scholarly journals Microwave drying of corn seeds: Effect of Temperature on Drying Time, Energy Consuption and Germination Rate

Author(s):  
Ángel Hernández Moreno ◽  
Rafael Hernández-Maqueda ◽  
Isabel Ballesterios ◽  
Carlos Torres-Miño

Previous studies on the microwave drying of corn seeds have shown that the process parameters employed play a very important role in determining the properties and quality of this grain (Gürsoy et al, 2013). Among these parameters, the drying temperature has a fundamental role (Nair et al, 2011). The main objective of this work is to evaluate the effect of temperature on drying time, energy consumption and germination rate of corn seeds after they have been dried with microwave energy. To achieve the proposed objective, the drying process of these seeds was carried out in a rotating turntable domestic microwave oven (LACOR Model 69330), with a capacity of 30 liters and a total output power of 900 W, fitted with a PID temperature controller Eurotherm 3216 L. In this oven, 100 g of corn seeds, with an initial humidity of approximately 20%, was heated up to 3 drying temperatures (35, 55 and 75 °C). The seeds were weighed every 30 minutes and the drying process was considered completed when a humidity of 12 % was obtained. For each drying temperature studied, the experiments were carried out in duplicate. In each experiment, the electrical energy consumption was measured using a FLUKE 1735 energy analyzer. A sample of the dried seeds was subject to germination tests in a petri dish using filter paper and a volume of distillate water of 20mL to achieve sufficient humidity for them to sprout. Table 1 shows the average values obtained from the variables evaluated for each drying temperature.   Table 1. Results of the microwave drying experiments of the corn seeds at different temperatures and their germination tests. Drying temperature (ºC) Drying time to reach a humidity of 12% (min) Energy consumption (Wh) Germination rate (%) 35 345,0 880,3 90,0 55 118,5 330,0 81,3 75 73,5 183,9 12,0   As can be seen in Table 1, the temperature exerts a significant influence on the drying process and the germination rate of the corn seeds. An increase in the drying temperature causes a simultaneous decrease in drying time (∿ 78%) and in energy consumption (∿ 79%), which are very positive aspects. However, there is also an unacceptable decrease (∿ 87%) in the germination rate of the corn seeds.   References Gürsoy, S., Choudhary, R., Watson, D.G. Int. J Agric. & Biol. Eng., 2013, 6, 1, 90–99.Nair, G.R., Li, Z., Gariepy, Y., Raghavan, V. Drying Technology, 2011, 29, 11, 1291-1296.

2020 ◽  
Vol 4 (4) ◽  
pp. 422-431
Author(s):  
Iqbal Fahri Tobing ◽  
Mustaqimah Mustaqimah ◽  
Raida Agustina

Abstrak. Pengering tipe Tray Dryer merupakan salah satu alat pengering rak atau pengering kabinet yang dapat digunakan untuk mengeringkan berbagai jenis bahan baku makanan. Alat pengering ini dirancang dengan tipe paralel flow tray dimana udara panas yang dihasilkan akan disirkulasikan sejajar dengan permukaan rak pengering dan bekerja menggunakan sumber energi listrik. Penelitian ini bertujuan untuk memodifikasi pengering tray dryer dengan penambahan insulator dan mengetahui konsumsi energi alat pengering tray dryer pada pengeringan kunyit. Parameter pengujian uji kinerja alat tanpa bahan meliputi distribusi suhu, kelembaban relatif dan kecepatan aliran udara dan untuk perhitungan konsumsi energi meliputi penggunaan energi listrik, perhitungan energi thermal, energi mengeringkan bahan, energi untuk menguapkan air bahan, efisiensi pengeringan, energi kipas dan kehilangan energi melalui cerobong. Pada pengujian pengering tray dryer suhu yang digunakan adalah 55°C. Hasil penelitian menunjukkan bahwa secara fungsional dan struktural alat pengering tray dryer setelah dimodifikasi dengan melapisi dinding luar ruang pengering dapat beroperasi dengan baik, proses pengeringan lebih cepat dan energi yang digunakan juga sedikit dibandingkan dengan sebelum dimodifikasi. Konsumsi energi listrik pada alat pengering tray dryer setelah dimodifikasi pada saat proses pengeringan dengan suhu 35oC selama 6,5 jam sebesar 35,33 kWh (127,2 MJ), pada suhu 45oC sebesar 24,26 kWh (88,06 MJ) dengan lamanya pengeringan selama 4,5 jam dan suhu 55oC sebesar 18,89 kWh (68,01 MJ) dengan lama pengeringan selama 3,5 jam, hal ii disebabkan lama pengeringan merupakan salah satu faktor yang menyebabkan besar kecilnya konsumsi energi listrik. Konsumsi energi thermal selama proses pengeringan dengan suhu 35°C adalah sebesar 17,53 MJ, suhu 45°C sebesar 19,54 MJ dan suhu 55°C sebesar 21,34 MJ. Berdasarkan hasil kalkulasi antara energi listrik dan energi thermal didapatkan efisiensi pengeringan pada suhu 35°C sebesar 27,80%, suhu 45°C sebesar 22,2% dan suhu 55°C sebesar 31,4%.Modification Of Tray Dryer With InsulatorAbstract. Tray Dryer is a type of dryer or cabinet dryer that can be used to dry various types of food raw materials. This dryer is designed with a parallel flow tray type where the hot air generated will be circulated parallel to the surface of the drying rack and work using an electric energy source. This study aims to modify the tray dryer with the addition of an insulator and determine the energy consumption of dryer dryers in turmeric drying. The test parameters of the performance test of equipment without material include temperature distribution, relative humidity and air flow velocity and for the calculation of energy consumption including the use of electrical energy, thermal energy calculation, energy drying material, energy to evaporate material water, drying efficiency, fan energy and energy loss through chimney. In testing the tray dryer dryer the temperature used is 55 ° C. The results showed that functionally and structurally the tray dryer after being modified by covering the outer walls of the drying chamber could operate well, the drying process was faster and the energy used was also less compared to before it was modified. Electric energy consumption in the tray dryer after being modified during the drying process with a temperature of 35oC for 6.5 hours amounted to 35.33 kWh (127.2 MJ), at a temperature of 45oC of 24.26 kWh (88.06 MJ) with a duration drying for 4.5 hours and a temperature of 55oC of 18.89 kWh (68.01 MJ) with a drying time of 3.5 hours, this is due to the length of drying is one of the factors causing the size of the electrical energy consumption. The consumption of thermal energy during the drying process with a temperature of 35 ° C is 17.53 MJ, a temperature of 45 ° C is 19.54 MJ and a temperature of 55 ° C is 21.34 MJ. Based on the results of calculations between electrical energy and thermal energy obtained drying efficiency at a temperature of 35 ° C at 27.80%, a temperature of 45 ° C at 22.2% and a temperature of 55 ° C at 31.4%


2022 ◽  
Vol 215 ◽  
pp. 49-66
Author(s):  
Ángel H. Moreno ◽  
Ángel Javier Aguirre ◽  
Rafael Hernández Maqueda ◽  
Geovanny Jiménez Jiménez ◽  
Carlos Torres Miño

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo

Drying characteristics of persimmon, cv. “Rojo Brillante”, slabs were experimentally determined in a hot air convective drier at drying temperatures of 45, 50, 55, 60, and 65 °C at a fixed air velocity of 2.3 m/s. It was observed that the drying temperature affected the drying time, shrinkage, and colour. Four empirical mathematical models namely, Enderson and Pabis, Page, Logarithmic, and Two term, were evaluated in order to deeply understand the drying process (moisture ratio). The Page model described the best representation of the experimental drying data at all investigated temperatures (45, 50, 55, 60, 65 °C). According to the evaluation of the shrinkage models, the Quadratic model provided the best representation of the volumetric shrinkage of persimmons as a function of moisture content. Overall, higher drying temperature (65 °C) improved the colour retention of dried persimmon slabs.


2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Libo Zhang ◽  
Wenqian Guo ◽  
Tu Hu ◽  
Jing Li ◽  
Jinhui Peng ◽  
...  

AbstractThe process of microwave drying ammonium tetramolybdate is studied, and the process variables of drying time, drying temperature and material thickness are considered. Experiences of microwave drying ammonium tetramolybdate have been optimized using response surface methodology (RSM) technique and a CCD design. Effects of each factor and their interactions are researched, and a quadratic polynomial model for dehydration ratio is established. As can be seen from the ANOVA, the effects of the three process variables are found to be significant in the model, and the empirical model is fit and reliable to check the dehydration ratio of ammonium tetramolybdate. The optimum conditions for drying using microwave heating are found as follows: drying temperature 67°C, drying time 9.5 min and material thickness 15 mm. The optimum dehydration ratio is 79.82% and the last molybdenum content is not <56.3%, with the relatively error of 0.64%, which indicates the success of the process optimization experiments. This research has important significance to offer optimum conditions for industrial production.


Author(s):  
Magesh Ganesh Pillai ◽  
Iyyasamy Regupathi ◽  
Lima Rose Miranda ◽  
Thanapalan Murugesan

The drying characteristics of plaster of paris (POP) under microwave conditions at different microwave power input, initial moisture content, sample thickness and drying time were studied. Further the experimental data on moisture ratio of POP for different operating conditions were obtained and calculations were made using nine basic drying model equations. The appropriate model with modified constants and coefficients to represent the drying kinetics of POP was found through the analysis of the statistical analysis. The effective moisture diffusivity of the drying process was also computed for different experimental conditions and a relationship between the drying rate constant and the effective moisture diffusivity was obtained. The energy consumption for microwave drying of plaster of paris at different experimental conditions were also computed.


2013 ◽  
Vol 838-841 ◽  
pp. 2643-2647
Author(s):  
Jin Ping Li ◽  
Meng Yao Li ◽  
Wen Yao ◽  
Ni Wang

Combination of oven and microwave and only oven are two ways to study municipal sludge,and it investigates whether different size, microwave drying pretreatment, pretreatment time and oven temperature characteristics have effect on drying characteristics. The results shows that: using microwave to dry sludge need short time, the drying rate is fast, combination of oven and microwave has higher drying rate and lower energy consumption than only oven.


2020 ◽  
Vol 12 (2) ◽  
pp. 115-130
Author(s):  
Leidy Laura Cruz-de la Cruz ◽  
Teodoro Espinosa-Solares ◽  
Miguel Angel Aguilar-Méndez ◽  
Diana Guerra-Ramírez ◽  
Guadalupe Hernández-Eugenio

Introduction: The drying of nopal offers an alternative for their preservation, storage, handling and consumption. Objective: The effects of microwave drying on the microstructural characteristics of nopal and their thermodynamic properties at the food-water interface were evaluated. Methodology: Nopal cladodes were microwave-dried by applying powers of 75 and 158 kW∙kg-1. Microstructure of the samples was evaluated by Scanning Electron Microscope. Adsorption isotherms were determined at temperatures of 10, 20, 30 and 40 °C. Net isosteric heat (q-st) was calculated using the Clausius-Clapeyron equation and the Peleg model. Results: Samples dehydrated at 75 kW∙kg-1 showed greater preservation of their internal and external structure. When applying a higher power (158 kW∙kg-1), greater damage was observed in the microstructure of the material. Type III adsorption isotherm curves were obtained according to the Brunauer classification. The q-st of the dehydrated nopal was 7.51 kJ∙mol-1 for a moisture content of 0.05 kgH2O∙kg-1. Limitations of the study: The results obtained are valid only for microwave drying by applying powers of 75 and 158 kW∙kg-1. Originality: This work proposes the microwave drying of nopal as an alternative method that reduces drying time and allows the preservation of the material’s structural properties. Conclusions: The power applied in the microwave drying of nopal had a direct impact on the microstructure of the samples. The use of a power of 75 kW∙kg-1 was the best drying condition to preserve the structures constituting the cladodes.


2019 ◽  
Vol 8 (2) ◽  
pp. 249
Author(s):  
I Kadek Wirawan ◽  
Pande Ketut Diah Kencana ◽  
I Made Supartha Utama

Penelitian ini bertujuan untuk mengetahui pengaruh suhu dan waktu pengeringan terhadap karakteristik kimia dan sensorik teh daun bambu Tabah. Penelitian ini dirancang menggunakan Rancangan Acak Lengkap (RAL) dengan dua faktor, yaitu faktor suhu pengeringan (50o C dan 60o C) dan faktor waktu pengeringan (1 jam, 2 jam, dan 3 jam). Perlakuan diulang tiga kali untuk mendapatkan 18 unit percobaan. Parameter yang diamati adalah kadar air, pH, total asam, total fenol, dan organoleptik. Hasil penelitian menunjukkan bahwa interaksi suhu dan lama pengeringan daun teh bambu Tabah memiliki pengaruh berbeda nyata terhadap kadar air, pH, total asam, total fenol, warna, penerimaan keseluruhan, tetapi tidak memiliki pengaruh yang berbeda nyata terhadap aroma dan rasa, dengan perlakuan terbaik ini, kadar air, pH, asam total, fenol total, warna, aroma, rasa dan penerimaan keseluruhan ditemukan kadar air 6,881%, pH 6,6, total asam 0, 73%, total fenol 84,01mg / 100g, warna 4,33, aroma 4,40, rasa 3,93, dan penerimaan keseluruhan 4,07.   This study aimd to determine the effect of temperature and drying time on the chemical and sensory characteristics of Tabah bamboo leaf tea. This study was designed using a Completely Randomized Design (CRD) with two factors, namely the drying temperature factor (50oC and 60oC) and the drying time factor (1 hour, 2 hours, and 3 hours). The treatment was repeated three times to obtain 18 experimental units. The parameters observed were water content, pH, total acid, total phenol, color, aroma, taste, and overall acceptance tested organoleptically. The results showed that the interaction of temperature and duration of drying of Tabah bamboo tea leaves had significantly different effects on water content, pH, total acid, total phenol, color, overall reception, but did not have a significantly different effect on aroma and taste. with this combained best treatment, the water content, pH, total acid, total phenol, color, aroma, taste and overall acceptance were found water content 6,881 %, pH 6,6, total acid 0, 73%, total phenol 84,01mg / 100g,color 4,33, aroma 4.40, taste 3,93, and overall acceptance 4,07.


Food Research ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 389-395
Author(s):  
Rahmawati Rahmawati ◽  
D. Hunaefi ◽  
I. Basriman ◽  
Dede Saputra ◽  
A.A. Apriliani ◽  
...  

The study was conducted to obtain an optimal combination of time and temperature of the drying process of indigenous cocktail yeast mold culture using RSM. The cocktail yeast mold culture was dried using an oven. The cocktail cultures contain Penicillium citrinum, Aspergillus niger, Acremonium strictum, and Candida famata, namely AC (Amylolytic Culture). The Response Surface Methods (RSM) with Design-Expert® 7.00 software, namely Mixture design with D-optimal was performed. The drying time was between 24- 48 hrs and the drying temperature was between 40-50oC. The total of 16 formulas of the combination of drying time and temperature for processing the dried cultures were produced by RSM. The response chosen was total viability of mold and yeast, water content, water activity, and pH. The result of optimization and verification was obtained by the model: pH (AC) = -0.058A - 1.56 x 10-003B + 7.13, where A = drying temperature ( oC), B = drying time (hr). The AC optimization was achieved at a combination of drying temperatures and time of 50oC for 48 hrs. Desirability values were 0.729. The optimum formula for AC has viability of total yeast mold of 7.39 x 106 CFU/g, moisture content of 5.62%, aw 0.303, and pH 4.18.


2020 ◽  
Vol 10 (18) ◽  
pp. 6309
Author(s):  
Yousef Abbaspour-Gilandeh ◽  
Mohammad Kaveh ◽  
Muhammad Aziz

In this study, the drying time, effective moisture diffusivity (Deff), specific energy consumption (SEC), and quality (color, shrinkage, and rehydration) of the ultrasound-pretreated (US) carrot slices were compared when dried by hot air drying (HD), microwave drying (MWD), infrared drying (INFD), and hybrid methods of MW–HD and INF–HD. Five mathematical models were considered to describe the drying kinetics in the carrots. The results show that US+MW–HD and INFD were the fastest and the slowest drying techniques compared to the HD technique with a 73% and 23% drying time reduction, respectively. The Deff ranged from 7.12 × 10−9 to 2.78 × 10−8 m2/s. The highest and lowest SECs were 297.29 ± 11.21 and 23.75 ± 2.22 MJ/kg which were observed in the HD and US+MWD, respectively. The color variation indices indicated that the best sample in terms of color stability was the one dried by US+MW–HD with the color variation of 11.02 ± 0.27. The lowest and highest shrinkage values were also observed in the samples dried by US+MWD and HD (31.8 ± 1.1% and 62.23 ± 1.77%), respectively. Samples dried by US+MWD and HD possessed the highest and lowest rehydration, respectively. Although the carrot slices dried at a higher pace by US+MW–HD (compared to US+MWD), the shrinkage and SEC of the samples dried by US+MWD were significantly lower than the US+MW–HD (p < 0.05). Therefore, it can be concluded that the application of the US+MWD method can be considered as a proper alternative for drying the carrot slices when compared to the HD, MWD, INFD, and hybrid methods.


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