• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.4
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• pp.345-350
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• 1991

Rough rice samples of Chucheongbyeo, Bongkwangbyeo and Hwaseongbyeo were collected by the National Agricultural Products Inspection Office. Drying methods of rough rice were sun drying and forced ventilation drying by an oven dryer and temperature of the oven dryer was set to 43, 60, 70, or 8$0^{\circ}C$. Moisture content of samples was reduced from ca. 20% to 15% at the end of drying, and additionally to 12.5 % for the drying at 8$0^{\circ}C$. Characteristics related to rice grain quality, milling recovery, ratio of broken and cracked rices, percentage of germination, and sensory scores of the cooked rices were evaluated. Yielding percentage of brown rice and polished rice remarkably decreased by drying at 8$0^{\circ}C$. Percentages of cracked rice and broken rice were within the criterion of the second grade government brown rice (20%) only in the sun dried and the rices dried at 43$^{\circ}C$, on the basis of damaged rice, opaque kernel rice and colored rice. Broken rice percentage of the polished rice was within the criterion for the standard of government rice (5%) in the sun dried and the rices dried at 43$^{\circ}C$. Germination percentage of rough rice was higher than 80% in sun drying and drying at 43$^{\circ}C$, but remarkably decreased by drying rice at 6$0^{\circ}C$ and over. Sensory palatability of the cooked rice decreased with increase in drying temperature. The present governmental method of judging rough rice on the basis of moisture content and appearance of the rough rice appears to be improved to include the ratio of broken and cracked rices.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47
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• pp.15-32
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• 2002

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s-1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great progress and success was obtained in development of high-quality japonica cultivars and quality evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice cultivars and special rices adaptable for food processing such as large kernel, chalky endosperm, aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer, Recently, new special rices such as extremely low-amylose dull or opaque non-glutinous endosperm mutants were developed. Also, a high-lysine rice variety was developed for higher nutritional utility. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and texture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak, hot paste and consistency viscosities of viscosities with year difference. The high-quality rice variety "IIpumbyeo" showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic microscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high probability of determination. The $\alpha$-amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were IIpumbyeo, Chucheongyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tonsil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, showed the relatively fast deterioration of 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 rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice breed. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large grain rices showed better suitability far fermentation and brewing. The glutinous rice were classified into nine different varietal groups based on various physicochemical and structural characteristics of endosperm. There was some close associations among these grain properties and large varietal difference in suitability to various traditional food processing. Our breeding efforts on improvement of rice quality for high palatability and processing utility or value-adding products in the future should focus on not only continuous enhancement of marketing and eating qualities but also the diversification in morphological, physicochemical and nutritional characteristics of rice grain suitable for processing various value-added rice foods.ice foods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.37-43
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• 2008

Recent consumption of germinated brown rice is increasing due to its health-beneficial effects. To clarify germination-dependent changes in functional compound contents, 5 different types of (ordinary, glutinous, green-kerneled, red-colored and black-colored) rices were selected and their pre- and post-germination content changes in vitamin E (${\alpha}-$, ${\beta}-$, ${\gamma}-tocopherols$ and ${\alpha}-$, ${\gamma}-$, ${\delta}-tocotrienols$), squalene, and phytosterols (campesterol, stigmasterol, sitosterol) were evaluated. In the case of vitamin E isomer contents, germination generally resulted in decreasing tendency around 10% in most isomers as well as in total tocopherol and tocotrienol contents in all types of rices. In the case of squalene, significant increase could be observed in glutinous rice (by 31%), while other types of rices exhibited no changes or slight reduction by germination. Regarding stigmasterol contents, all tested types of germinated brown rice exhibited significant increment by 19 to 27% compared to nongerminated cases, except for green colored-rice which showed statistically not significant 5% increment. No changes or slight reductions, however, could be observed in campesterol and sitosterol, as well as in total phytosterol contents. As a conclusion, most of tested pharmaceutical compounds exhibited statistically not significant changes except for stigmasterol which were increased by the germination process.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.451-458
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• 2013

The physicochemical properties and cooking qualities of four rice varieties (Goami, Giant-embryonic rice, Baegjinju, Aranghyangchal) which grown under ecofriendly farming as development of material for chronic disease tailored instant rice and porridge, respectively, were investigated. The contents of crude protein, crude lipid and crude fiber were the highest in Goami. The water absorption rate of Aranghyangchal at $85^{\circ}C$ was higher than other rice. However on rice flour, the water absorption rate and solubility of all functional rices at $85^{\circ}C$ were higher than control (brown rice flour). In addition viscosity of all functional rices at $100^{\circ}C$ were higher than control (brown rice flour). In spite of brown rice, Aranhyangchal showed no significant differences about hardness of Ilpum (white rice). The sensory evaluation was shown that Aranghyangchal was the highest in glossiness, flavor, roasted nutty taste, cohesiveness and overall preference. Although Giant-embryonic rice and Baegjinju were brown rice, overall preference was higher than Ilpum (white rice). These study results were showed that the functional rices could be good to make instant rice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1365-1370
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• 2007

The inhibitory effects of the water and methanol extracts of Jakwangdo and Honghyangmi on the rat microsome lipid peroxidation and growth of four human cancer cells such as HepG2 (liver cancer), SNU-1 (stomach cancer) MCF-7 (breast cancer) and SNU-C4 (colon cancer) were examined. The methanol extracts of red colored rices showed the antioxidant activity and growth inhibitory effects of cancer cells. However, water extracts did not show the activities. Inhibitory activities of methanol extracts of Jakwangdo and Honghyangmi against lipid peroxidation of rat microsome was 80% and 68%, respectively, at the concentration of 1 mg/assay. Jakwangdo methanol extracts showed the highest growth inhibitory activity in MCF-7 cells among the cancer cells tested. The methanol extracts of red colored rices were further fractionated with hexane, chloroform, ethyl acetate and butanol. Both chloroform and hexane fractions showed strong growth inhibitory activity in HepG2 and MCF-7 cells.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.624-630
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• 2004

Functionality changes by germination of giant embryonic rice and pigmented rice were evaluated with focusing on antioxidative activities of 70% ethanolic extracts. Overall, reducing power of giant embryonic rice and pigmented rice was higher than that of normal brown rice, and the germination of rices tend to enhance their reducing powers. In vitro and ex vivo experiments employing linoleic acid peroxidation and rabbit erythrocyte membrane peroxidation systems, respectively, revealed inhibitory effect on lipid peroxidation was highest in pigmented rice, followed by giant embryonic rice, and normal brown rice from high to low order. Superoxide radical-scavenging activity decreased in order of pigmented rice > giant embryonic rice > normal brown rice, and germination also enhanced their superoxide scavenging ability compared to non-germinated controls. Hydroxyl radical-scavenging ability was highest in pigmented rice, followed by giant embryonic rice, and normal brown rice. Despite marked enhancement in hydroxyl radical-scavenging ability of normal brown rice by germination, order of scavenging ability was not altered among germinated rices. Same trend as with in vitro ROS scavenging was observed for ex vivo scavenging potency on ROSs generated by TPA stimulation in HL-60 cells. Germination-associated differential increase in ROS scavenging ability of pigmented rice and giant embryonic rice, characterized by no induction of cytotoxicity, was observed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.705-710
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• 2004

This study was conducted to investigate the difference of antimicrobial activity between $\varepsilon$-polylysine/grapefruit seed extract mixture and $\varepsilon$-polylysine/glyceride mixture against food-borne pathogens. The minimum inhibitory concentration (MIC) of the $\varepsilon$-polylysine/grapefruit seed extract mixture was 100 times lower than that of the $\varepsilon$-polylysine/glyceride mixture. In case of the $\varepsilon$-polylysine/glyceride mixture the MIC of Bacillus cereus (0.1 $\mu$L/mL) and Pseudomonas aeruginosa (0.1 $\mu$L/mL) were lower than that of Escherishia coli (15 $\mu$L/mL). When rices were cooked with the $\varepsilon$-polylysine/glyceride mixture the number of total microbial cell was decreased during storage at 2$0^{\circ}C$ as concentration of the $\varepsilon$-polylysine/glyceride mixture increased. The antimicrobial activity was the highest against Escherishia coli as the concentration of the $\varepsilon$-polylysine/glyceride mixture increased. Sensory terms such as taste, flavor and texture were not significantly different in cooked rices prepared with 0.5% $\varepsilon$-polylysine/glyceride mixture, but there was significantly different in cooked rices prepared with 1% (p＜0.05) in the overall acceptability, indicating that the cooked rice with 0.5% $\varepsilon$-polylysine/glyceride mixture was recommended.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.4
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• pp.499-502
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• 2007

The objective of this study was to determine antioxidant compounds in specialty rice including milled rice, brown rice, red rice, giant embryonic rice, black rice, green rice, and Goami consumed in Korea. The concentrations of total polyphenols (insoluble and soluble polyphenols), phytic acid, and anthocyanin in the samples were measured using spectrophotometric methods and vitamin I analysis was carried out by HPLC. The contents of the total polyphenolic compounds were 565mg/100g for black rice, 405mg/100g for red rice, 140mg/100g for giant embryo rice, 138mg/100g for Goami, 133mg/100g for brown rice, 127mg/100g for green rice, and 66mg/100g for white rice. The black and red rices were significantly high in polyphenolic contents compared with the other rices, apparently due to their intense red-purple color. Black rice, red rice, and Goami showed significantly higher vitamin E and phytic acid contents compared with other rices. Anthocyanins were determined in only black rice (302mg/100g) due to the detection limits of spectrophotometric assay. hlthough vitamin I and anthocyanin contents were relatively lower than polyphenolics among the samples, the specialty rice may contribute to the significant supply of antioxidant compounds to prevent oxidative stress due to the fact that rice is used as a staple food and consumed in large amounts in our diets. The results can be used to increase rice consumption by enhancing consumer awareness on health benefits of the rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.329-329
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• 2017

The study was conducted to investigate the effects of different harvesting time on pasting properties of starch in three colored rices. Seven major parameters of starch pasting properties, peak viscosity (PKV), hot pasting viscosity (HPV), cool pasting viscosity (CPV), setback (CPV minus PKV), breakdown (PKV minus HPV), peak time, and pasting time were determined by Rapid Visco Analyzer. The peak viscosity, hot viscosity, cool viscosity and peak time were influenced by different harvesting times. Pasting time was delayed slightly with prolonged harvesting time in all rice cultivars. Pasting temperature in each rice cultivar differed from each harvesting time, and pasting temperature of the two rice cultivars, Hongjinju and Joseongheugchal, showed the highest at the 40 days after heading and then it decreased at the final harvesting time. With the delay of the harvesting time, peak viscosity, hot viscosity, cool viscosity, setback value and pasting temperature did not exhibit a regular trend depending on their genetic characteristics. Branch chain length distribution of amylopectin was demonstrated a distinct difference among these colored rices. In changes of amylopectin branch chain-length distribution, the amylopectin structure of Hongjinju rice cultivar as affected by different harvesting time, the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant increase in A chains with $DP{\geq}12$ and remarked decrease in long chains $37{\leq}DP$ compared to that of 30, 40, and 50 days after heading. In particular, when harvesting time is delayed the distribution percentage of short chain (A chains with $DP{\geq}12$) was increased except for the rice which harvested 20 days after heading. The similar results were also observed in Sintoheugmi rice cultivar like that of Hongjinju rice cultivar. Otherwise, distribution percentage of the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant decrease in A chains with $DP{\geq}12$ and remarked increase in B chains $13{\leq}DP{\geq}24$ compared to that of 30, 40, and 50 days after heading.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.412-419
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• 1994

This study was carried out to investigate changes of chemical composition in seed, germination percentage, and seedling growth of two F$_1$ hybrid rices(V20A/Cheongcheongbyeo, IR62829A/Cheongcheongbyeo) during germination compared with their parents (V20B, IR62829B and Cheongcheongbyeo) and check variety(Samgangbyeo). F$_1$ hybrid rice showed higher content of free amino acid, inorganic elements, ($P_2O_5$, $K_2$O, MgO) and total sugar, and higher a-amylase activity in brown rice than those of their parents and check variety during germination. Therefore$F_1$hybrid rices showed hybrid vigor in germination percentage at 33 hour and 48 hour after sowing. $F_1$ Hybrid rices also showed /heterosis in seedling growth was different between V20A/Cheongcheongbyeo and IR 62829A/Cheongcheongbyeo. There were positive significant correlation between a-amylase activity and germination percentage, and seedling growth.