperature ◽  
Flow Rate ◽  
Thermodynamic Characteristics ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Sun Drying ◽  
Drying Efficiency

This study reveals the drying kinetics, specific heat and enthalpy of seaweed dried in the convective air drier. Comparison between convective hot air and sun drying process was also studied. At 50°C air temperature with 23.45 percent relative humidity and 1.55 ms-1air flow rate, it has been found that the moisture removal required 4 hours to reach moisture content of 19.66 percent wet basis with its drying rate at 0.28 x 10-3 kg water h-1. The data of drying rate showed that the drying process took place in the falling rate period. The specific heat and initial enthalpy were found to be 1.3842 kJkg-1°C-1 and 1672.69 kJkg-1, respectively. It was observed that the drying kinetics, specific heat, and enthalpy values vary significantly as functions of air temperature which seem to have more effect when compared to air flow rate and seaweed loading. Hence, the best method for seaweed drying was to use convective air system rather than sun drying because it required less drying time and has better drying efficiency.

scholarly journals Drying Performance of Beans Using Natural Convective Step Type Solar Dryer

2020 ◽  
pp. 1-7
Author(s):  
S. Joshua Davidson ◽  
J. John Gunasekar ◽  
K. Prasanthkumar
Keyword(s):  
Solar Radiation ◽  
Moisture Content ◽  
Thermal Energy ◽  
Quality Evaluation ◽  
Collection Efficiency ◽  
Drying Rate ◽  
Drying Temperature ◽  
Solar Dryer ◽  
Drying Efficiency ◽  
Step Type

Development of appropriate technologies for conversion of solar radiation to thermal energy is essential for fruit and vegetable preservation. A natural convective step type solar dryer with 10 trays was used. The drying parameters such as drying temperature, drying rate and dryer efficiency were studied on bright sunny days from top to bottom of the dryer using unblanched and blanched beans. The maximum and minimum temperatures observed were 84ºC and 50ºC at no load, 59ºC and 75ºC using unblanched beans and 51 and 75ºC using blanched beans. While drying on a sunny day, the moisture content removed was from 72 to 14% for unblanched beans and 76 to 7.32% for blanched beans. On quality evaluation, the high rehydration coefficient was found in blanched beans (0.76) than in unblanched beans (0.52). The collection efficiency was found to be 40.92% and drying efficiency was found to be 15.85% using unblanched beans and 18.75% using blanched beans.

Effect of Different Drying Methods on the Physico-Chemical Properties of Tomato Variety 'Rio Grande'

2012 ◽  
Vol 8 (2) ◽  
Author(s):  
Ridha Fethi Mechlouch ◽  
Walid Elfalleh ◽  
Manel Ziadi ◽  
Hédia Hannachi ◽  
Mabrouka Chwikhi ◽  
...  
Keyword(s):  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Chemical Properties ◽  
Rio Grande ◽  
Microwave Drying ◽  
Drying Methods ◽  
Sun Drying ◽  
Methanolic Extracts ◽  
Solar Dryer ◽  
Physico Chemical

The aim of this work is to study the physico-chemical properties of dried tomatoes, variety Rio grande using direct solar dryer (DSD), open-air sun drying (OASD) and microwave drying (MW) with three output powers density (1w/g; 2w/g; 3w/g) at different temperatures (57, 67°C). Radical scavenging activity of tomatoes extracts was investigated. Results indicated that drying tomatoes by microwave (3W/g; 67°C) is faster than open-air sun drying (OASD) and direct solar dryer (DSD). The studied parameters (moisture, pH, °Brix, total phenolics, total flavonoids, and carotenoids content) were significantly affected by different drying processes, with minimal effects on pH. The highest activity against the DPPH radical oxidation is investigated in methanolic extracts of tomatoes dried by direct solar dryer (DSD). Nevertheless, the highest ABTS value was observed in methanolic extracts of tomatoes dried by microwave (MW) with 3w/g at 57°C.

scholarly journals Experimental Comparative Study on Reduction in the Moisture Content of Cucumber in a Double Slope Solar Dryer with Open Sun Drying Method

2019 ◽  
Vol 1276 ◽  
pp. 012054
Author(s):  
Sendhil Kumar Natarajan ◽  
K. Sankaranarayanasamy ◽  
Sindhuja Ponnusamy ◽  
Velaga Kavya Chowdary ◽  
Jitender Kumar ◽  
...  
Keyword(s):  
Moisture Content ◽  
Comparative Study ◽  
Drying Method ◽  
Sun Drying ◽  
Solar Dryer

scholarly journals Comparative Study of Three Solar Drying Methods of Adensonia digitate L. (Baobab Leaves using Drying Kinetics and Empirical Drying Models)

2021 ◽  
pp. 77-85
Author(s):  
S. A. Okaiyeto ◽  
Nathaniel Oji ◽  
Y. A. Unguwanrimi
Keyword(s):  
Comparative Study ◽  
Mixed Mode ◽  
Moisture Diffusivity ◽  
Drying Methods ◽  
Solar Drying ◽  
Drying Time ◽  
Effective Moisture ◽  
Solar Dryer ◽  
Drying Models ◽  
On Farm

A comparative study of three drying methods of baobab leaves have been conducted and reported. Mixed mode solar drying, indirect mode solar drying and open sun drying of baobab leaves were conducted based on three drying models viz a viz Lewis,. Page and Henderson and Pabis models were employed in this research. Baobab leaves dried faster when dried under the mixed mode on-farm solar dryer. Drying time reduced considerably using the mixed mode on-farm solar dryer. Drying data were fitted into Lewis, Page and Henderson and Pabis models. Henderson and Pabis model (R2=0.9999, 0.9611, 0.9656; X2= 1.0297, 0.7931, 0.7710; RMSE= 0.5859, 0.6898, 0.6802 and MBE= -0.4.135, -0.4.231, -0.4176) gave the best prediction for the mixed mode drying). In the same way Henderson and Pabis model (R2=0.7450, 0.7699, 0.8243; X2= 1.9025, 0.4026, 0.2006; RMSE= 1.0684, 0.5181, 0.4058 and MBE= -0.8966, -0.3823, 0.2789) gave the best prediction for the indirect mode drying of baobab leaves. Effective moisture diffusivity of baobab leaves varied between -6.382 X 10-04 and -1.108 X 10-03 m2/s.

scholarly journals Performance Evaluation of an Inflatable Solar Dryer for Maize and the Effect on Product Quality Compared with Direct Sun Drying

2021 ◽  
Vol 11 (15) ◽  
pp. 7074
Author(s):  
Janvier Ntwali ◽  
Steffen Schock ◽  
Sebastian Romuli ◽  
Christine G. Kiria Chege ◽  
Noble Banadda ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Moisture Content ◽  
Product Quality ◽  
Postharvest Quality ◽  
Maximum Temperature ◽  
Drying Methods ◽  
Drying Time ◽  
Sun Drying ◽  
Solar Dryer ◽  
Adverse Weather

Maize is an important staple in Africa, which necessitates immediate drying to preserve the postharvest quality. The traditional drying of maize in the open sun is prone to adverse weather and extraneous contamination. In this study, the drying performance of an inflatable solar dryer (ISD) was compared to direct sun drying (DSD) in Gombe Town, Wakiso District (Uganda) by analysing the moisture content, yeasts, moulds, aflatoxin, and colour. The maximum temperature inside the ISD reached 63.7 °C and averaged 7 °C higher than the ambient temperature. Maize was dried using both methods to a moisture content below 14% after two days. In one of the received maize lots that was already heavily contaminated after harvest, drying with DSD and ISD reduced the aflatoxin content from 569.6 µg kg−1 to 345.5 µg kg−1 and 299.2 µg kg−1, respectively. Although the drying performance in terms of drying time and product quality regarding colour, yeast, and mould was similar for both drying methods, the advantage of ISD in reducing the risk of spoilage due to sudden rain is obvious. A strategy for the early detection of aflatoxins in maize is recommended to avoid contaminated maize in the food chain.

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