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.

Effects of drying methods on color retention and chlorophyll of celery (ApiumgraveolensL.), spinach (Spinacia oleraceaL.), Malabar spinach (Basella albaL.)

2020 ◽  
pp. 53-61
Author(s):  
Dat Q Tran
Keyword(s):  
Microwave Drying ◽  
Drying Methods ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Color Retention ◽  
Hot Air ◽  
Drying Techniques ◽  
Dried Vegetables

Dried vegetables are considered convenient for storage, transportation and preservation. The different drying techniques could influence the quality of resulting products. This study aimed to evaluate the effects of three distinguish drying methods as hot-air drying, foam-mat drying and microwave drying on the color retention and chlorophyll of green vegetables powder. Fresh spinach(Spinacia oleraceaL.), celery (Apium graveolensL.), Malabar spinach (Basella albaL.) were dried by different methods: hot air at 60oC, foam-mat at 60oC and microwave at 270 W until the samples reached approximately 9% of moisture content (wb). The drying time of the dried samples by microwave, foam-mat and hot-air method were 60, 210 and 240 min, respectively. Foam-mat dried vegetables were found to have the best quality in terms of color and the residual chlorophyll content. The findings suggest that foam-mat drying is promising in dried vegetable processing

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.

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 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 Hybrid and intermittent drying of carrot (Daucus carota var. Nantes)

2018 ◽  
Author(s):  
Dominik Mierzwa ◽  
Justyna Szadzińska ◽  
Krzysztof Bukowski
Keyword(s):  
Mass Transfer ◽  
Convective Drying ◽  
Drying Rate ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air ◽  
Intermittent Mode ◽  
Airborne Ultrasound

A combination of high power airborne ultrasound and microwaves in hot air drying was developed to investigate the effect of intermittent mode on process effectiveness and quality of carrot. The drying experiments were carried out in an innovative hybrid dryer. The course of moisture ratio, drying rate, specific energy and water consumption, colour, water activity and shrinkage were discussed. The results showed that intermittent ultrasound and microwaves in convective drying accelerate the heat and mass transfer, leading to shorter drying time and faster drying rate. It was found that hybrid-intermittent drying can improve the energy efficiency and product quality. Keywords: intermittent drying; ultrasound; microwaves; energy; shrinkage

scholarly journals Examination of physical properties of final product and drying properties of combined (convective pre-drying and freeze finish-drying) dehydration method

2014 ◽  
pp. 5-12
Author(s):  
Tamás Antal
Keyword(s):  
Freeze Drying ◽  
Operating Conditions ◽  
Small Scale ◽  
Case Hardening ◽  
Degree Polynomial ◽  
Hot Air Drying ◽  
Drying Time ◽  
Drying Characteristics ◽  
Hot Air ◽  
Drying Properties

In this study, the effects of freeze drying (FD), hot-air drying (HAD) and combined drying (HAD-FD) on drying characteristics, energy uptake, texture, rehydration and color of carrot were investigated. Results showed that HAD-FD significantly improved the drying time compared with FD under the same operating conditions, and the HAD-FD can reduce the total cost of dehydration. The drying kinetics was described by the Henderson-Pabis and the third degree polynomial models in the case of HAD, FD and HAD-FD. The HAD carrot samples were exhibited shrinkage, case hardening, poor rehydration and brown surface. The FD carrot cubes appeared porous structure, excellent rehydration, soft texture and loose color. The HAD-FD samples were superior to HAD products and was nearer in quality to FD products with respect to appearance, rehydration and surface resistance (texture). Finally, it is concluded that HAD-FD is effective in improving the FD drying rate. However, the combined drying has a small-scale adverse effect on product quality.

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