Relating Rough Rice Moisture Content Removal and Tempering Duration to Head Rice Yield Reduction

2005 ◽  
Author(s):  
D. A. Schluterman and T. J. Siebenmorgen
Keyword(s):  
Moisture Content ◽  
Rice Yield ◽  
Yield Reduction ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield

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 Post-Drying Tempering of Rice on Minimizing Kernel Fissuring and Maximizing Moisture Removal

2021 ◽  
Vol 65 (1) ◽  
pp. 1-9
Author(s):  
Zephania Odek ◽  
Terry J. Siebenmorgen ◽  
Andronikos Mauromoustakos ◽  
Griffiths G. Atungulu
Keyword(s):  
Rice Yield ◽  
Yield Reduction ◽  
List Type ◽  
Humidity Ratio ◽  
Percentage Points ◽  
X Ray Imaging ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield ◽  
Rice Drying

HighlightsMore moisture can be removed in a single drying pass without severely fissuring kernels when samples are tempered than when immediately cooled without tempering.Tempering rice kernels immediately after drying can reduce the percentage of fissured kernels by up to half of that when kernels are immediately cooled without tempering.Abstract. Improper rice drying results in kernel fissuring, leading to head rice yield reduction due to breakage during milling. The objective of this study was to determine the percentage points (pp) of moisture content (MC) reduction that can be achieved in a single drying pass without significantly fissuring kernels. Long-grain rough rice of cultivars CL XL745 and Diamond at initial MCs of 18%, 17%, 16%, 15%, and 14% were dried using air at 45°C/20% relative humidity (RH), 50°C/15% RH, 55°C/12% RH, 60°C/10% RH, and 65°C/8% RH to MCs of 17%, 16%, 15%, 14%, 13%, or 12% with and without post-drying tempering. All temperature/RH combinations resulted in a humidity ratio of 0.012 kg water kg-1 dry air. Tempering was conducted at the drying air temperature for 4 h. The resulting samples achieved between 1 and 7 pp of MC reduction in a single drying pass. The pp of MC reduction that can be attained in a single drying pass without causing significant fissuring varied across the cultivars tested. Generally, ~2 pp of MC reduction was achieved in a single drying pass for CL XL745 and ~4 pp for Diamond without causing adverse fissuring when samples were not tempered after drying. However, with tempering, ~3.5 pp of MC reduction was achieved in a single drying pass for CL XL745 and ~5.5 pp for Diamond without causing significant fissuring. However, these amounts varied depending on the drying air conditions and initial MC. For both cultivars, tempering immediately after drying reduced the fissured kernel percentage by up to half of that when the kernels were not tempered. These findings quantify the importance of rice tempering and provide information on how much moisture can be safely removed in a single drying pass. Such findings may be applied to different dryer types to reduce fissuring due to drying, thereby minimizing head rice yield reductions. Keywords: Drying, Glass transition, Rice quality, Single-pass drying, X-ray imaging.

Rice cultivar response to sublethal concentrations of glyphosate and paraquat late in the season

2020 ◽  
pp. 1-7
Author(s):  
Justin McCoy ◽  
Bobby Golden ◽  
Jason Bond ◽  
Darrin Dodds ◽  
Taghi Bararpour ◽  
...  
Keyword(s):  
Grain Yield ◽  
Growth Stage ◽  
Rice Yield ◽  
Yield Reduction ◽  
Rice Grain ◽  
Rice Cultivars ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield ◽  
Sublethal Concentrations

Abstract Differential tolerance may be observed among rice cultivars with desiccant exposure events during rice reproduction and ripening. Five field studies were established at the Mississippi State University Delta Research and Extension Center in Stoneville, MS, to determine the effects of exposure to sublethal concentrations of common desiccants across multiple rice cultivars. Rice cultivars in the study were ‘CLXL745’, ‘XL753’, ‘CL163’, ‘Rex’, and ‘Jupiter’. Desiccant treatments included no desiccant, paraquat, or glyphosate and were applied at the 50% heading growth stage respective to cultivar. Differential injury estimates among cultivars and desiccant treatments was observed when glyphosate or paraquat was applied at 50% heading. Injury from glyphosate at 50% heading was nondetectable across all cultivars. However, injury following paraquat applications was >7% across all rating intervals and cultivars. Hybrid cultivars exhibited less injury with paraquat applications than the inbred cultivars in the study. Rice following exposure to glyphosate or paraquat at 50% heading growth stage produced rough rice grain yield decreases ranging from 0% to 20% and 9% to 21%, respectively. Rough rice grain yield decreases were observed across all cultivars following paraquat exposure, and all inbred cultivars following glyphosate exposure. Across desiccant treatment, head rice yield was reduced in three of five cultivars in the study. When pooled across cultivar, paraquat applications cause a head rice yield reduction of 10%, whereas rice yield following glyphosate application remained >95%. Although differential tolerance among cultivars to paraquat or glyphosate exposure was observed, impacts on grain quality coupled with yield reductions suggests extreme rice sensitivity to exposure to sublethal concentrations of these desiccants at the 50% heading growth stage.

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.

Exploration of Rough Rice Head Yield Subjected to Drying and Retention Durations in a Fluidized Bed System

2018 ◽  
Vol 34 (5) ◽  
pp. 877-885 ◽  
Author(s):  
Kaushik Luthra ◽  
Sammy Sadaka ◽  
Griffiths G Atungulu
Keyword(s):  
Thermal Stress ◽  
Energy Consumption ◽  
Moisture Content ◽  
Fluidized Bed ◽  
Rice Yield ◽  
Retention Period ◽  
Fluidized Bed Dryer ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield

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.

scholarly journals Method of producing parboiled rice without steam by fluidized bed dryer

2020 ◽  
Vol 187 ◽  
pp. 01002
Author(s):  
Asadayuth Mitsiri ◽  
Somkiat Prachayawarakorn ◽  
Sakamon Devahastin ◽  
Wathanyoo Rordprapat ◽  
Somchart Soponronnarit
Keyword(s):  
Moisture Content ◽  
Fluidized Bed ◽  
Rice Yield ◽  
Experimental Result ◽  
Rice Starch ◽  
Parboiled Rice ◽  
Starch Gelatinization ◽  
Fluidized Bed Dryer ◽  
Head Rice ◽  
Head Rice Yield

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.

X-Ray Detection of Fissures in Rough Rice Kernels

2017 ◽  
Vol 33 (5) ◽  
pp. 721-728 ◽  
Author(s):  
Zephania R. Odek ◽  
Bhagwati Prakash ◽  
Terry J. Siebenmorgen
Keyword(s):  
Rice Yield ◽  
X Rays ◽  
Milled Rice ◽  
Substantial Impact ◽  
X Ray ◽  
X Ray Imaging ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield ◽  
Rice Drying

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.

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