Heat Transfer Characteristics and Kinetics of Camellia oleifera Seeds During Hot-Air Drying

2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Dan Huang ◽  
Yuchao Tao ◽  
Wei Li ◽  
S. A. Sherif ◽  
Xiaohong Tang
Keyword(s):  
Heat Transfer ◽  
Camellia Oleifera ◽  
Heat Transfer Characteristics ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Hot Air ◽  
Rate Period ◽  
Kinetics Of

Abstract The heat transfer characteristics and kinetics of Camellia oleifera seeds under hot-air drying were investigated at different temperatures (40, 60, and 80 °C) and loading densities (0.92, 1.22, and 1.52 g/cm2) with a constant air velocity of 1 m/s. Twelve common drying kinetic models were selected to fit the experimental data. The most suitable model was chosen to describe the hot-air drying process of C. oleifera seeds and help in its optimization. The results showed that the drying temperature has a significant influence on the hot-air drying characteristics of C. oleifera seeds. As the drying air temperature increases, the drying time decreases. The effect of the loading density on the drying characteristics of C. oleifera seeds is much smaller than that of temperature. With the increase in the loading density, the drying time slightly increases. The hot-air drying curve of C. oleifera seeds consists of a very short acceleration rate period at the beginning and a long falling rate period, indicating that the drying of C. oleifera seeds is mainly controlled by the diffusion of moisture inside the material. An effective moisture diffusion coefficient of C. oleifera seeds was estimated to range from 0.81256 × 10−9 to 3.28496 × 10−9 m2/s within the temperature range studied. The average activation energy was 28.27979 kJ/mol. The logarithmic model was found to be the best model to describe the kinetics of hot-air drying of C. oleifera seeds.

scholarly journals Influence of Different Hot Air Drying Temperatures on Drying Kinetics, Shrinkage, and Colour of Persimmon Slices

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo
Keyword(s):  
Moisture Content ◽  
Quadratic Model ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Hot Air

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.

scholarly journals Hot air drying characteristics and nutrients of apricot armeniaca vulgaris lam pretreated with Radio Frequency(RF)

2018 ◽  
Author(s):  
X.L. Huang ◽  
M.C. Peng ◽  
J.X. Liu ◽  
Y. Lei ◽  
X.J. Yang ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Drying Rate ◽  
Hot Air Drying ◽  
Air Drying ◽  
Drying Characteristics ◽  
Hot Air ◽  
Rate Period ◽  
Pretreatment Time

Apricot pretreated with RF and then dried with convective hot air at 65℃, 3.0m/s in this research. RF pretreatment time of 20, 30, 40 and 50min were chosen. Results showed that, there is only falling rate period during apricot hot air drying, and the drying rate of apricot is improved significantly; Herdenson and Pabis model is suitable for apricot hot air drying; retentions of flavonoids, polyphenols and Vc in dried apricot were higher than those of fresh apricot; when RF treating time was chosen 30mins, nutrients retentions of Vc, flavonoid and polyphenols were 0.9543mg/100g, 5.4089mg/100g and 7.3382mg/100g, separately.   Keywords: apricot fruit, hot air drying, drying rate, nutrients, radio frequency 

scholarly journals Effect of Freeze-Thaw Cycles on Juice Properties, Volatile Compounds and Hot-Air Drying Kinetics of Blueberry

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2362
Author(s):  
Lin Zhu ◽  
Xianrui Liang ◽  
Yushuang Lu ◽  
Shiyi Tian ◽  
Jie Chen ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Drying Kinetics ◽  
Soluble Solids ◽  
Hot Air Drying ◽  
Fresh Sample ◽  
Drying Time ◽  
Air Drying ◽  
Freeze Thaw ◽  
Hot Air ◽  
Kinetics Of

This paper studied the effects of freeze-thaw (FT) cycles on the juice properties and aroma profiles, and the hot-air drying kinetics of frozen blueberry. After FT treatment, the juice yield increased while pH and total soluble solids of the juice keep unchanged. The total anthocyanins contents and DPPH antioxidant activities of the juice decreased by FT treatments. The electronic nose shows that FT treatments significantly change the aroma profiles of the juice. The four main volatile substances in the fresh juice are (E)-2-hexenal, α-terpineol, hexanal and linalyl formate, which account for 48.5 ± 0.1%, 17.6 ± 0.2%, 14.0 ± 1.5% and 7.8 ± 2.7% of relative proportions based on total ion chromatogram (TIC) peak areas. In the FT-treated samples, the amount of (E)-2-hexenal and hexanal decreased significantly while α-terpineol and linalyl formate remained almost unchanged. Repeated FT cycles increased the ethanol content and destroyed the original green leafy flavor. Finally, the drying kinetics of FT-treated blueberries was tested. One FT treatment can shorten the drying time by about 30% to achieve the same water content. The Deff values of the FT-treated sample are similar, which are about twice as large as the value of the fresh sample. The results will be beneficial for the processing of frozen blueberry into juice or dried fruits.

scholarly journals Comparative Evaluation of Drying Kinetics of Carrot Slices in Hot air and Microwave Drying

2021 ◽  
Vol 10 (4) ◽  
pp. 242-248
Author(s):  
Gitanjali Behera ◽  
◽  
Mitali Madhumita ◽  
J. Aishwarya Aishwarya ◽  
V. Gayathri ◽  
...  
Keyword(s):  
Microwave Drying ◽  
Quality Analysis ◽  
Rehydration Ratio ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air ◽  
Sensory Score ◽  
Kinetics Of ◽  
Different Thickness

Carrot is most the important vegetable grown throughout the World. It is also a very good source of βcarotene, α-carotene and zeaxanthin. The post-harvest losses because of having high moisture content limit the utilization of carrot. In the present investigation, the comparative analysis was done between hot air drying and microwave drying for different thickness of carrot slices. The quality analysis for both the dried products was performed and compared. The drying time was varied between 3.5 h to 10 h for try drying whereas for microwave drying it was 240 sec to 681.6 sec. The drying time reduces drastically in case of microwave drying in comparison to hot air drying. The moisture ratio for both dried techniques was found to decreasing with an increase in drying time. The microwave dried samples showed a better rehydration ratio than the hot air dried sample. Also, the dehydration ratio of dried carrot sample using microwave drying was found to be lowest compared to the hot air dried sample. The microwave dried carrot slices showed a better sensory score in terms of colour and shape than hot air dried sample. Therefore, microwave drying may be recommended to dry carrot slices to have better energy efficiencies

scholarly journals Modeling of hot air drying of coconut residue

2018 ◽  
Vol 192 ◽  
pp. 03061
Author(s):  
Pattawee Wutthigarn ◽  
Jeerayut Hongwiangjan ◽  
Jiraporn Sripinyowanich Jongyingcharoen
Keyword(s):  
Exponential Model ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Polynomial Type ◽  
Hot Air ◽  
Best Fitting ◽  
Drying Models

In this study, the effect of drying temperature (50-110°C) on hot air drying characteristics of coconut residue was investigated. The drying time and drying rate (DR) were in the ranges of 540-100 min and 0.0048-0.0182 g water/g dry matter·min at the drying temperature of 50-110°C, respectively. Six drying models (Lewis, Page, Henderson and Pabis, Logarithmic, Midilli et al, and linear-plus-exponential model) were used to determine the change in moisture ratio (MR) with drying time. The linear-plus-exponential model provided best fitting of the predicted MR to the experimental MR with the highest average R2 of 0.9985 and the lowest RMSE of 0.01463. The variation of drying temperature with the constants and coefficient of the model was polynomial type. The generalized linear-plus-exponential model as a function of drying temperature gave best result of prediction of MR with the R2 of 0.9709.

scholarly journals Empirical Modeling of Hot Air-Drying Kinetics of Horseradish Dehydration

2020 ◽  
Vol 4 (1) ◽  
pp. 44
Author(s):  
Mukesh Guragain ◽  
Pranabendu Mitra
Keyword(s):  
Moisture Content ◽  
Empirical Models ◽  
Drying Kinetics ◽  
Hot Air Drying ◽  
Air Drying ◽  
Drying Temperature ◽  
Hot Air ◽  
Rate Period ◽  
Drying Conditions ◽  
Kinetics Of

The preservation of perishable horseradish crop is essential to increase the shelf-life and supply year-round. Hot air-drying method is commercially viable for preserving fruits and vegetables. However, drying conditions such as drying temperature affect the drying kinetic and the final quality of dried products. It is necessary to understand how drying temperature and blanching affect the drying kinetics of horseradish for the prediction of the right drying conditions. The objective of this study was to investigate the hot air-drying kinetics by fitting commonly used five empirical models to establish right hot air-drying conditions for drying of horseradish. The unblanched (control, C) and blanched (B) horseradish slices were dried at 50, 70 and 85℃ until reaching to an equilibrium moisture content (db). The moisture reduction data were collected at certain intervals and the moisture content data were converted to moisture ratio (MR). The MR data were used to predict the drying kinetics of horseradish drying using five empirical models. The results indicated that drying kinetics followed the constant drying rate period and falling rate period for all three drying temperatures. The five tested models were able to predict the drying kinetics with R2 (0.96-0.99) and RMSE (0.01-0.06) depending on the models and blanching. However, diffusion approach model was the best fitted model securing the highest R2 and the lowest RMSE. The findings of this research are expected to be significantly important for horseradish drying effectively.

scholarly journals Modelling the Thin-Layer Drying Kinetics of Marinated Beef during Infrared-Assisted Hot Air Processing of Biltong

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Francis C. Muga ◽  
Moses O. Marenya ◽  
Tilahun S. Workneh
Keyword(s):  
Drying Kinetics ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Emitter Temperature ◽  
The Core ◽  
Hot Air ◽  
Thin Layer Drying ◽  
Rate Period ◽  
Kinetics Of

Biltong is a dried meat product that is widely consumed in South Africa. The marinated meat is traditionally dried under ambient winter conditions while commercial biltong producers use hot air driers. Hot air drying is time-consuming and energy-intensive. A combined infrared and hot air drying (IRHAD) is an alternative method of drying meat during biltong processing. The aim of this study was to establish the effect of the infrared (IR) power, the temperature, and velocity of the drying air on the drying kinetics of marinated beef and subsequently select the best thin-layer drying model for IRHAD during biltong processing. Marinated beef samples were dried at IR power levels of 500, 750, and 1000 W; drying air temperatures of 30, 35, and 40°C; and air velocity of 1.5 and 2.5 m∙s-1. Results indicate that increasing the IR power and the drying air temperature increased the IR emitter temperature and the core temperature of the marinated beef sample. Consequently, increasing the drying rate thus reduced drying time. The air velocity had an inverse relationship with the IR emitter temperature, the core temperature of the marinated beef sample, and the drying rate. The drying process was characterised by a rising rate period in the first half an hour, followed by a falling rate period which implies that moisture transport occurred partly by surface evaporation and predominantly by diffusion. The effective moisture diffusivity ranged from 4.560 × 10 − 10 to 13.7 × 10 − 10   m 2 ∙ s − 1 , while, the activation energy ranged between 40.97 and 59.16 kJ∙mol-1. The IRHAD of marinated beef during its processing to biltong was best described by the two-term model since it had the highest R 2 (0.9982-0.9993) and the lowest RMSE (0.0062-0.0099). The power level of the IR emitter of 1000 W combined with a drying air temperature and velocity of 40°C and 1.5 m∙s-1, respectively, showed the highest improvement in the drying kinetics and the lowest drying time of 5.61 ± 0.35 hours; hence, it is recommended as a possible drying alternative for the processing of biltong.

scholarly journals Ultrasound-Enhanced Hot Air Drying of Germinated Highland Barley Seeds: Drying Characteristics, Microstructure, and Bioactive Profile

2019 ◽  
Vol 1 (4) ◽  
pp. 496-510
Author(s):  
Yan Song ◽  
Yang Tao ◽  
Xiaoyu Zhu ◽  
Yongbin Han ◽  
Pau Loke Show ◽  
...  
Keyword(s):  
Phenolic Content ◽  
Original Structure ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Organic Selenium ◽  
Hot Air ◽  
Highland Barley

The effects of ultrasound-enhanced hot air drying on the drying characteristics, microstructure and bioactive profile of germinated highland barley seeds (GHB) were studied. GHB was dried by hot air at 55 °C and 70 °C and ultrasonic intensities of 125.1 W/dm2 and 180.2 W/dm2, respectively. The results showed that when the drying temperature was 55 °C or 70 °C, the sonicated groups could shorten the drying time by 17.4–26.1% or 18.8–31.3%, respectively. Ultrasound drying at 125.1 W/dm2 and 55 °C could mostly increase the content of organic selenium and the rehydration rate, improve the color and maintain the original structure of GHB. Compared with hot air drying alone, the phenolic content did not increase due to ultrasound-enhanced hot air drying. Therefore, drying at an ultrasonic intensity of 125.1 W/dm2 and a temperature of 55 °C could effectively shorten the drying time, and enhance the quality of GHB.

scholarly journals Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 202
Author(s):  
Ivan Pavkov ◽  
Milivoj Radojčin ◽  
Zoran Stamenković ◽  
Krstan Kešelj ◽  
Urszula Tylewicz ◽  
...  
Keyword(s):  
Activation Energy ◽  
Osmotic Dehydration ◽  
Effective Diffusivity ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air ◽  
Kinetics Of

This study aimed to determine the effects of osmotic dehydration on the kinetics of hot air drying of apricot halves under conditions that were similar to the industrial ones. The osmotic process was performed in a sucrose solution at 40 and 60 °C and concentrations of 50% and 65%. As expected increased temperatures and concentrations of the solution resulted in increased water loss, solid gain and shrinkage. The kinetics of osmotic dehydration were well described by the Peleg model. The effective diffusivity of water 5.50–7.387 × 10−9 m2/s and solute 8.315 × 10−10–1.113 × 10−9 m2/s was calculated for osmotic dehydration. Hot air drying was carried out at 40, 50, and 60 °C with air flow velocities of 1.0 m/s and 1.5 m/s. The drying time shortened with higher temperature and air velocity. The calculated effective diffusion of water was from 3.002 × 10−10 m2/s to 1.970 × 10−9 m2/s. The activation energy was sensitive to selected air temperatures, so greater air velocity resulted in greater activation energy: 46.379–51.514 kJ/mol, and with the osmotic pretreatment, it decreased to 35.216–46.469 kJ/mol. Osmotic dehydration reduced the effective diffusivity of water during the hot air drying process. It also resulted in smaller shrinkage of apricot halves in the hot air drying process.

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