Degradation Kinetics of Bioactive Compounds and Antioxidant Activity of Pomegranate Arils during the Drying Process

2014 ◽  
Vol 10 (4) ◽  
pp. 839-848 ◽  
Author(s):  
Mehmet Başlar ◽  
Salih Karasu ◽  
Mahmut Kiliçli ◽  
Ahmet Abdullah Us ◽  
Osman Sağdiç

Abstract In this study, the drying kinetics of pomegranate arils, the degradation kinetics of some bioactive compounds, and changes in color values during the drying process were investigated. The drying process was performed by a forced air circulating oven at 55, 65, and 75°C. Drying times were calculated to be 1,020, 520, and 330 min, respectively. Effective moisture diffusivity values ranged from 5.39×10−11 to 1.70×10−10 m2 s−1 and increased with increases in temperature. Six different thin-layer drying models were applied to evaluate the goodness of the model. The degradation rate of bioactive compounds increased at higher temperatures; however, remaining amounts of phenolic, anthocyanin, and flavonoid compounds after drying were higher in samples dried at 75°C. The highest antioxidant capacity value was observed in the pomegranate arils dried at 75°C. While the L* values of pomegranate arils decreased after the drying process, the a* values increased.

2021 ◽  
Vol 8 (2) ◽  
pp. 53-62
Author(s):  
Hendri Syah ◽  
Armansyah Halomoan Tambunan ◽  
Edy Hartulistiyoso ◽  
Lamhot Parulian Manalu

The objectives of this study were to determine a suitable thin layer drying model to describe the drying kinetics of Guazuma ulmifolia leaves and determine the mass transfer parameters of Guazuma ulmifolia leaves. The drying of Guazuma ulmifolia leaves was conducted in a laboratory scale dryer with various temperature (40oC, 50oC, and 60oC) and relative humidity (30%, 40%, 50% and 60%). Five drying models, namely, Newton, Henderson and Pabis, Page, Midilli-Kucuk, and Verma et al. were fitted to the drying data. The drying curve of guazuma leaves did not show a constant drying period during the drying period. The models suitability were compared base on coefficient of determination (R2), root square mean errors (RSME), and reduced mean square of deviation (X2). It was found that, among the models evaluated, the Midilli and Kucuk model is the best to describe the drying kinetics of Guazuma ulmifolia leaves. The effective moisture diffusivity was found to be in the range of 10-13 – 10-12 m2/s and the convective mass transfer coefficient was in the range of 10-9 – 10-10 m/s. The activation energy value was found to be 89.21 kJ/mol.


2013 ◽  
Vol 371 ◽  
pp. 323-327
Author(s):  
Miloš Vasić ◽  
Zagorka Radojević

Drying results, determined on samples made of masonry clay from the locality "Banatski Karlovac", are presented in this study. Experimental investigations were carried out in a laboratory recirculation dryer in which drying parameters (humidity, temperature, and velocity) could be programmed, controlled and monitored during drying process. Several mathematical models were used for drying process modelling. New semi-theoretical thin layer drying model, for heavy clay products, was developed and presented in this study. It represents a modification of Page's and logarithm's thin layer drying models. Results presented in this study have shown that new thin layer drying model describes and correlates the best experimentally determined drying process.


2017 ◽  
Vol 7 (2) ◽  
pp. 14 ◽  
Author(s):  
Luqman Ebow Ibn Daud ◽  
Isaac Nyambe Simate

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.


2019 ◽  
Vol 37 (No. 2) ◽  
pp. 128-134
Author(s):  
Osman Yağız Turan ◽  
Ebru Fıratlıgil

Fruit and vegetable dehydration has been extensively studied for the improvement of food preservation. Effects of drying temperature on the drying kinetics of thyme were investigated and a suitable drying model was obtained to describe the drying process. Drying behaviour of thyme leaves at temperatures of 50, 60, 70 and 80°C was determined by using a conventional drying oven, and moisture ratio and drying rates were calculated. Four different thin layer drying models, namely Lewis, Henderson and Pabis, Page, and logarithmic models, were used to fit the experimental moisture ratio data. Three statistical parameters: coefficient of determination (R<sup>2</sup>), chi-square (χ<sup>2</sup>) and root mean square error (RMSE) were used to compare the goodness of fit of the drying models. Logarithmic model and Page model give the best description of the drying process kinetics of thyme leaves by comparing the experimental values and predicted values.


2019 ◽  
Vol 25 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Azmi Kipcak ◽  
İbrahim Doymaz ◽  
Emek Moroydor-Derun

As an alternative to fish and beef, blue mussels (Mytilus edulis) can be consumed due to their high protein content. In this study, the drying kinetics and quality changes (cook loss, area shrinkage and colour change) in whole blue mussels were investigated with several infrared power levels between 88?146 W. Various thin-layer drying models were applied to the blue mussel and the Midilli et al., model best fits the experimental data (R2: 0.999150?0.999750, ?2: 0.000104?0.000030, RMSE: 0.008309?0.004797). The effective moisture diffusivity was determined to be between 4.24?10-9 and 1.10?10-8 m2/s. The activation energy was found to be 20.85 kW/kg. The cook loss and area shrinkage increased with increasing power level and drying time. Most cook loss (30%) and area shrinkage (30%) were obtained between 15-23 min and 8-20 min of drying time, respectively. The colour change was slightly affected by the change in infrared power level.


Author(s):  
Narjes Malekjani ◽  
Zahra Emam-Djomeh ◽  
Seyed Hassan Hashemabadi ◽  
Gholam Reza Askari

AbstractThe effects of microwave-convective drying as an efficient drying method, on drying kinetics of hazelnuts were studied. Drying experiments were conducted at three temperature (40, 50 and 60°C) and microwave power (0, 450 and 900 W) levels. The moisture ratio and the temperature of the hazelnuts were recorded during the drying. The results showed that microwave power had a more dominant effect than drying air temperature. Mathematical modeling was performed in order to predict the moisture changes during drying process. It was concluded that two term and Midilli et al. models were the best models to predict the drying kinetics of hazelnut in different conditions. The effective moisture diffusivities varied from 3.80327×10‒8to 1.71233×10‒6m2/s and had an increasing polynomial relationship with temperature and microwave power. The activation energy was also between 15.61675 and 41.0053 kJ/mol with a second-order relationship with microwave power.


Author(s):  
Raj Kumar Goyal ◽  
Mujjeb O ◽  
Vinod Kumar Bhargava

In this study, the drying kinetics of apple (control, blanching and blanching in 1% potassium meta bisulphate) in a tunnel dryer was studied at 50, 60, and 70°C air temperatures. The drying of apple slices occurred in a falling rate period. It was found that treated apple slices dried faster. Six thin layer-drying models were fitted to the experimental moisture ratio. Among the mathematical models evaluated, the logarithmic model satisfactorily described the drying behaviour of apple slices with high r2 values. The effective moisture diffusivity (Deff) of apple slices increased as the drying air temperature increased. The Deff values were higher for the treated samples than for the control.


2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Akinjide A Akinola ◽  
Stanley N. Ezeorah

 This study aims to investigate the drying characteristics of cassava, yam, and potato slices using a laboratory scale batch Refractance Window™ (RW) dryer. The experimental dryer was constructed by modifying a laboratory water bath. The bath was covered with a transparent Polyethylene terephthalate (PET) plastic film held in-place with angled edges. The cassava, yam, and potato slices were dried on the Refractance WindowTM dryer, and the variation of the moisture content of the slices during the drying process was measured. The water temperature beneath the plastic film was maintained at 60oC. The dehydration data were fitted to thin-layer drying models. Regression analysis suggested that the Haghi and Ghanadzadeh model best describes the dehydration behaviour for the 3 mm thick slices for the cassava, yam, and potato tubers. The coefficient of determination (R2) values of 0.999, 0.998, and 0.998 for the cassava, yam, and potato slices respectively were reported in all the models studied. The drying curves, the drying rate curves, and the Krischer curves, from the experimental drying data, was plotted. Observations indicate that the cassava, yams, and potatoes slices dried to below 0.11 g water/g-solid moisture content in about 150 min. This study was performed to facilitate the understanding of the design, modelling, and operations of a continuously operating RW dryer. Keywords: Refractance Window Drying, Thin Layer Drying Models, Yams, Cassava, Potatoes.


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