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        검색결과 28

        21.
        2012.07 서비스 종료(열람 제한)
        Rice(Oryza sativa L.) feeds more than 50% of the world’s population and is one of the most important crops in the world. To evaluate the variation between different rice classfications, genetic diversity amoung a diverse set of rice collection including 59 breedlines, 23 landraces, 18 weedy rices and 35 introductions were analysed using 134 SSR markers located on the 12 chromosomes. In total, 1269 alleles were identified with an average of 9.47 per locus. Of the 1269 alleles, 460 (36.2%) were common, with a frequency of 0.05–0.5; 741 (58.4%) were rare (frequency < 0.05) and 68 (5.4%) were abundant (frequency > 0.5). A relatively high Polymophism information content (PIC) value was detected in landraces with smaller number of accessions than that of breedlines. Model-based structure analysis revealed the presence of six subpopulations, which was essentially consistent with the clustering based on genetic distance. One hundred and eight accessions (80.0%) showed a clear relation to each cluster based on their inferred ancestry value (>70%), while the remaining 27 accessions (15.4%) of which nine from landraces and fifteen from introductions were categorized as admixtures. Landrace and introductions distributed to almost all the six subpopulations whereas most of breedlines distributed to two distinct subpopulations. In conculusion, landraces in the present study showed critical importance in preservation of genetic diversity and rice breeding programs.
        22.
        2011.09 KCI 등재 서비스 종료(열람 제한)
        To characterize phytonutrients, the seeds of 12 purple Perilla (Perilla frutescens var. crispa) accessions collected from Korea and Japan were used for quantitative analysis of tocopherols, phytosterols, squalene and fatty acids. The average tocopherol, squalene and phytosterols contents were 12.2 mg 100g-1 , 3.99 mg 100g-1 and 77.20 mg 100g-1 , respectively. Among 4 tocopherol (T) isomers (α -T, β -T, ~gamma -T, and δ -T), ~gamma -T was present in the highest quantity (11.03 mg 100g-1 ) with the least variation (CV = 13.7%), while β -T was present in lowest quantity (0.25 mg 1100g-1 ). Compared to campesterol (4.36 mg 100g-1 ) and stigmasterol (13.32 mg 100g-1 ), β -sitosterol exhibited higher quantity (59.51 mg 100g-1 ) with 9.5% of variation. The major fatty acids were unsaturated fatty acids such as linolenic (61.5%), linoleic (17.3%), and oleic (9.9%) acids compared to saturated ones: palmitic (7.6%) and stearic (3.7%) acids. When Korean and Japanese accession were compared, almost no difference in content could be observed, while more variation as evaluated by CV (%) could be observed in Japanese accession in most phytonutrients suggesting wider genetic variation of purple Perilla in Japan. Presence of all above-mentioned phytonutrient compounds strongly suggested health beneficial value of purple Perilla seeds.
        23.
        2008.12 KCI 등재 서비스 종료(열람 제한)
        Due to the fact that tocopherols and tocotrienols have antioxidant and anticancer properties, the commercial utilization of unsaponifiable fractions in rice bran is increasing. These nutraceutical compounds, however, are fairly unstable and readily break down when exposed to oxygen or lighting conditions. To compare the relative sensitivity of vit E isomers to heat and oxygen, concentrated unsaponifiable fractions extracted from crude rice bran oil were exposed to various temperature, oxygen (nitrogen-balanced), and bathing solvent conditions and resultant concentration changes in α- and γ-tocopherols (T) and tocotrienols (T3) were evaluated. Each isomer exhibited different heat stability. Among them, α-T3 degraded more rapidly compared to other vit E isomers while α-T was the most stable isomer. Oxygen level also showed significant impact on each isomer's stability where severe reductions of γ-T (by 20%) and γ-T3 (by 29%) were observed under 2% oxygen conditions, while under 0% oxygen conditions no degradation could be observed even after exposure to 95℃ for 4 hours. When various blending solvents were mixed with concentrated unsaponifiable fractions, organic solvents such as isooctane and hexane were more effective in maintaining the stability of γ- T3 compared to edible oils, among which com oil was more efficient than soybean and rice bran oils.
        24.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        Recent consumption of germinated brown rice is increasing due to its health-beneficial effects. To clarify germination-dependent changes in functional compounds, 5 different types of (ordinary, glutinous rice, green-kerneled, red-colored and black-colored) rices were selected and pre- and post-germination vit E (α-, β-, γ-tocopherols and α-, γ-, δ -tocotrienols), squalene, and phytosterols (campesterol, stigmasterol, sitosterol) contents were evaluated. In the case of vit E generally decreasing tendency were observed in most cases, except for δ-tocopherol which increased by 8 to 28% in all types of rices. Significant increase in squalene contents were observed only in glutinous rice (by 31%), while other types of rices exhibited no changes or slight reduction after germination. In all tested rice types, germination significantly increased stigmasterol by 5 to 27%, while no changes or slight reductions in campesterol and sitosterol were observed. In conclusion most of tested functional compounds exhibited statistically not significant or slight changes except for stigmasterol which were increased by the process of producing germinated brown rice.
        25.
        2006.03 KCI 등재 서비스 종료(열람 제한)
        Traditionally fatty acid composition used to be analysed by a GC and the sample preparation process includes lipid extraction from sample and subsequent methyl esters preparation, which are time-consuming and cumbersome. As an alternative, simultaneous extraction/methylation methods are being developed for rapid and simplified sample preparation. To optimize one-step extraction/methylation method for analysis of fatty acid composition in brown rice, various reaction factors such as sample to reaction solution ratio, reaction time and temperature, shaking intensity were changed and resultant fatty acid composition data were evaluated in comparison with previous reports. The ratio of sample weight to reaction solution volume was the most critical factor in that higher sample to reaction solution ratio caused overestimation of palmitic acid and linoleic acid composition, resulting in underestimation of oleic acid. Lower reaction temperature also induced overestimation of linoleic acid and underestimation of oleic acid. Reaction duration and the intensity of shaking prior to and during the reaction, however, caused no significant changes in analysis results. In conclusion, the optimum condition was mixing 5 grains (about 0.2 g) of brown rice with 680~muL of extraction/methylation mixture and 400~muL of heptane, followed by reaction at 80~circC for 2 hours.
        26.
        2004.12 KCI 등재 서비스 종료(열람 제한)
        To understand the postharvest characteristics of soybean sprouts, 5-day-old sprouts were harvested, packed in PE film, and stored at 4, 12, and 20~circC for up to 4 days. In addition, the sprout respiration rate was measured after storage at 4, 8, 12, 16, 20, and 24~circC for up to 20h. During the first day of storage at 20~circC , the sprouts maintained temperature-dependent longitudinal growth, especially of hypocotyl length; hypocotyl and root grew 0.8cm and 0.2cm, respectively. The hypocotyl thickness decreased by 11, 13, and 18~% after 4 days of storage at 4, 12, and 20~circC , respectively. No temperature-dependent differences in fresh weight, dry weight, or water content were found, despite decreases of 3~% over the 4 days of storage. A significant postharvest decrease of 50~% in vitamin C content was observed in the sprouts stored at 20~circC for 3days. Based on the CO2 production rate, the soybean sprouts exhibited an increase in respiration in proportion to the storage temperature; sprouts stored at 8, 12, 16, 20 and 24~circC showed approximately 2, 5, 6, 11, and 17 times, respectively, than the respiration rate of sprouts stored at 4~circC . These results indicate the importance of low temperature storage during market circulation for minimizing the postharvest morphological and nutritional degradation of soybean sprouts.
        27.
        2003.12 서비스 종료(열람 제한)
        To improve industrial scale extraction method for extraction of icariin from Epimedium koreanum Nakai, the yields under different extracting conditions such as solvent, temperature, duration and solvent to plant material weight ratio were compared. Regarding extracting solution, highest extracts and icariin yield could be achieved when 10% EtOH was used. In case of plant material to extracting solvent ratio, no significant differences could be observed from 1/10 to 1/50, indicating 1/10 was the most efficient. Extracting temperature significantly affected extracts and icariin yields in that 90℃ increased the collected extracts and icariin contents up to 29.6% and 0.76%, respectively, compared to 27.2%, 0.33% at 70℃. The yield of extracts was less dependent upon extracting temperature compared to icariin yield. Regarding extraction time, 4 hr and 6 hr resulted in high extracts and icariin yield, respectively. We found extracting Epimedium koreanum Nakai in 10 times volume of 10% EtOH for 4 and 6 hr at 90℃ seem to be relatively efficient methods for extracts and icariin, respectively.
        28.
        1999.12 KCI 등재 서비스 종료(열람 제한)
        The practicality of utilizing chitosan as a natural antimicrobial compound to reduce soybean sprout rot was tested. Domestic and imported soybean seeds were soaked for 6 hours in solutions containing different levels of chitosan and acetic acid (glacial), and cultured at 25~circC for 6 days. In case of domestic seeds, soaking with 1,000ppm chitosan increased germination percentage, hypocotyl thickness, total length, and fresh weight of sprouts by 4%, 5%, 2%, and 1%, respectively. The total sprout yield was increased by chitosan in a concentration-dependent manner in that 1,000ppm chitosan resulted in 8% increment of total yield (7.47kg sprouts/kg seed). Chitosan significantly reduced sprout rot percentage to 7.0% compared to control (13.8%), and consequently enhanced marketable sprout yield by 39%. Compared to domestic seeds, the imported soybean seeds exhibited very low germination percentage regardless of chitosan treatments. Chitosan, nevertheless, consistently induced yield increment and rot decrement in imported soybean sprouts. Although 100ppm acetic acid was effective in reducing sprout rot percentage down to 11.8%, its yield-increasing effects were not as prominent as chitosan. In conclusion, soaking soybean seeds with chitosan seems to be a practical method to enhance the efficiency of soybean sprout production
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