• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.44 no.4
• /
• pp.355-363
• /
• 1999

The experiments were carried out to elucidate the varietal variation of retrogradation in aged cooked rice and its association with some physicochemical properties of milled rice. The fifteen rice materials were selected from forty-three low-amylose japonica and Tongil-type rice cultivars based on palatability and retrogradation of cooked rice stratified by preliminary sensory evaluation of warm and cooled cooked rice. One japonica glutinous rice variety was included for comparison of retrogradation of cooked rice. The $\alpha$-amylase-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The desirable checking time for evaluating the varietal difference in deterioration of aged cooked rice was four hours after storing in room temperature and two hours after preserving in refrigerator based on the largest coefficients of variations in degree of retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were Ilpumbyeo, Chucheongbyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tongil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, showed the relatively fast deterioration of cooked rice. The retrogadation index represented by the percentage of retrogradation difference between warm and cooled cooked rice to original estimates of warm cooked rice was significantly affected by the degree of retrogradation of cooled cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogradation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked nce. The varietal difference in retrogradation of cooked rice can be effectively classified by scatter diagram on the plane of upper two principal components based on some retrogradation properties of cooked rice. The deteriorated structural change in cooled cooked rice by observing through the scanning electron microscope was more conspicuous in the fastly retrograded cooked rice than in the slower one.

• Korean Journal Plant Pathology
• /
• v.1 no.2
• /
• pp.109-114
• /
• 1985

The experiments were conducted to clarify the influence of transplanting date on the occurrence of rice virus in field condition of 1984. The rate of RBSDV (rice black-slreaked dwarf virus) viruliferous vector, smaller brown planthopper (Laodelphax striatellus Fallen), was shown to be $13.6\%$ at the 2nd adult and that of rice stripe virus (RSV) viruliferous was $6.7\%$ at the 2nd adult. The vector in the field was begun to come from May 29, the maximum densities were 19.6 insects per hill on June 13 in cultivar Chucheongbyeo, 19.3 in Nagdongbyeo, 7.4 in Cheongcheongbyeo and 4.9 in Samgangoyes. The number of vectors per hill was inclined to increase by early transplanting. Although the infection of rice virus in nursery bed was not recognized until May 30 transplanting, the nursery infection could be seen from June 10 transplanting. The highest rate of nursery infection with RSV was $4.1\%$ at June 10 transplanting plot, and that of RBSDV was $14.2\%$at June 20 trans planting plot. The infection of rice virus in paddy field was the highest at May 20 transplanting plot, the lowest at July 10 plot. The earlier transplanting, the more severe occurrence of rice viruses. Occurrence of infected plants with RBSDV was shown to increase more rapidly at May 20 and May 30 planting plot than May 10 plots. However, the occurrence of infected plant with RSV was more rapid at May 10 transplanting plot than May 20 and 30.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.48 no.3
• /
• pp.209-215
• /
• 2003

This experiment was conducted to study the varietal and ecological difference of rice in heading date by night illumination. The degree of delay in heading date and days from heading initiation to full heading (DHIF) of rice were in the order of mid-late maturing cultivars (MLC)＞ medium maturing cultivars (MEC) ＞early maturing cultivars (EAC) ＞very early maturing cultivars (VEC). However, the MEC showed significant variation in days to heading; Kwanganbyeo delayed significantly, but Ansanbyeo did not. The comparative sensitivity of different rice ecotypes per lux in delayed heading was 0.09-0.10, 0.14-0.26, 0.16-0.58, and 0.35-0.54 day in VEC, EAC, MEC, and MLC, respectively; the shortest ion Odaebyeo (0.09 day), moderate in Daeanbyeo (0.35 day), and the longest in Kwanganbyeo (0.58 day). Difference of DHFI was 0.-1 day in VEC, -l-2 days in EAC, 0-l6 days in MEC and 6-18 days in MLC under 50-70 lux compared to 2 lux; Daejinbyeo (-1 day), Hwaseongbyeo (6 days), Chucheongbyeo (9 days), Kwanganbyeo (16 days), and Ilpumbyeo (18 days).

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.368-368
• /
• 2017

Rice is the world's three major crops that is the staple food of Asian. Japonica type rice is consumed in Korea. Rice cultivation area decreases steadily. That is affected by decrease of the farm income with the inventory of 1.7 million tons, which is 2 to 3 times more than the optimal amount due to the decrease in the consumption of rice per person and cultivate high yield varieties. In recent years, as income level has improved, interest in health has been high and consumption for health food has been steadily increasing. For health food, rice is added by adding grains such as millet, sorghum, oats, beans and colored rice rather than white rice. In 1997, RDA(Rural Development Administration) developed black rice 'Heuknambyeo', and then 20 varieties were bred until 2017. In CBARES(Chungbuk Agricultural Research and Extension Services), we have developed new rice varieties 'Cheongpungheukchal' in 2010, 'Cheongpungheukhyangchal' in 2014, 'Cheongpungheukchal' is high in farming preference because of high yield. Black rice has high content of GABA and water-soluble phenol, DPPH radical scavenging activity, and consumers are interested in the function in the body. Therefore, functional and antioxidant activities(anthocyanin, total polyphenol, ${\alpha}-glucosidase$ inhibition) and antioxidant activities(ABTs, DPPH) were analyzed by comparing white and black rice. Testing varieties are 'Chucheongbyeo', best quality cultivars 'Daebo' and 'Samgwang' as white rice which are cultivated much in Chungbuk area, and black rice are 10 varieties including 'Cheongpungheukchal', 'Cheongpungheukhyangchal', 'Josaengheukchal' and so on. It has transplanted on 25th May, at CBARES research paddy by 100% fertilizer recommendation rate. Harvesting time was 50 days after heading by varieties, and has researched growth properties, yield and yield components, functional and antioxidant activities. Anthocyanin content was not measured because there was no pigmented in white rice, the highest value of anthocyanin content was 'Shintoheukmi' and in the range of 125.6~249.6mg/100g by black rice varieties. Total polyphenol content was high 'Cheongpungheukchal' and 'Shintoheukmi' and in the range of 96.68~244.34 mg/100g in black rice, white rice lower than blackish rice at 19.84~22.51mg/100g. ${\alpha}-glucosidase$ inhibition was high 'Cheongpungheukchal', 'Cheongpungheukhyangchal' and 'Shintoheukmi' in the rage of 75.87~98.85% by black rice varieties, especially 'Samgwang' was 80.75% and the other white rice was higher than 58~68%.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.311-311
• /
• 2017

The relationships between rice grain filling and air temperature of maturing period in paddy field were analyzed to evaluate the effects of climatic change on rice productivity in Korea. Data of air temperature of 31, 41 and 51 days after heading(DAH) for 11 years from 2002 to 2016 were collected and analyzed to determine the effects on rice yield and yield component related traits of Chucheogbyeo, popular cultivar in Gyeonggi province in Korea. As the results, ripening ratio was closely correlated with the mean of daily maximum temperature (DMAT $r=0.71^*$), the mean of daily temperature difference (DTD, $r=0.67^*$) of 41 DAH and DTD ($0.65^*$) of 51 DAH. Weight of 1,000 paddy rice grains was closely correlated with accumulated sunshine hours (ASH) of 31 ($r=0.84^{**}$), 41 ($r=0.75^{**}$), 51 ($r=0.72^*$) DAH. Brown rice grain weight recovery ratio was closely correlated with DTD ($r=0.76^{**}$) and ASH ($r=0.84^{**}$) of 31 DAH, DMAT ($r=0.75^{**}$, $r=0.79^{**}$), DTD ($r=0.79^{**}$, $r=0.77^{**}$) and ASH ($r=0.81^{**}$, $r=0.79^{**}$) of 41 and 51 DAH. Paddy rice yield was closely correlated with MDT ($r=-0.63^*$) of 31 DAH, mean of daily minimum temperature (DMIT, $r=-0.83^{**}$, $r=-0.70^*$), DTD ($r=0.71^*$, $r=0.62^*$) of 31 and 41 DAH. Brown rice yield was correlated closely with DMIT ($r=-0.86^{**}$, $r=-0.73^*$) and DTD ($r=0.80^{**}$, $r=0.72^*$) of 31, 41 DAH, and DTD ($r=0.69^*$) of 51 DAH. Milled rice yield was correlated closely with DMIT ($r=-86^{**}$, $r=-0.73^*$), DTD ($r=0.79^{**}$, $r=0.71^*$) of 31, 41 DAH, and DTD ($r=0.68^*$) of 51 DAH.

• Korean Journal of Food Science and Technology
• /
• v.28 no.6
• /
• pp.1026-1032
• /
• 1996

The effects of steeping temperature $(7^{\circ},\;15^{\circ},\;20^{\circ}\;and\;30^{\circ}C)$ and steeping time $(2{\sim}14\;hr)$ on the physicochemical properties of milled rice (variety; Chucheongbyeo) were investigated. The pH of the steep water decreased as the steeping time increased, which was more pronounced at higher steeping temperature. The solid loss was about 4.0% during steeping. The contents of protein, fat and ash decreased during steeping, which was greater at elevated temperature. The lightness of rice was slightly increased, and the yellowness was decreased upon steeping. The water-binding capacity of rice was increased during steeping at above $15^{\circ}C$. The slight increase of the swelling power of rice at $80^{\circ}C$ was observed upon steeping. The maximum wavelengh for the rice flour-iodine complex was moved to a higher wavelengh, but X-ray diffraction patterns remained constant regardless the steeping conditions. The pasting properties of rice flour (10%) by amylograph indicated that the peak viscosity increased as the steeping time was increased at all steeping temperatures. The steeping resulted in the greater breakdown and the 1ower setback. The log peak viscosity showed a linear relationship with the steeping time. The activation energy and $Q_{10}$ value for the visciosity increase rate was 2, 320 cal/mole and 1.14, respectively.

• Applied Biological Chemistry
• /
• v.29 no.1
• /
• pp.90-95
• /
• 1986

A comparative study of chemical characteristics, efficacy and relative merits of extruded and coated granules, containing fungicide and insecticide, was conducted under laboratory and field conditions. Probenzole (3-allyloxy-1,2-benzisothiazole 1,1-dioxide) and carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methyl carbamate) were chosen as toxicants for rice blast(Pyricularia oryzae) and brown planthopper (Nilaparvata lugens) control, respectively. Stability of active ingredients in coated granule was superior to the extruded one under accelerated temperature. Active ingredient dissolution of coated one into distilled water showed slow release pattern. Pesticide residues in rice (Oryzae sativa, Chucheongbyeo) shoot applied with extruded one at the dosage of 3kg/10a retained higher levels than those with coated one on two days after application, while the residue levels were a reversed tendency on eight days after application. Efficacy on rice blast exhibited minute differences between the granules, on the other hand efficacy on brown planthopper by coated one was of higher rank than that by extruded one. Production cost of the combined pesticide granule by coating method could be cut down by 6% as compared to extrusion method.

• Applied Biological Chemistry
• /
• v.38 no.6
• /
• pp.554-562
• /
• 1995

Effect of the modification of rice protein by protease and 2-mercaptoethanol on physicochemical and gelatinization properties was investigated for the three cultuvars of rice. Total amylose contents of Chucheongbyeo(japonica type), Chosengtongilbyeo(tongil type, indica x japonica) and IR 36 (indica type) were in the range of $20{\sim}25%$. Total amylose and insoluble amylose content of IR 36 were higher than the others. The differential scanning calorimetric and X-ray diffraction results revealed higher relative crystallinity of IR 36 than the others. Water uptake was increased and amylographic viscosity was significantly decreased by 2-mercaptoethanol treatment. Amylographic viscosity was significantly decreased and hot water-soluble carbohydrate content was increased by protease treatment. The proportions of high molecular weight of soluble carbohydrate fractionated by gel filtration chromatography were increased by protease treatment. These effects were most significant in IR 36. This results suggested that starch gelatinization be accelerated by alteration of the protein with protease and reducing agent.

• Korean Journal of Breeding Science
• /
• v.40 no.4
• /
• pp.394-400
• /
• 2008

Blast resistance of one hundred and thirty-one rice cultivars bred in Korea was tested with thirty Korean isolates and twenty-two Philippines isolates using three screening methods. In the blast nursery conducted in Korea and in the Philippines, average disease index of rice cultivars were 4.6 and 2.2, respectively. Seventy-nine cultivars showed different resistance reaction in Korea and in the Philippines, and 19 cultivars showed the same resistant reaction in two locations. In the seedling test, Korean blast isolates displayed different levels of virulence. 93-093, a Korean isolate, was compatible with 90 cultivars whereas 97-057 showed a compatible reaction with 13 cultivars. Twenty-three cultivars showed high level of resistance against Korean and Philippines isolates but Chucheongbyeo, Heugnambyeo, and Manmibyeo showed susceptible reaction to all blast isolates. Through the sequential planting test in Korea and in the Philippines, Palgongbyeo and Seomjinbyeo displayed durable resistance, and Nagdongbyeo and Gihobyeo showed high level of disease infection over the planting time. These results indicate that blast isolates collected in two countries have different genetic background and number of compatible isolates should be considered in definition the durability of rice cultivar to rice blast.

• Korean journal of applied entomology
• /
• v.25 no.1 s.66
• /
• pp.27-32
• /
• 1986

To establish a method for measuring varietal resistance against rice stem maggot in field and pot, 20 varieties were used in $1981{\sim}1983$. The degree of injured stems by the 1st generation larvae was significantly correlated with that of injured panicles by the 2nd ($r=0.864^{**}$). There was no ovipositional preference in rice stem maggot. The larval mortality after artificial infestation varied widly from 5.6 to 100% in varieties and that of the resistant varieties was high after boring. There was a negative correlation between number of injured leaves and larval mortality after artificial infestation ($'81:r=-0.833^{**},\;'82:r=-0.918^{**}$). It is considered that larval mortality mainly caused by antibiosis and larval mortality 20 days after infestation on rice seedlings is ideal for evaluating the varietal resistance to rice stem maggot. Resistant varieties are Nagdongbyeo, Jinjubyeo and Chucheongbyeo susceptible varieties, Keumgangbyeo, Milyang 23, Baigyangbyeo and Milyang 30.