• Food Science of Animal Resources
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• v.30 no.5
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• pp.773-779
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• 2010

The present study was designed to determine the physicochemical properties of yam (Dioscorea) solution fermented by L. bulgaricus, the protective effect of fermented Dioscorea opposita Thunb. on stomach lesions, and the possibility of its application to fermented dairy products. When the concentration of yam increased, the pH increased in raw powder samples but not in extracted powder samples. In 6% raw powder containing the sample, the viable cell counts showed a dramatic increase, whereas those in extracted yam powder significantly decreased in all concentrations during 32 h of fermentation. The viscosity of extracted yam powder showed a lower value than that of raw powder, which was maintained throughout the fermentation. The solution of Dioscorea opposita Thunb. raw powder showed a significantly higher allantoin content compared with the extracted powder (p<0.05). At 2% of added Dioscorea opposita Thunb., 0.65 mg/mL was contained in both samples; however, when 6% of Dioscorea opposita Thunb. was added, the amount of diosgenin increased up to 1.9 mg/mL. When 200 mg of powder/kg body wt. was injected, gastric lesions were apparently reduced compared with those of control rats. With 100 mg/kg body wt. injected into rats, the protective effect was a little lower than that in 200 mg/kg body wt. Based on these data, the present study indicated that yam powder fermented by L. bulgaricus showed a protective effect on gastric lesions in rats; therefore, it may be included as an added ingredient in yogurt manufacture.

• Journal of Dairy Science and Biotechnology
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• v.30 no.2
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• pp.69-74
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• 2012

This study was performed to determine by the ability of the mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus to ferment Dioscorea opposita Thunb. (yam) and to evaluate the nutraceutical value of fermented yam. The titratable acidity (TA) value increased from 2 to 6% with increased concentrations in both raw yam and extracted lactic acid bacteria (LAB) fermented yam (LFY). The viable cell counts and the allantoin and diosgenin contents were higher in raw LFY at large concentrations (6%) than in extracted LFY samples at all fermentation periods up to 32 h. Based on these data, it confirmed that raw yam fermented by the combination culture of L. bulgaricus and S. thermophilus for various fermentation periods favors the symbiotic growth of LAB and results in higher nutraceutical content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.297-300
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• 2002

Endogenous ABA and batatasins were first quantified in the stored tubers and bulbils of the Chinese yam, Dioscorea opposita Thunb. cv. 'Tsukune' by GC-MS with comparison of internal standard, and sugar content was also analyzed by HPLC with comparison of external standard. Endogenous ABA content in stored tubers and bulbils was rapidly decreased as storage period prolonged. ABA content of the bulbils was always higher than that of tuber during storage periods. All batatasins of stored tubers and bulbils at 30 days after storage decreased steadily compared to 120 days after storage. On the contrary, batatasin-Ⅲ of the stored tuber and bulbils was only decreased at 60 days after storage. In Dioscorea opposita Thunb. cv. 'Tsukune' like D. japonica, D. alata, and D. bulbifera, may be controlled by endogenous batatasins and ABA, In these compounds, batatasins rather than ABA might be closely related to dormancy-inducing compound during dormancy of the Chinese yam, Dioscorea opposita Thunb. cv. Tsukune.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.250-254
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• 2011

The study was carried out to evaluate the affect of proton beam radiation on production of bulbil and tuber including change of endogenous gibberellins, of Dioscorea opposita Thunb. The yield of bulbils and tubers from non- and irradiated D. opposita Thunb at doses of 5, 10, 15 and 20 Gy were determined. Endogenous gibberellins were also quantified by GC/MS analysis. D. opposita tubers irradiated at 15 Gy produced higher bulbil production than non-irradiated plants. Enlarged bulbil (above size diameter 4 mm) was significantly increased at 15 Gy. Bioactive endogenous $GA_4$ was dominant in bulbils and tubers irradiated with proton beam rather than $GA_1$. Major gibberellins biosynthetic pathways in bulbils and tubers of D. opposita plants were non C-13 hydroxylation route. From the results of this study, 15 Gy proton beam radiation was suggested as an optimal dose that can produce high amounts of bulbil for mass production of D. opposita plant.

• Korean Journal of Medicinal Crop Science
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• v.7 no.3
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• pp.167-171
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• 1999

This experiment was conducted to determine effects of trenching depth on characteristics and yield of tubers in Chinese yam (Dioscorea opposita Thunb). Self-propelled trencher, ‘NF-827H’ produced by KAWABE company, was used for trenching. When trenched, tuber's length and weight were longer and heavier, tuber's shape was better, and marketable tuber yield was remarkably increased than those of conventional plowing and soil preparation by a tractor. The size and yield of tubers were greatly enhanced by trenching in long-tuber variety than that in short-tuber variety. The depth of trenching is recommended to be more than 60cm for short-tuber variety and more than 80cm for long-tuber variety considering the size, shape and yield of the tllbers.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.151.1-151
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• 2003

Chinese yam(D. opposita Thunb. cv. Jang-Ma) plants showing necrotic mosaic symptom were collected from their growing fields in Andong, Korea. Electron microscoptic examination of negatively stained preparations showed filamentous particles of 660nm in length. The virues purified partially were used to isolate Viral RNA as template for RT-PCR to amplify the CP gene with ChYNMV specific and oligo dT primers. Amino acids sequeces revealed that the viruses shared 99.3％ similarity with ChYNMV(AB044386) which was known as the member of macluravirus. So the viruses from Chinese yam(D. opposita Thunb. cv. Jang-Ma) plants were identified as ChYNMV. Comparing the amino aced sequences of ChYNMV strains with other macluraviruses such as CdMV, NLV and MacMV revealed that N-terminal was the most variable region and conserved regions were present within the genus Macluravirus.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.198-202
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• 2009

The starch properties of two chinese yams were evaluated in this study. Amylose content ranged 13.5% to 19.3%. The swelling power of starches varied 10.98% to 11.43%. Water binding capacity in chinese yam starches ranged 93.46% to 107.21%, high WBC was observed in Ma 1. The onset temperature (To) of two chinese yam starches ranged 62.9 to $75.0^{\circ}C$, peak temperature (Tp) ranged 76.2 to $84.7^{\circ}C$. The PHI(peak height index) was about 4-fold higher in Anwon cultivar than in Ma 1 cultivar. SEM revealed that starches has a presence of large oval or spherical to small irregular-shape granules. Starch granule size ranged 15.23 to 15.52 ${\mu}m$, showing a typical C-type X-ray pattern.

• Korean Journal of Medicinal Crop Science
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• v.8 no.2
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• pp.89-93
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• 2000

This experiment was conducted to investigate the effects of soil texture on agronomic characteristics and tuber yield in chinese yam (Dioscorea opposita Thunb). Tuber length and weight was greater and tuber shape was much better in sandy loam and loam soil than in sandy or clay loam soil. In loam and sandy loam soil, fresh tuber yield was increased by $21{\sim}27%$ in short-tuber type and 6% in long-tuber type, and large tubers yield (above 260g) was increased by $45{\sim}55%$ in short-tuber type and $20{\sim}22%$ in long-tuber type compared to those in sandy soil. There was no differences in large tuber yield at the 5% level of significance between loam and sandy loam soil. Malformation of tuber with bifurcation was extremely increased in sandy soil, and tuber diameter of long-tuber type was decreased in clay loam soil compared to those of the other soil texture.

• Korean Journal of Medicinal Crop Science
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• v.20 no.3
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• pp.190-194
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• 2012

Shoot tips of chinese yam (Dioscorea opposita Thunb.) were cultured on MS medium containing 0.5 mg/L BA to produce micro-tubers in vitro. To stimulate the formation of shoots and micro-tubers, and produce large micro-tubers, the sections of micro-tubers were cultured on MS media with BA and IAA. The shoot multiplication, and the micro-tuber formation and growth were very effective on the media containing 2.0 mg/L BA and 0.5~1.0 mg/L IAA. Sucrose added to MS medium with 2.0 mg/L BA and 0.5 mg/L IAA to stimulate more micro-tuber growth. The medium added 50 g/L sucrose was very effective in the increase of plant fresh weight and micro-tuber growth. After 4 weeks' culture of micro-tuber sections on the medium with 2.0 mg/L BA, 0.5 mg/L IAA and 50 g/L sucrose, the liquid media were added into the same vessels. The micro-tuber growth was stimulated remarkably by the addition of liquid medium. The addition of 25 $m{\ell}$ liquid medium containing 10 g/L activated charcoal, 3x MS salts and 250 g/L sucrose was the most effective in micro-tuber growth.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.208-213
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• 2011

This study was carried out to determine the effect of medium solidity, salt strength, sugar and nitrogen sources, and pH levels on in vitro multiplication of pathogen-free yam (Dioscorea opposita Thunb.). Liquid medium was more effective in the growth of plant height, fresh weight, and formation of microbulb than the solid medium. Optimal condition for plant fresh weight, growth, and multiplication axillary bud was in 1MS salt strength with 60 $g{\cdot}L^{-1}$ sucrose and half strength of $KNO_3$. Optimal condition for microbulb formation was $\frac{1}{2}$ MS salt strength supplemented with glucose 60 $g{\cdot}L^{-1}$ and half strength of $KNO_3$. The number of leaves and nodes were sharply increased from 2 to 5 weeks, whereas plant fresh weight was steadily increased from 3 to 11 weeks after inoculation. Microbulbs were formed at 2 weeks after inoculation and continuously increased until 12 weeks.