Drying of Rough Rice Using Heated Husk for Heat Transfer and Moisture Adsorption

2018 ◽  
Vol 34 (3) ◽  
pp. 605-615 ◽  
Author(s):  
Sammy S. Sadaka ◽  
Griffiths G. Atungulu
Keyword(s):  
Heat Transfer ◽  
Moisture Content ◽  
Rice Husk ◽  
Rice Yield ◽  
Ambient Air ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Air Drying ◽  
Rough Rice ◽  
Rice Samples

Abstract. Drying of small size samples usually represents a challenge to rice researchers. Using natural air drying to dry these samples exposes them to the fluctuations of ambient air conditions. Therefore, the goal of this research was to evaluate the suitability of drying small size rough rice samples using heated husk as a heat transfer and moisture adsorbent medium. The proposed drying technique could be an attainable process, particularly because it represents conduction heat and moisture transfer rather than natural air drying. The required amounts of rice husk were placed in aluminum containers and kept in an oven overnight to reach the desired temperature. Heated husk samples were mixed with rough rice and maintained for the desired drying duration; following which, the husk and rough rice mixtures were separated pneumatically. The separated rough rice samples were collected to determine moisture content, drying rate, and rice quality. The highest mixture temperature of 34.0°C was achieved at the highest husk to rough rice ratio of 1:2 and the highest husk temperature of 110°C after 4 minutes. A maximum of 6.4% moisture reduction points was achieved by mixing the rice husk to rough rice by 1:2 on a weight basis and employing heated rice husk at 100°C. The highest drying rate of 5.99%/h was achieved during the first hour of drying with the husk-to-rough rice ratio of 1:2 and the husk temperature of 100°C. Milled rice yield ranged between 63.4% and 72.0% while the head rice yield ranged between 39.9% and 67.9%. An empirical correlation was developed to calculate the normalized moisture content as a function of the husk to rough rice ratio, the husk temperature and drying duration with a coefficient of determination of 0.775 under the studied conditions. Keywords: Conduction drying, Heat transfer medium, Moisture absorbent, Rice husk, Rough rice.

Finite Element Simulation of Drying of Rough Rice

2011 ◽  
Vol 312-315 ◽  
pp. 860-864 ◽  
Author(s):  
Oktay Hacıhafızoğlu ◽  
Ahmet Cihan ◽  
Kamil Kahveci
Keyword(s):  
Finite Element ◽  
Moisture Content ◽  
Single Layer ◽  
Ambient Air ◽  
Simulation Software ◽  
Drying Rate ◽  
Element Simulation ◽  
Rough Rice ◽  
Drying Behavior ◽  
Positive Effect

Rough rice has high moisture content at harvest, and if their moisture content is not reduced to about 12% on the dry basis they decay due to infestation and mold growth. Drying process is generally performed by heating ambient air and then sending it by forced convection over the rough rice to be dried. The aim in heating air to a certain temperature is to reduce the relative humidity of the air, which has a positive effect on the drying potential. In this study, drying behavior of single layer rough rice for different drying air temperature was simulated by means of a liquid diffusion model numerically by finite element modeling and simulation software. The results show that temperature is an effective factor on the drying rate. The results also show that as drying proceeds, a moisture gradient develops within the grain. This slows down the drying rate considerably. Therefore, it can be concluded that performing drying with an intermittent period instead of continuous drying will cause a considerable energy-saving.

Drying of Rough Rice in Oven: An Experimental Study

2015 ◽  
Vol 365 ◽  
pp. 77-81 ◽  
Author(s):  
J.V. Silva ◽  
E.M.A. Pereira ◽  
T.H.F. Andrade ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Experimental Study ◽  
Relative Humidity ◽  
Moisture Content ◽  
Product Quality ◽  
Air Temperature ◽  
Drying Rate ◽  
Rough Rice ◽  
Drying Conditions ◽  
Kinetics Of ◽  
Mechanical Movement

This paper aims to present an experimental study of rough rice (BRSMG CONAI cultivar) drying by using a stationary method. The grain was dried in an oven with air mechanical movement under controlled conditions of velocity, temperature and relative humidity. In order to obtain balanced moisture content, the samples studied were kept at 40 and 70°C. Results of the drying and heating kinetics of the grain during the process are shown and analyzed. It was found that higher drying rate and lower time for drying as higher air temperature (70°C) is used. It can be concluded that the reduction of the moisture content of the grain, is considered very complex and, depending on the method and drying conditions, can substantially provokes breaking and cracks, which reduces final product quality.

Effect of Storage Moisture Content on Milling Characteristics of Rough Rice

2019 ◽  
Vol 62 (4) ◽  
pp. 1011-1019
Author(s):  
Bhagwati Prakash ◽  
Terry J. Siebenmorgen ◽  
Kristen E. Gibson ◽  
Shweta Kumari
Keyword(s):  
Moisture Content ◽  
Rice Yield ◽  
Surface Lipid ◽  
Milled Rice ◽  
Financial Return ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield ◽  
Milling Characteristics ◽  
The Mean

Abstract. Rough rice in the Mid-South U.S. is typically stored and milled at a moisture content (MC) between 12% and 13% on a wet basis. Drying harvested rice to lesser MCs requires increasingly greater energy and reduces the overall mass of rice, both of which translate into lesser financial return for the crop. Considering these disadvantages of drying and storing rice at lesser MCs, farmers and grain handlers have been interested in exploring storing rice at slightly greater MCs. The current study was undertaken to evaluate the effect of storing rice at five MCs (11%, 12%, 13%, 14%, and 15%) on milling characteristics, particularly surface lipid content (SLC), milled rice yield (MRY), and head rice yield (HRY); additionally, the effects of storing rice at two storage temperatures (25°C and 35°C) and several storage durations (up to one year) on milling characteristics were investigated. Five long-grain rice lots were harvested in 2016 and 2017 from several locations in Arkansas; rice from each lot was gently dried to the target MCs and then stored in sealed glass jars at selected temperatures. With an increase in storage MC, shorter milling durations were needed to achieve a given SLC, which could potentially reduce the cost of the milling operation. However, rice samples stored at greater MCs were observed to have lesser HRYs, which could reduce the economic value of rice. The mean HRYs of the 15% MC samples were 4.8 to 9.1 percentage points less than the mean HRYs of the 12% MC samples. This study quantifies the milling characteristics of rice when stored for various durations at different MCs and temperatures. Overall, these data will allow the rice industry to make informed decisions related to storage conditions of rice, specifically storage MC. Keywords: Head rice yield, Milling, Moisture content, Rice, Storage.

Effect of Drying on Physical Qualities and Sensory Evaluation of Herbal Germinated Brown Rice by Hot Air: Turmeric and Roselle

2013 ◽  
Vol 372 ◽  
pp. 420-423
Author(s):  
Khwanruedi Sangchum ◽  
Yutthana Tirawanichakul ◽  
Supawan Tirawanichakul
Keyword(s):  
Moisture Content ◽  
Sensory Evaluation ◽  
Initial Moisture Content ◽  
Brown Rice ◽  
Ambient Air ◽  
Drying Rate ◽  
Germinated Brown Rice ◽  
Rice Drying ◽  
Drying Conditions ◽  
Cie Lab

The object of this project was to study the effect of drying temperature on physical quality and sensory evaluation of germinated brown rice soaking with tumeric and roselle. The drying was run under the conditions of drying temperatures of 80-100°C and air velocity of 7.3 m/s. Initial moisture content of brown rice samples was of 54-55% dry-basis and was dried until the final moisture content reached to 20-25% dry-basis. After drying, the rice was tempered and then was ventilated by ambient air until its moisture content reached to 14-15% dry-basis. The experiment showed that highest drying rate is incident at 100°C. For physical qualities analysis, the results showed that the drying air temperature does not affect to head rice yield, fissured kernels, chalky grain and color (L*, a*, b* CIE-lab unit) of herbal germinated brown rice. In addition, herbal germinated brown rice drying can maintain low percentage of chalky grain compared to commercial brown rice. The soaking solution was not affect to drying rate. Finally, the sensory evaluation showed that the herbal germinated brown rice dried with all drying conditions was acceptable taste (>5).

scholarly journals Hot air drying combined vacuum-filling nitrogen drying of apple slices: Drying characteristics and nutrients

2018 ◽  
Author(s):  
Xiaoli Huang ◽  
T. Li ◽  
S.N. Li ◽  
Z.H. Wu ◽  
J. Xue
Keyword(s):  
Moisture Content ◽  
Drying Rate ◽  
Slice Thickness ◽  
Relative Pressure ◽  
Hot Air Drying ◽  
Air Drying ◽  
Drying Characteristics ◽  
Hot Air ◽  
Apple Slices ◽  
Apple Slice

In this paper, hot air drying (HAD) was applied when moisture content of apple slices range from 50% to 86%, and then vacuum-filling nitrogen drying (VFND) was used till moisture content reaching 7%. Results showed that, the drying rate of apple slice during VFND period increased with temperature increment and decreased with increment of slice thickness; compared to freezing dried samples,  samples dried in this research were owned lower Vc and higher flavonoid; when HAD (70℃,3.0m/s)+VFND(relative pressure 0.08MPa, 50℃) and thickness of 6.0mm, nutrients reached better levels: retentions of Vc, total phenolics and flavonoid were 1.63mg/100g, 4.07mg/100g and 2.10mg/100g, respectively. Keywords: apple slices, hot air drying, vacuum-filling nitrogen drying, drying rate, nutrients

scholarly journals Convective Thin-Layer Drying Characteristics of Sesame Seed

2012 ◽  
Vol 7 ◽  
pp. 55-62 ◽  
Author(s):  
O.U. Dairo ◽  
T.M.A. Olayanju
Keyword(s):  
Moisture Content ◽  
Thin Layer ◽  
Initial Moisture Content ◽  
Sesame Seed ◽  
Effective Diffusivity ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Fundamental Information ◽  
Thin Layer Drying ◽  
Page Equation

Fundamental Information on Drying and Re-Wetting Characteristics of Agricultural Seeds Is Required in the Design and Aeration Systems as Well as in the Prediction of Drying Rate Using Various Mathematical Models. Thin-Layer Drying Experiments Were Conducted Using Air-Ventilated Oven to Simulate the Artificial Drying at Various Moisture Contents of Sesame Seed (6.9 to 18.2 % W.b) at Three Drying Temperatures of 40, 50 and 60OC. Five Drying Models Were Evaluated for the Thin-Layer Data. the Page Equation Fitted the Data Best, where Selection of the Best Model Was Obtained by Comparing the Coefficient of Determination (R2), the Standard Error of Moisture Content (SEM) and Mean Relative Percent Error (e) between the Experimental and Estimated Values. the Drying Rate of Sesame Seed under Drying Conditions Increased with Increased Temperature of Drying( 40 to 60OC) and Initial Moisture Content of Seed( 6.9, 11.5 and 18.2 % W.b). the Parameters “K” of the Page Model Increased with Increase in Temperature, while, Parameter ”n” Decreased with Temperature Increase and Increased with Increase in Moisture Content of Seed. the Effective Diffusivity Was Found to Be 2.32 X 10-11 M2s-1.

Impacts of Specific Power of Microwave at 915 MHz Frequency on Drying and Milling Characteristics of Parboiled Rough Rice

2021 ◽  
Vol 37 (2) ◽  
pp. 359-366
Author(s):  
Deandrae Lynette Smith ◽  
Griffiths G. Atungulu
Keyword(s):  
Rice Yield ◽  
Least Square ◽  
Specific Power ◽  
Drying Rate ◽  
Milled Rice ◽  
Volumetric Heating ◽  
Parboiled Rice ◽  
Rough Rice ◽  
Milling Characteristics ◽  
Drying Rates

HighlightsThis research investigated the feasibility of using a microwave (MW) set at 915 MHz frequency to dry high moisture content (MC) parboiled rough rice at 44.3% MC dry basis (d.b.).The research evaluated the impacts of specific power delivered during the drying of parboiled rough rice using a MW on post-drying milling characteristics.The volumetric heating phenomenon provided by MW offered a method to quickly remove 23.1% points of moisture from parboiled rough rice in one-pass to a MC of 21.2% d.b., with minimal impacts on the kernel quality.The findings suggest that increased MW specific powers have a positive effect on rice MC reduction but negatively affects the rice milling characteristics, especially the head rice yield.The study recommended that MW specific powers exceeding 2.92 kW.[kg-DM]-1 should not be exceeded during drying of parboiled rough rice to preserve the rice milling yields.ABSTRACT. The objectives of this research were to study the impacts of specific power of MW generated at 915 MHz frequency to dry high MC parboiled rough rice on moisture removal and milling characteristics of the parboiled rough rice. Long-grain rough rice of the cultivar (cv.) Mermentau at harvest MC of 31.6% dry basis (d.b.) was parboiled by soaking at 73°C for 3 h and then steamed at 67 kPa for 10 minutes. Following the parboiling process the sample was subjected to the MW drying. The drying was accomplished at MW specific powers that ranged from 1.10 to 8.77 kW. [kg-DM] -1 and 0.37 to 2.92 kW. [kg-DM] -1 (power per unit dry matter mass of the grain). These treatment levels of MW specific power were varied by heating parboiled rough rice for 2 and 6 minutes (min) at MW powers that ranged from 1 to 24 kW. The process of parboiling increased the rough rice MC to 44.3% dry basis (d.b.). During the MW drying, as the specific power increased, the general tendency was for rough rice final moisture content (FMC), milled rice yield (MRY) and head rice yield (HRY) to decrease while the drying rate increased. Parboiled rough rice samples treated with a specific power of 8.77 kW.[kg-DM] -1 while maintaining specific energy input at 0.29 kWh.[kg-DM] -1 had least-square means FMC, drying rate, MRY and HRY of 19.7% d.b. (S.D ± 1.1%), 12.3% d.b. [min-1] (S.D ± 0.8%) (2 min drying duration), 68.18% (S.D ± 1.70%) and 67.51% (S.D ± 0.73%) respectively. However, treatment at a lower specific power of 2.92 kW.[kg-DM] -1 while maintaining the same specific energy input of 0.29 kWh.[kg-DM]-1) resulted in least-square means FMC, drying rate, MRY and HRY of 21.2% d.b. (S.D ± 0.5%), 3.9% d.b. [min-1] (S.D ± 0.1%) (2 min drying duration), 73.22% (S.D ± 0.84%) and 73.21% (S.D ± 0.21%) respectively. The increased drying rates for treatments with higher specific power was associated with higher treatment powers and shorter treatment durations. Higher specific powers negatively impacted the observed MRY and HRY. The findings suggest that increased MW specific powers have a positive effect on rice MC reduction but above a certain threshold of specific power (2.92 kW.[kg-DM]-1) may negatively affect the milling characteristics of the parboiled rice. When used to dry high MC parboiled rough rice, rice processors should know that there exists an optimum drying rate that if exceeded the milled rice quality is negatively affected thus generating an economic loss to the parboiled rice industry. The volumetric heating phenomenon provided by microwave (MW) offers a means to quickly dry high MC parboiled rough rice. This can translate to considerable economic savings for the rice processor who often experiences low drying rates because of limited drying capacity, especially at peak rice harvest times. When drying rates are optimized, rice processors can expect minimal impacts on the kernel quality which can also be translated to considerable economic savings for the rice processor. Keywords: 915 MHz microwave, Microwave drying, Milling Quality, Parboiled rice, Specific power.

Development of Prediction Model for Harvest Moisture Content of Rough Rice Using Meteorological Data and Color Characteristics

2021 ◽  
Vol 37 (6) ◽  
pp. 1063-1071
Author(s):  
Hoon Kim ◽  
Oui Woung Kim ◽  
Jae Woong Han ◽  
Hyo-Jai Lee
Keyword(s):  
Moisture Content ◽  
Prediction Model ◽  
Meteorological Data ◽  
Coefficient Of Determination ◽  
Harvest Time ◽  
Leaf Color ◽  
Rough Rice ◽  
Accumulated Temperature ◽  
Harvest Moisture

HighlightsMoisture content, meteorological data, and leaf color characteristics of rice were investigated by harvest time.The moisture content decreased, and leaf color value increased as days after heading passed.Harvest moisture content prediction models were developed using meteorological data and leaf color.It is necessary to use both leaf color and meteorological data to determine the harvest time.Abstract.In this study, ambient temperature, accumulated temperature, and rice leaf color values were measured before harvest time to develop models for predicting the harvest moisture content (HMC) of short-grain rice. Field tests were conducted on Chuchung and Whang-gum-nu-ri, which are short-grain rice cultivars, at different experimental plots, for four years. As days after heading (DAH) passed, the moisture content (MC) decreased, and leaf color (L*, a*, and b* values) tended to increase. An experimental model that can predict HMC was developed based on the experimental results of 3 years, and the experimental results of the remaining 1 year were used for verification. The coefficient of determination of the HMC prediction model that used ambient and accumulated temperatures was 0.719, and that of the prediction model that used leaf color was as low as 0.418. However, the coefficient of determination of the integrated model that used all the factors, i.e. ambient and accumulated temperatures and leaf color, was as high as 0.915. Therefore, to determine the harvest time using the HMC of rough rice, leaf color, and meteorological data should be used together. Leaf color tended to increase markedly as the DAH increased, but the leaf color values were not similar for the same MC each year. This is because leaf color is influenced not only by MC but also by various cultivation factors such as soil conditions and growth rate during the rice cultivation process. Keywords: Accumulated temperature, Harvest, Harvest moisture content, Leaf color, Rice, Short variety.

Effect of Rice Cultivar, Type, Form, and Moisture Content on the Angle of Repose

2019 ◽  
Vol 35 (4) ◽  
pp. 361-368
Author(s):  
Hu Shi ◽  
Terry J. Siebenmorgen
Keyword(s):  
Moisture Content ◽  
Hybrid Rice ◽  
Brown Rice ◽  
Rice Cultivar ◽  
The United States ◽  
Angle Of Repose ◽  
Rice Cultivars ◽  
Milled Rice ◽  
Rough Rice ◽  
Rice Samples

Abstract.The angle of repose (AoR) is a primary characteristic determining the flowablity of grains and thus is an important property for designing rice handling and storage facilities. The aim of this study was to evaluate the AoR of contemporary rice cultivars grown in the United States. An apparatus was constructed to measure both the emptying and piling AoR of rice samples. The effect of rice cultivars (pureline and hybrid), rice types (long-, medium-, and short-grain rice), rice forms (rough, brown, head, and broken milled rice), and moisture content on the AoR of rice were evaluated. Results indicated that all of these factors significantly affected the AoR of rice. The piling AoR was significantly less than the emptying AoR. Hybrid rice cultivars tended to have greater AoR than purelines, which was attributed to the pubescence characteristic of their hulls. The emptying AoR and piling AoR of tested long-grain rough rice cultivars at 12% to 21% moisture content were in the range of 32.7° to 39.7° and 29.6° to 36.9°, respectively.Increasing the moisture content of long-grain rough rice led to greater AoR, possibly due to increased cohesion of rice kernels. Long-grain rough rice cultivars had slightly lesser AoR than those of medium- and short-grain rice cultivars. Among all tested rice forms, brown rice had the least AoR. Head and broken milled rice had approximately the same AoR as rough rice. Keywords: Angle of repose, Bridging, Flowablity, Friction, Rice.

Head rice yield response to low and high drying and tempering conditions

2013 ◽  
Vol 27 (2) ◽  
pp. 219-223 ◽  
Author(s):  
M. Sadeghi ◽  
E. Nasrnia ◽  
A.A. Masoumi ◽  
A. Hemmat
Keyword(s):  
Moisture Content ◽  
Rice Yield ◽  
Yield Response ◽  
Rice Varieties ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield ◽  
Yield Values ◽  
High Head ◽  
Drying Conditions

Abstract The influence of drying and tempering conditions on head rice yield of long- and medium-grain rough rice varieties was investigated. The head rice yield values for the medium-grain variety at high drying conditions and 1.5 and 3% points moisture content removal were even significantly higher than the corresponding values for the long-grain variety at low drying conditions. 1.5% points moisture content removal yielded the least damage to the rough rice. Under low drying conditions, tempering had no meaningful effect on head rice yield for all drying durations. For both varieties, using high drying conditions with 6% points moisture content removal at first drying stage associated with 120 min tempering duration could be suggested as a rapid and energysaving operation to achieve high head rice yield values.

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