scholarly journals A study of drying parameters on drying time and colour quality of grated coconut using tumbling mechanism in convective dryer

Food Research ◽  
2020 ◽  
Vol 4 (S6) ◽  
pp. 64-69
Author(s):  
S. Yahya ◽  
A. Mohd Shahrir ◽  
M.A. Amir Syariffudden ◽  
A. Shafie ◽  
J. Mohammad Shukri ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Small Scale ◽  
Drying Rate ◽  
Air Velocity ◽  
Drying Time ◽  
Hot Air ◽  
Significant Difference ◽  
Main Factors ◽  
Drying Behaviour

A small scale convective dryer with tumbling mechanism was specially constructed for drying grated coconut. This new drying mechanism was evaluated in term of drying behaviour and colour quality of the final product. Three main factors that involved were hot air temperature, rotational speed (rpm) and air velocity. Every combined parameter of a sample was compared to each other and also with freshly grated coconut. It was found that the combination of 60°C, 6 rpm and 4.31 ms-1 had the shortest drying time as well as the highest drying rate among other combinations. In contrast, combination factors of 50° C, 3 rpm and 2.06 ms-1 had the lowest drying rate. Three main factors; temperature, rotational speed and air velocity were significantly contributed to the response of drying time as (p<0.05). Drying rate also increased with increase in temperature, rotational speed and air velocity. In term of colour analysis (L*, a*, b*), there was a significant difference among dried grated coconut samples. Nevertheless, sample 60˚C, 3 rpm and 4.31 ms-1 and 50˚C, 3 rpm and 4.31 ms-1 showed no significant different (p>0.05) in lightness when compared to freshly grated coconut hence excellent in retaining its original appearance. On top of that, sample (60˚C, 3 rpm and 4.31 ms-1 ) also achieved considerable drying rate with an acceptable drying time of 135 mins.

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.

scholarly journals Small Scale Investigation of the Potential of Solar Drying of Water Hyacinth (Eichhornia Crassipes) as A Control Measure in Makurdi

2015 ◽  
Vol 6 ◽  
pp. 129-138
Author(s):  
A O Edeoja ◽  
A O Owolabi
Keyword(s):  
Water Hyacinth ◽  
Mixed Mode ◽  
Eichhornia Crassipes ◽  
Control Measure ◽  
Small Scale ◽  
Drying Rate ◽  
Aquatic Weed ◽  
Solar Drying ◽  
Water Weed

Water hyacinth is the world's worst water weed that is responsible for many environmental and economical problems. Nigerian fresh waters have been infested with this aquatic weed. In this work, a Natural Convection Mixed Mode Solar Dryer for drying water hyacinth to about 10% of its moisture content was constructed and tested as a component of controlling its infestation of the River Benue. The performance of the dryer was compared with the traditional open–air sun drying as the control for drying water hyacinth in Makurdi, Benue State Nigeria. The water hyacinth was dried for 8 hours each day for 4 days. 500g of water hyacinth on wet basis was dehydrated by about 437g on dry basis in 20 hours in the dryer while the control required 32 hours. The dryer was found to be technically more suitable for drying water hyacinth both in terms of the drying rate and quality of the dried product.

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

A numerical simulation of a line-type paint drying furnace

2019 ◽  
Vol 30 (5) ◽  
pp. 2639-2653
Author(s):  
Jongrak Choi ◽  
Giyeob Yang ◽  
Nahmkeon Hur
Keyword(s):  
Numerical Results ◽  
Drying Process ◽  
Drying Time ◽  
Content Type ◽  
Hot Air ◽  
Air Supply ◽  
Nozzle Configuration ◽  
Paint Drying ◽  
Line Type

Purpose Paint drying is a very important process in an industry where shorter drying time for productivity and lower energy consumption for production cost are required while maintaining the product’s painting quality. In the present study, a drying process in a line-type paint drying furnace equipped with nozzles for hot air supply and moving conveyer belt to dry painted automotive parts is numerically simulated for the flow and heat transfer inside the furnace to evaluate the quality of the drying or baking at the end of the drying process in a production line. Design/methodology/approach A baking window for a specific paint is used for judging the local degree of baking (DOB) of the painted parts, which can be useful to identify under-baked or over-baked locations of the painted parts, and hence the quality of the baking process. Findings Numerical results of a time history of temperatures at two monitoring points on the painted parts were obtained and compared to the measured data in an actual furnace and showed good agreement. Three types of paints were considered in the present study and numerical results showed different drying characteristics. In addition to the original furnace nozzle configuration, two more furnace nozzle configurations with different numbers, direction and speed of hot air supply were simulated to improve the furnace’s drying performance. As a result, a newly suggested nozzle configuration with quick drying paint can give us a remarkable improvement in surface averaged DOB compared to the original nozzle configuration with original paint. Originality/value The present simulation technique and DOB methodology can be used for the optimal design of a drying furnace.

scholarly journals Physiological and sensorial quality of Arabica coffee subjected to different temperatures and drying airflows

2017 ◽  
Vol 39 (2) ◽  
pp. 225 ◽  
Author(s):  
Guilherme Euripedes Alves ◽  
Flávio Meira Borém ◽  
Eder Pedroza Isquierdo ◽  
Valdiney Cambuy Siqueira ◽  
Marcelo Ângelo Cirillo ◽  
...  
Keyword(s):  
Germination Percentage ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Drying Time ◽  
Physiological Variables ◽  
Different Temperatures ◽  
Negative Effect ◽  
Physiological Quality ◽  
Sensorial Quality

The objective of this study was to evaluate the correlation between a group of physiological variables (electrical conductivity, potassium leaching, and germination percentage) and a group of drying kinetics variables (drying time and drying rate) in addition to verifying the relation between drying kinetics variables and coffee quality as a function of processing type, temperature, and drying airflow. Coffee drying was conducted in a fixed-layer dryer at two temperatures and two airflows. After drying, an evaluation of the physiological and sensorial quality was conducted. Based on the results obtained, the following conclusions were drawn: coffee that is processed via a dry method is more sensitive to mechanical drying with heated air than coffee processed via a wet method, resulting in poor physiological performance; airflow does not interfere with the physiological quality of pulped and natural coffees; a temperature increase from 40 to 45°C resulted in a decrease in the physiological quality only for pulped coffee; and an increase in the drying rate as a result of an increase in the drying temperature to 40°C had a negative effect on the sensorial quality of pulped coffee. 

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.

A Prospective, Randomized Trial Comparing a Transparent Dressing and a Dry Gauze on the Exit Site of Long Term Central Venous Catheters of Hemodialysis Patients

2003 ◽  
Vol 4 (2) ◽  
pp. 56-61 ◽  
Author(s):  
I. Le Corre ◽  
M. Delorme ◽  
S. Cournoyer
Keyword(s):  
Quality Of Life ◽  
Hemodialysis Patients ◽  
Exit Site ◽  
Skin Preparation ◽  
Drying Time ◽  
Skin Reactions ◽  
Significant Difference ◽  
The Cost

The objective of this study was to assess the risk of bacteremia, estimate the cost and evaluate the quality of life by using a transparent dressing (TD) versus (vs) a dry gauze (DG) on the exit site of long term central I.V. catheters (LTCC) of hemodialysis patients. This 6-months preliminary study was conducted on 58 patients (pts) randomized to receive DG replaced 3 times/week (29 pts) or TD replaced every 7 days (29 pts). Data on patients, conditions of the exit site, local infection, bacteremia, quality of life and cost related to each type of dressing were collected. Two pts in the DG group experienced bacteremia related to their LTCC vs 1 pt in the group TD. A total of 7 (DG) vs 13 (TD) pts experienced skin condition changes at the catheter exit site. Some skin reactions, erythema and pruritus, did occur initially in the group TD and was due in part to insufficient drying time of the skin preparation solution. The estimated individual, weekly costs for using the DG was $7.60 vs $4.72 Canadian dollars for the TD. The SF-36™ scores did not show a significant difference between the 2 groups during the study (3.8 (PCS), 6.4 (MCS) at study end). Although this study was statistically underpowered, it suggests that the incidence of bacteremia was not increased with the use of a TD. Moreover, the use of a TD allowed fewer dressing changes, lowered total treatment costs, with no observed unfavorable impact on the quality of life and without significant local complications of the exit site. Based on the positive results observed in this pilot study, further study is warranted to examine the cost effectiveness of long-term use of TD dressings on dialysis catheter exit sites.

Effect of Air Velocity and Temperature on the Drying Kinetics of Drumstick Leaves (Moringa Oleifera)

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
Monica Premi ◽  
Harish Sharma ◽  
Ashutosh Upadhyay
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Moringa Oleifera ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Air Velocity ◽  
Drying Time ◽  
Effective Moisture ◽  
Kinetics Of

Abstract The present study examines the effect of air velocity on drying kinetics of the drumstick leaves in a forced convective dryer. The drumstick leaves were dried in the temperature range of 50–800 C, at different air velocity (Dv) of 0.5 and 1.3 m/s. The results indicated that drying temperature and air velocity are the factors in controlling the drying rate. Experimental data obtained for the samples for color, drying rate and drying time proved that air velocity of 1.3 m/s yielded the product superior in terms of both quality and energy efficiency as compared to the samples at 0.5 m/s. Activation energy for drumstick leaves dried with air velocity, 0.5 and 1.3 m/s was 12.50 and 32.74 kJ/mol respectively. The activation energy relates similarly with the effective moisture diffusivity which also increased with increase in air velocity and temperature.

scholarly journals The Effect of Preservation Methods on the Nutritional Quality of Fluted Pumpkin (Tel/airia occidentalis) Leaves

2011 ◽  
Vol 54 (3) ◽  
pp. 167-171
Author(s):  
Fred Omon Joseph Oboh ◽  
Osayuwamen Aigbe
Keyword(s):  
Citric Acid ◽  
Vitamin C ◽  
Boiling Water ◽  
Drying Time ◽  
Iron Protein ◽  
Oven Drying ◽  
Fluted Pumpkin ◽  
Significant Difference ◽  
Pre Treatment

The present research was undertaken to investigate the effect of various blanching and drying treatments on the vitamin C, �-carotene, iron, protein content and drying time of fluted pumpkin (Telfairia occidentalis Hook) leaves. The leaves were subjected to sun or oven drying alone or after blanching in boiling water, dilute citric acid (0.3%) or dilute potassium meta-bisulphite (0.5%). In the absence of blanching pre-treatment, oven drying resulted in shorter drying time for the leaves and a higher vitamin C content of the dried product than sun drying and there was no significant difference (p>0.01) between the protein, �-carotene and iron content of the oven and sun dried products. Leaves blanched in boiling water, dilute citric acid, or dilute potassium meta-bisulphite solution, followed by sun or oven drying had less vitamin C, iron, protein and �-carotene than leaves dried without blanching. Compared with the use of boiling water, blanching in boiling potassium meta-bisulphite reduced the loss of �-carotene, protein and iron; blanching in dilute citric acid reduced the loss of iron. Except for citric acid pre-treatment, blanching prior to drying shortened drying time.  

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