RELATING DRYING RATE CONSTANT TO HEAD RICE YIELD REDUCTION OF LONG-GRAIN RICE

1997 ◽  
Vol 40 (4) ◽  
pp. 1133-1139 ◽  
Author(s):  
H. Chen ◽  
T. J. Siebenmorgen ◽  
B. P. Marks
Keyword(s):  
Rate Constant ◽  
Rice Yield ◽  
Yield Reduction ◽  
Drying Rate ◽  
Head Rice ◽  
Head Rice Yield

HEAD RICE YIELD REDUCTION RATES CAUSED BY MOISTURE ADSORPTION

1990 ◽  
Vol 33 (4) ◽  
pp. 1263-1269 ◽  
Author(s):  
M. M. Banaszek ◽  
T. J. Siebenmorgen
Keyword(s):  
Rice Yield ◽  
Yield Reduction ◽  
Moisture Adsorption ◽  
Head Rice ◽  
Head Rice Yield

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.

Effect of Grain Inverters in Cross-Flow Dryers on Kernel Fissuring and Head Rice Yield Reduction

2020 ◽  
Vol 63 (4) ◽  
pp. 1079-1086
Author(s):  
Zephania R. Odek ◽  
Bhagwati Prakash ◽  
Terry J. Siebenmorgen
Keyword(s):  
Rice Yield ◽  
Cross Flow ◽  
Yield Reduction ◽  
List Type ◽  
Limited Information ◽  
Heated Air ◽  
Air Temperatures ◽  
Head Rice ◽  
Head Rice Yield ◽  
Rice Milling

HighlightsGrain inverters minimized fissuring of rice kernels closest to the heated air plenum at plenum air temperatures =55°C.Grain inverters had no effect on rice kernel fissuring across a grain column at plenum air temperatures <55°C.Grain inverters decreased head rice yield reduction of samples dried at plenum air temperatures >55°C but had no effect on head rice yield reduction at plenum air temperatures =55°C.One or two grain inverters in a cross-flow dryer can help reduce kernel fissuring and minimize head rice yield reduction.Abstract. Industrial-scale cross-flow dryers are commonly equipped with grain inverters to facilitate uniform drying across the column thickness, but limited information is available on the effect of grain inverters on rice milling quality. In this study, lab-scale drying experiments were performed to investigate the effect of grain inverters on kernel fissuring and head rice yield reduction. Rice samples of long-grain cultivar Roy J were dried for 60 min at plenum air temperatures of 45°C, 50°C, 55°C, and 60°C. The number of grain inversions during a 60 min drying period were 0, 1, and 2. After drying, a portion of the sample was tempered at a final bulk-rice temperature (heated tempering), while the other portion was tempered at ambient room temperature (ambient tempering). At plenum air temperatures of 55°C or 60°C, grain inversion (1 or 2 inversions) minimized fissuring of kernels closest to the heated-air plenum compared to 0 grain inversion. At 45°C and 50°C, grain inversion did not affect kernel fissuring. Similarly, at plenum air temperatures greater than 55°C for both ambient tempering and heated tempering approaches, 1 or 2 grain inversions significantly minimized head rice yield reductions compared to 0 grain inversion. These findings may be valuable for designing cross-flow dryers by informing decisions on the number of grain inverters needed to reduce fissuring and minimize head rice yield reduction. Keywords: Column dryer, Milling yields, Reversed airflow, Rice quality, Tempering, Turnflow, X-ray imaging.

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.

scholarly journals Effect of temperature and mode of drying on bioactive compounds and quality of germinated parboiled rice

2018 ◽  
Author(s):  
Busarakorn Mahayothee ◽  
Supaporn Klaykruayat ◽  
Marcus Nagle ◽  
Joachim Müller
Keyword(s):  
Bioactive Compounds ◽  
Rice Yield ◽  
Aminobutyric Acid ◽  
Flow Mode ◽  
Gamma Aminobutyric Acid ◽  
Parboiled Rice ◽  
Head Rice ◽  
Through Flow ◽  
Head Rice Yield

Germinated parboiled rice (GPR) is recognized as a functional food because it is rich in bioactive compounds, especially gamma-aminobutyric acid (GABA). GPR was produced by soaking, incubating, steaming, and then drying using a high-precision hot air dryer. The results indicated that air flow mode and drying temperature had significant effects on the quality of GPR. Drying at higher temperatures and shorter times conserved GABA content. Using through-flow mode decreased drying time and prevented color change. However, a slightly lower percentage of head rice yield was observed. Moreover, using through-flow mode negatively affected the hardness loss after cooking.Keywords: Germinated parboiled rice; Drying mode; Gamma-aminobutyric acid; Head rice yield  

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