scholarly journals EFFECT OF TWO STAGE DRYING EMPLOYING FLUIDIZED BED DRYING, TEMPERING FOLLOWED BY FIXED BED DRYING ON HEAD RICE YIELD OF BRRI DHAN28 RICE VARIETY IN BANGLADESH

2021 ◽  
Vol 2 (2) ◽  
pp. 74-78
Author(s):  
Md. Abdul Wazed ◽  
N. H. M. Rubel Mozumder ◽  
Md. Sazzat Hossain Sarker

Drying of high moisture paddy to achieve quality milled rice is an important issue in a paddy producing country like Bangladesh. This study has been conducted to investigate the impact of two stage drying technique namely, fluidized bed drying, tempering and followed by fixed bed drying method on quality of BRRI Dhan28 rice variety in terms of head rice yield (HRY). Moist paddy was dried in fluidized bed dryer (FBD) as first stage drying to reduce moisture from 25-27% to 18-19% using three drying temperatures of 120, 130, and 150°C at three bed thicknesses of 8, 10, and 12 cm. The first stage dried samples were immediately tempered for 30 minutes and dried in second stage drying by fixed bed dryer using 40±10C temperature maintaining bed thickness as 30 cm for the further reduction of moisture content to 13-14% (wb). Sun drying method was followed as complete drying of control sample. Control sample was used to compare the milling quality of rice dried in two stage drying technique. In addition, head rice yield was also compared to existing industrial paddy drying complexes. The results revealed that HRY of rice samples obtained from different drying methods was comparable. All the sets of drying parameters in two stage drying yielded better quality HRY than the control and even existing industrial drying method. The highest HRY (53.43%) of milled rice was obtained in the two-stage drying. On the other hand, the samples dried in the sun drying and industrial drying using Louisiana State University (LSU) dryer yielded 49.77% and 48.25% HRY, respectively. Therefore, the two-stage drying technique can be used for drying of high moisture paddy to obtain quality dried rice.

2021 ◽  
Vol 39 (4) ◽  
pp. 1247-1254
Author(s):  
A.B. Muochebe ◽  
O.C. Nwajinka ◽  
I.E. Nwatu

Optimization study was carried out on the parboiling process variables for improving the milling quality of FARO-44 rice variety using Response Surface Methodology (RSM) in Central Composite Design (CCD). The variables studied were initial soaking temperature (IST), soaking time (SKt) and steaming time (STt) including their interactive effects.The range of the input variables studied were 70-90oC, 8-12hrs and 40-50minsfor initial soaking temperature, soaking time and steaming time respectively. For thisstudy, a total of twenty (20) randomized experimental runs comprising one (1) replicate of factorial point, one (1) replicate of axial point (alpha 2.7) and six (6) centre point in the design space. Analyses of variance (ANOVA) were performed on the experimental data sets and models were fitted for all the response variables generated. The result showed that the optimal parboiling variables were, 90 0C, 46mins and 10 hours,for initial soaking temperature, steaming time and soaking time respectively with their corresponding optimum response 58.7%, 6.7% and 58.1% for Head rice yield (based on parboiled paddy weight), breakage ratio and milled rice colour (based on illumination). The  composite desirability is 0.793 which maximized the percentage Head rice yield (HRY) and milled rice colour (MRC) but minimized the percentage Breakage Ratio (BR). Keywords: optimization, Response Surface Methodology, FARO-44, Rice,Head rice, parboiling 


2020 ◽  
Vol 187 ◽  
pp. 01002
Author(s):  
Asadayuth Mitsiri ◽  
Somkiat Prachayawarakorn ◽  
Sakamon Devahastin ◽  
Wathanyoo Rordprapat ◽  
Somchart Soponronnarit

A more simple methodology of producing parboiled rice is subject to be investigated in this work with proposed the method, the gelatinization of rice starch, commonly taking place at the steaming step in the traditional process, and drying are combined and replaced by a hot air fluidized bed dryer. A pilot-scale continuous fluidized bed, with a maximum capacity of 140-150 kg/h, has been designed, constructed and tested. Suphanburi 90 paddy variety with high amylose content was dipped into hot water at temperatures of 70, 80, 83°C for 4.0, 3.3, 3.2 h, respectively, to get the moisture content around 47-55% db and dried at 150-170°C using air speed of 3.5 m/s. The paddy bed depth within the dryer was 3 and 5 cm. In the dryer operation, the exhaust air was fully recycled and reheated again by 30 kW electrical heaters to the desired temperature. The experimental result has shown that parboiled rice with a different degree of starch gelatinization could be produced by this technique. The degree ranged between 80-100% as examined by differential scanning calorimeter. The exit moisture content was given in a range of 14-21% db, relying on the drying temperature and soaking time. The aforementioned exit moisture contents were not a detrimental effect on head rice yield although the tempering was not included. The head rice yield was given in the range of 59-66%, depending on the degree of starch gelatinization. The starch granules lost their original shape as revealed by scanning electron microscope.


2017 ◽  
Vol 33 (5) ◽  
pp. 721-728 ◽  
Author(s):  
Zephania R. Odek ◽  
Bhagwati Prakash ◽  
Terry J. Siebenmorgen

Abstract. X-ray imaging is a viable method of fissure detection in rough rice kernels owing to the ability of X-rays to penetrate hulls, thus allowing visualization of internal rice kernel structure. Traditional methods of fissure detection are only applicable for brown and milled rice, and therefore cannot be used to study fissures developed during rough rice drying. In this study, the fissure detection capability of an X-ray system was evaluated and the relationship between head rice yield (HRY), as measured through laboratory milling, and the percentage of fissured rough rice kernels was determined. Long-grain rice lots of various cultivars were dried using heated air at 60°C, 10% relative humidity (RH) for five drying durations to produce different degrees of fissuring, and then milled to determine HRY. A strong linear correlation (R2 = 0.95) between HRY and the percentage of fissured rough rice kernels after drying was determined. This correlation confirms the substantial impact that kernel fissures have on milling yields. Overall, these findings show the effectiveness of X-ray imaging in rough rice fissure detection, which could allow for drying research that may provide a better understanding of kernel fissuring kinetics. Keywords: Fissures, Grainscope, Head rice yield, Rice drying, X-ray imaging.


2019 ◽  
Vol 62 (4) ◽  
pp. 1011-1019
Author(s):  
Bhagwati Prakash ◽  
Terry J. Siebenmorgen ◽  
Kristen E. Gibson ◽  
Shweta Kumari

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.


2020 ◽  
Vol 36 (4) ◽  
pp. 579-588
Author(s):  
Zeinab Mohammadi Shad ◽  
Griffiths Atungulu

Highlights Rice kernel physical integrity diminished at higher storage temperature and moisture content. Variation in rice kernel physical integrity was noticeable among rice cultivars. Fungal attack lessened rice kernel physical integrity. Abstract . Rice kernel physical integrity directly correlates with rice milling yield and quality. In this study, the impact of storage conditions on rice kernel physical integrity was examined by assessing changes in head rice yield (HRY) and kernel microstructure. Long-grain hybrid (XL753), long-grain pureline (Roy J), and medium-grain (Titan) rice were stored at different storage moisture contents (16% and 21% MCs, wet basis), storage temperatures (20°C, 30°C, and 40°C), and storage durations (4, 8, 12, and 16 weeks); the samples were also treated with antifungals, sodium chloride, and natamycin. Results show that kernel physical integrity was highly dependent on the rice storage environment. At the same storage conditions, the physical integrity of medium-grain cultivar was significantly higher than that for the two long-grains. Generally, the long-grain hybrid rice exhibited more resilience to breakage than pureline under the same storage conditions. An average of 4% reduction in HRY was seen for the three cultivars when 16% MC rice was stored at 40°C compared to at 20°C; however, the HRY reduction was 12% for rice stored at the highest MC (21%). Decreases in kernel physical integrity were also associated with unique microstructural changes in rice kernels. Sodium chloride treatment of rice kernels significantly and negatively impacted their physical integrity during storage compared to natamycin treatment and untreated control samples. Multiple regression models, developed for each cultivar were applicable for predicting changes in rice kernel physical integrity as a function of studied storage conditions and antifungal treatments. Keywords: Antifungal treatment, Head rice yield, Microstructure, Milled rice quality, Storage, Rice kernel physical integrity.


Author(s):  
Reza Farahmandfar ◽  
Esfandiyar Farahmandfar ◽  
Mahdi Ghasemi Varnamkhasti ◽  
Mahdi Zarei

Milling, an important processing step of rough rice, is usually done to produce white, polished grains. In this paper the quality of 22 milled rice varieties, common in Mazandaran, Iran, are investigated. These rice varieties included local varieties and breeding lines. Parameters assessed were head rice yield, degree of milling, husk removed percent, and total milling recovery. Results obtained revealed that the Tarom Mahali and Champa varieties have the highest head rice yield as 60.58 and 66.39 % and total milling recovery as 69.96 and 71.38 %, respectively. The greatest degree of milling value was found for the Haraz variety with a mean of 16.06 %. Also, it was found that the husk removed percent values were not statistically different among the varieties studied. Finally, considering all results obtained, the varieties of Tarom Mahali, Champa, and Neda showed to be more economical in the milling process.


2018 ◽  
Vol 34 (5) ◽  
pp. 877-885 ◽  
Author(s):  
Kaushik Luthra ◽  
Sammy Sadaka ◽  
Griffiths G Atungulu

Abstract.Several researchers have reported that drying freshly harvested rough rice to safe storage moisture content of 14.9% d.b. in fluidized bed dryers resulted in a decrease in head rice yield, as compared with traditional drying methods. This phenomenon was attributed to the high thermal stress that affects rice kernels. The present study hypothesized that drying rough rice in fluidized bed dryers subjected to retention duration would maintain the rice quality as it may reduce the thermal stress. Therefore, the goal of this research was to investigate the effects of heating and retention durations on the dried rice head yield and energy consumption in a fluidized bed dryer. A bench-scale fluidized bed dryer was developed and tested. The effects of drying duration of 10, 20, and 30 min and the retention duration of 0, 15, 30, 45, and 60 min on rough rice moisture content, drying rate, head rice yield, and energy consumption were investigated. During the retention period, paddy released a considerable amount of moisture. This moisture reduction, achieved during retention period, was obtained without any additional heating cost and was a supplement to the overall drying process. The retention period helped with thermal stress management within rice kernels and resulted in maintaining the head rice yield as compared to the rice dried without retention duration. Considering all the studied heating and retention durations, the head rice yield values of rice samples varied from 46.0% to 51.0%. The lowest energy consumption of 3.31MJ/kg waterremoved was achieved at the heating duration of 10 min and the zero retention duration. This value represents 1.44 folds of the theoretical energy required to remove 1 kg of moisture from organic matter. Keywords: Drying, Energy consumption, Head rice yield, Moisture content, Retention duration, Rough rice.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Ayenew Meresa ◽  
Ayalew Demissew ◽  
Seifu Yilma ◽  
Getu Tegegne ◽  
Kiber Temesgen

Most locally cultivated rice varieties in Ethiopia have low physical (low head rice yield, high broken rice yield, and high percentage of chalkiness) and cooking qualities (low water uptake ratio and swelling ratio). Parboiling, a process which involves soaking, steaming, and drying, has been identified as a key technique to improve cooking and milling quality of rice. The current study is aimed at elucidating the effect of parboiling on physical and cooking qualities of three rice varieties (Gumara, Edget, and Narica4) collected from Fogera National Rice Research and Training Center, Amhara region, Ethiopia. Each rice variety was subjected to different soaking temperatures (40°C, 50°C, 60°C, 70°C, and 80°C) and steaming time (10, 20, 30, 40, and 50 minutes). The treatment effect results indicated that parboiling has a significant effect (P<0.05) on head rice yield and percentage of broken rice with increased soaking temperature and steaming time as compared to the control. For instance, percent head rice yield increased as soaking temperature (from 40 to 80°C) and steaming time (from 10 to 50 min) increased: for Gumara, from 4.07 to 93.6%, for Edget, 9.47 to 96.53, and from 3.20 to 91.67 for Narica4. Percentage chalkiness had decreased as soaking temperature and steaming time increased: 97.33% to 0.00% for Gumara, 97.80% to 0.00% for Edget, and 100.00% to 0.13% for Narica4 as compared to 100% for control of all varieties. The minimum cooking time was identified as 16-23 min for Gumara, 16-23 min for Edget, and 15-20 min for Narica4 rice varieties. The result of the present study clearly showed that parboiling with high soaking temperature and steaming time increased the head rice yield, water uptake ratio, decreased percentage chalkiness, and enhanced the overall quality of the rice varieties.


2012 ◽  
Vol 472-475 ◽  
pp. 1707-1713
Author(s):  
Pradit Ramatchima ◽  
Somposh Sudajan ◽  
Chaiyan Junsiri ◽  
Thavachai Thivavarnvongs

This research was aimed at studying the effects of heating the paddy for insect killing and thereby improving subsequently milled rice quality. The experimental temperatures were in the range of 120-200°C, the paddy feeding rates were 60, 120, and 180 kg/h and the heights of the vibration screen were 5, 6, and 8 mm. The findings indicated that when the feeding rates increased between 120 and 180 kg/h, the insect death rate increased for nearly all temperature levels, whereas the feeding rate of 60 kg/h and the vibration screen height of 6 mm were found to give 100% insect killing efficiency. The resulting head rice yield increased by 0.3-0.7% for a screen height of 8 mm. The quantity of broken rice decreased whereas the total rice quantity did not vary significantly; the milled rice had a whiteness index slightly increased when compared to the reference rice.


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