• Journal of the Korean Society of Food Culture
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• v.12 no.4
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• pp.419-421
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• 1997

Washing water volume of rice for cooking and rice weight for one person per meal in one household were surveyed for confirming pollution by the washing water and total losses by rice washing procedures. The mean size of a family was 4.64 persons and the mean consumption weight of rice per capital per meal was 138.43g. It is used 0.782 L of water for washing the rice per capital share. The washing water of rice was composed of 0.32% of total solid, 0.11% of soluble solid and 1.65% of solid loss to rice, and COD and BOD of it were 2.400 and 3.564 ppm respectively. Based on total population in Korea, 41 miliion, excepting age below 4, total cost for washing water of rice summed up about 1,495 billion won including 8.8 billion won for tap water cost, 11.7 billion won for waste water treatment, and 129 billion for solid loss of rice.

• Membrane Journal
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• v.12 no.3
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• pp.165-170
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• 2002

Membrane process was investigated to recover useful components, such as protein from rice-washing water generated in the production of the washed-rice. The filtration experiments were carried out using not only a dead-end Amicon cell to determine suitable membranes but also a hollow fiber ultrafiltration, spiral wound nanofiltration and reverse osmosis modules for home water purification. Ultrafiltration module(molecular weight cut-off : 10,000 dalton) was not suitable for recovery of useful components or protein in the rice-washing water, but nanofiltration and reverse osmosis modules showed a good performance. in the case of 250% concentration of the rice-washing water contained about 9% protein the proteins in concentrates of nanofiltration and reverse osmosis were 18% and 22%, which were about 2 and 2.4 times higher protein concentrations than those of feed, respectively.

• Korean journal of food and cookery science
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• v.16 no.5
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• pp.410-415
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• 2000

This study was performed to study tile organophosphorus pesticides residues removal effect of rice and Korean cabbage. Four organophosphorus pesticides(EPN, diazinon, fenithrithion, phenthoate) were artificially added to rice and Korean cabbage. Then they were washed with water and cooked differently to analyze the amount of pesticides residues reduced. The result of the study were as following; 1. The removal rate of pesticides residue on rice was 15.5∼35.4% an[ the amount of washing water was more influential in removal rate than number of washing. 2. The removal rate of pesticides residues through cooking processes after rice washing was 72.1∼77.8%. 3. The removal rate of pesticides residues through washing and cooking processes on the Korean cabbage were 18.4∼41.0%, 22.8∼92.7%. 4. As the amount of washing water of Korean cabbage increase, pesticides removal effect was higher. 5. Squeezing out the washed water from the cabbage increased pesticides removal rate.

• Agricultural and Biosystems Engineering
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• v.5 no.2
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• pp.60-63
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• 2004

Demand for development of processing systems for pre-washed rice and propagation of the systems has recently been on the rise, because rice-cooking requires watering 15 times the rice quantity to cook, as in case of the regular rice currently being circulated in Korean market, in addition to paying the trouble of washing it for cooking, and besides the milky turbid water coming from the rice-washing contributes to water contamination. In this study, therefore, a processing system for pre-washed rice was designed and built with rice surface polishing devices that adopted abrading and airing methods, an electrostatic method and a method using a fine watering, to conduct its performance test. The result showed that turbidity of the wash water, which is the base to determine the pre-washed rice standard, turned out 47.33 ppm and 48.00 ppm respectively for 800 kg/hr and 1,000 kg/hr supplies, which meets the standard for the processing system free from rice-washing for cooking. The quantity of watering at this experiment was only 0.43 times the rice, thus resulting in curtailment of process-watering by approximately $69\%$ compared with the existing wet-type pre-washed rice processing system popular in Korean market.

• Food Science and Preservation
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• v.30 no.3
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• pp.472-482
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• 2023

This study used gas chromatography combined with the microelectron capture detection method to determine the most effective washing and cooking methods for removing isoprothiolane from rice. The initial isoprothiolane concentrations in brown and polished rice, before washing, were 17.03 mg/kg and 1.67 mg/kg, respectively. Residual concentrations declined with more washing cycles (19.3-59.3% for brown rice; 43.1-66.5% for polished rice); and by increasing the temperature of the washing water from 5℃ to 40℃ (56.6-63.1% for brown rice; 67.1-74.9% for polished rice). Hand-washing samples using gentle stirring or harsh rubbing reduced pesticide concentrations by 63.1-71.6% for brown rice, versus 75.4-87.4% for polished rice. Reduction in isoprothiolane concentrations varied based on the rice cooker type and whether the rice was pre-soaked. Immediate cooking using an electric- or pressure-cooker showed 78.5% and 78.4% reduction in brown rice, compared with 94.0% and 94.0% for polished rice, respectively. Pre-cooking immersion for 30 min showed similar reductions of 83.4% and 83.4% in brown rice, versus 95.8% and 95.8% in polished rice. The results of this study suggest that the most effective method for removing residual isoprothiolane from both brown rice and polished rice was to wash six times (with vigorous rubbing during the 2nd and 3rd washing) in 7-fold water at 40℃, followed by immersion for 30 min before cooking. Regardless of the type of rice cooker, heating is sufficient to remove an average of 83.4% and 95.8% of isoprothiolane from brown rice and polished rice, respectively.

• Journal of Food Hygiene and Safety
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• v.14 no.1
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• pp.9-16
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• 1999

Effect of storage temperature, washing, and cooking on postharvest-treated pesticide residues in polished rice was investigated. After being treated with each 500 mg/kg of captan, carbaryl, phenthoate, fenthion, fenitrothion, chlorpyriphos-methyl, pirimiphos-methyl, the polished rice was stored for 8 weeks at 4 and 3$0^{\circ}C$, respectively. The penetation rate of carbaryl was the highest as 27.5% and the others, 13 to 18%. The half lives of pesticide residues were estimated as 30 to 230 weeks at 4$^{\circ}C$, but 1 to 12 weeks at 3$0^{\circ}C$. The residues were reduced faster at 3$0^{\circ}C$ than at 4$^{\circ}C$. The half lives of pesticide residues by water washing were estimated as 0.7 to 4.6 trials and the removed with the washing trials. The residues of captan and carbaryl in cooked rice were removed 100 and 98%, respectively, comparing to initial residues concentration in treated rice but those of other 5 pesticides were removed 80%.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.506-512
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• 2006

We investigated changes in the physicochemical characteristics and functional components of the Saengsik cereal grains-milled rice, brown rice, glutinous rice, and barley- by washing with electrolyzed water. There were no changes in the composition of all cereal grains that was dried with hot-air and freeze-dried after being washed with electrolyzed water. The L and a values were not affected by drying in milled rice, brown rice, glutinous rice, or barley, but the b value increased in milled rice and glutinous rice-this increase was greater with hot-air drying than with freeze-drying. The dietary fiber content of the all cereals increased with hot-air drying. The niacin content decreased in all cereals; the extent of this change was greater with hot-air drying than with freeze-drying. The ${\beta}-glucan$ content of barley was higher in samples that underwent freeze-drying than in those treated by hot-air drying, but was not affected by washing with electrolyzed water. Thus, other than a change in color for milled and glutinous rice, no changes in the physicochemical characteristics and functional components these products were observed with freeze-drying. Data indicate that the electrolyzed water washing could be effectively used as pasteurization step in the uncooked cereal grains.

• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.45-51
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• 2014

In accordance with the view on remediated soil as a resource, this study assessed the applicability of soil washing with the neutral phosphate for remediation of arsenic (As)-contaminated soil. Three soil samples of different land uses (i.e., rice paddy, upland field and forest land) were collected from the study site, and the aqua regia-extractable As concentrations were 59.2, 30.8 and 53.1 mg/kg, respectively. Among the neutral phosphate reagents, ammonium phosphate showed the highest As washing efficiency. The optimized washing condition was 2-hr washing with 0.5M ammonium phosphate solution (pH 6) and soil to liquid ratio of 1 : 5. The extraction efficiencies of As did not guarantee the residual soil As concentrations to satisfy the Korea soil regulatory level (i.e., Worrisome level) in the three soil samples. To enhance washing efficiency, the As-contaminated soil was submerged in washing solution (1 : 1, w/v) for 24 hr and 1-hr washing with 0.5M ammonium phosphate solution was tested. As extraction efficiencies of 36.1 (rice paddy), 21.4 (upland field) and 26.4% (forest land) were attained, which satisfied the Worrisome level for Region 1 (25 mg/kg of As) in rice paddy, but not in upland field and forest land.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.77-80
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• 2002

A simple method for sporangial formation of the rice downy mildew pathogen, Sclerophthora macrospora, on infected leaf tissues was developed to facilitate diagnosis of the disease. Freshly infected young leaves showing whitish to yellowish small spots were selected and cut into small pieces about 2-3 cm in length. About 10-20 pieces were surface sterilized in a 100 ml Duran bottle with 40 ml of 70% ethanol by vigorous shaking for 30 seconds. After washing three times with distilled water, the leaf cuts were submerged in 10 ml of Millipore-filtered paddy water and incubated at $20^{\circ}C$ in the dark. After 8-10 h of incubation, the bottle was vigorously agitated on a vortex mixer, Aliquot amount of the suspension, 0.1-1.0 m1, was spread on a slide glass and examined under a light microscope at 50 or 100x magnification. It was found that light and 1% NaClO strongly inhibit sporangial formation of S. macrospora. Meanwhile, the use of freshly infected young loaves and washing with 70% ethanol stimulated sporangial formation of the fungus on rice leaves.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.10a
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• pp.209.1-209
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• 1978

Treatment of domestic sewage discharged from big cafeteria kitchen, especially rice-washing water, was examined by the use of activated sludge process and phytoplankton cultivation. Only with a activated sludge process COD value decreased from around 1000 mg/ι to 100 mg/ι, but nutrients, such as nitrogen and phosphate could not be removed sufficiently phytoplankton cultivation in combination with a activate sludge process could decrease COD value down to 50 mg/ι and nutrients values were also reduced substantially. However, the initial concentration of 20 mg/ι in the rice-washing water could not be removed completely without addition of activated sludge as a nitrogen source.