This study was investigated the quality characteristics and antioxidant of dried Dioscorea bulbifera with various pre-soaking concentrations of oligosaccharide. Dioscorea bulbifera are prepared by additions of 0, 4, 6, 8 and 10% oligosaccharide solution, and dried at 50℃. The effects of pre-soaking percent of Dioscorea bulbifera slices were evaluated by the moisture, soluble solid, pH, titratable acidity, color, browning degree, texture, antioxidant activities and sensory test. According to the percent of pre-soaking oligosaccharide solution was increased, the moisture was increased but soluble solids and titratable acidity were decreased. With respect to the result of colors, Dioscorea bulbifera slices that underwent the 10% pre-soaked process (85.86%) were lighter than control (73.88%). However, the redness and yellowness scores were the lowest than control. The springiness and cohesiveness of texture showed no significant differences among all groups. Gumminess and chewiness of texture results were increased according to per-soaking concentration increase. Also the polyphenol, flavonoid and DPPH (α, α-diphenyl-β-picrylhydrazyl) and ABTS [2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging activities were significantly increased with increasing immersion concentration. The Dioscorea bulbifera slices supplemented with 6% pre-soaking oligosaccharide solution treatment showed the highest total sensory score. The results of our study indicated that when pre-soaking oligosaccharide solution is used to immerse the Dioscorea bulbifera slice, it has browning inhibition and antioxidant effect.

둥근 마는 전북 정읍지역에 주로 재배되고 있으며 숙취해소, 자양강장, 소화촉진, 혈당저하, 변비해소, 피로회복 등 에 이용되고 있다. 주성분으로 전분, 뮤신, 사포닌, 아르기닌 등 특수성분이 많이 들어있고 일반 마에 비해 뮤신, 디오 신, 섬유질이 2.5~3.5배 정도 많이 함유되어 있으나 주로 생과나 분말로 판매되어 꿀, 우유, 요구르트에 섞어 마시거나 즙 등으로 가공 유통이 제한적으로 이용되고 있다. 따라서 본 연구는 둥근 마의 이용성을 높이기 위한 적정 초산발효 조건 선발을 위한 품질특성 변화를 알아보았다. 초산발효를 실시하기 전 알콜 발효를 먼저 실시하여 마 첨가비율을 선발한 결과 마 첨가비율이 높아짐에 따라 당도, 알콜 함량은 감소하였으나 마 20% 첨가 시 알콜 함량 16.5%를 나타 내어 대조구 알콜함량 17% 대비 알콜함량 효율이 우수하였다. 마의 주요성분인 디오신 함량이 0.216 mg/g을 나타내었 으며 관능평가에서도 마 첨가량 20%에서 우수하여 초산발효 시 마 첨가량으로 적정 하였다. 마 초산발효를 위한 알콜 함량 선발시험 결과 알콜 함량 6%에서 총산도 4.79%, 당도 3.6°Bx를 나타내었다. 또한 초산균 선발을 위해 자체 선발 균주 17종을 대상으로 16S rRNA로 동정한 결과 A. pasteurianus 2종을 선발하여 초산균으로 이용한 결과 막걸리에서 분리 동정한 A. pasteurianus 초산균 사용 시 총산도 4.41%, 당도 3.7°Bx, pH 3.34를 나타내어 초산발효 조건으로 우수 하였다.

Root-knot nematode damage was found on yam, Dioscorea bulbifera in Andong Korea. From the root-knots, female nematodes were isolated and subjected to DNA sequence analysis. Sequence of cytochrome oxidase subunit Ⅱ (COII) was analyzed from the genomic DNA of the isolate. COII locus size and sequence of the nematode isolate were similar to those of Meloidogyne javanica or M. incognita. However, an analysis of HinfⅠ restriction site, a species-specific character between these two species, showed that the isolate did not match to either M. javanica or M. incognita.

Background : Dioscorea bulbifera (DB) contain steroidal saponin which has anticancer and anti-inflammatory. DB is a health-functional material used as edible and medical materials. However, DB has not been studied in detail as industrial purposes of fermentation. Methods and Results : D. bulbifera (DB) was fermented by Rhizopus oryzae CN105 for 3 days. Samples were prepared by adding 10% honey to the D. bulbifera (DBH) and honey free D. bulbifera (DB). The pH, total acidity (%) and reducing sugar (%) were investigated. The free sugar and color values related to taste components were analyzed. The pH level decreased while total acidity increased during fermentation. The free sugar and color values related to taste components were analyzed. The content of free sugar in the DB was the highest after 3 days of fermentation. In case DBH, only glucose was the highest after 3 days of fermentation. The content of fructose, sucrose and lactose were decrease during fermentation. Total polyphenol content of DB and DBH was measured by the Folin-Denis method. Total flavonoid content was measured by the Moreno method. Total polyphenol content and flavonoid content was the highest after 1 days of fermentation in both DB and DBH. Conclusion : The results showed that physicochemical components improved during fermentation in DB. But antioxidant activity was the highest after 1 days of fermentation in DB and DBH. These results are indicated that fermented DB can be used as a functional food.

This study was carried out to investigate shelf-life and quality of fresh-cut Dungkunma (Dioscorea bulbifera) in order to elevate utilization of Dungkunma a fresh food. Before vacuum-packaging (in polyethylene/polypropylene film (100μm, 15×20 cm, 75±2 cmHg) and storaging at 2℃, Dungkunma was peeled out and cut to dice type (2.0±0.5 cm3), and then washed and blanched using hot water (at 90±2℃ with 2% NaCl solution for 30 sec). Blanched Dungkunma was pre-dried at room temperature, 40℃ and 50℃ for removing surface water. Each peeled dice Dungkunma was packed 50 g in polyethylene/polypropylene film (100 μm, 15×20 cm) with vacuum treatment (75±2 cmHg) and stored at 2℃ for 90 days. Hardness and adhesiveness of Dungkunma blanched by 2% NaCl and pre-dried at 50℃ (SB50) were the highest, but changes were the least during storage. Lightness and yellowness of stored Dungkunma in all treatments decreased slightly while redness increased during storage. Changes of color of SB50 was the least. Total concentration of aerobic bacteria in SB50 was 1.88±0.18 log CFU/g during 90 days and E. coli was detected in all treatments during whole storage periods. Dioscin and allantoin contents of SB50 were virtually unchanged during the storage. Consequently, the results of this study suggest that vacuum packaged Dungkunma after blanching using 2% NaCl solution could be effective to prolong the quality of fresh-cut Dungkunma.

Background : Dungkunma (Dioscorea bulbifera, commonly known as the air potato, air yam, bitter yam, cheeky yam, potato yam) is a species of true yam in the yam family, and has been used as folk remedy to treat conjunctivitis, diarrhea and dysentery, etc. This study was carried out to investigate shelf-life and quality of fresh-cut Dungkunma (Dioscorea bulbifera) in order to elevate utilization of Dungkunma as fresh food. Methods and Results : Before vacuum-packaging (in polyethylene/polypropylene film (100 ㎛, 15 × 20 ㎝, 75 ± 2 ㎝Hg) and storage at 2℃, Dungkunma were peeled out and cut to dice type (2.0 ± 0.5 ㎤), and then washed and blanched (30 sec at 90 ± 2℃ hot water and 2% NaCl solution) and pre-dried at room temperature, 40℃ and 50℃ for removing surface water. Each peeled dice Dungkunma were packed 50 g in polyethylene/polypropylene film (100 ㎛, 15 × 20 ㎝) with vacuum treatment (75 ± 2 ㎝Hg) and stored at 2℃ for 90 days. Hardness and adhesiveness of Dungkunma blanched by 2% NaCl and pre-dried at 50℃ (SB50) was the highest and increased and decreased, respectively, but changes was the least during storage. Lightness and yellowness of stored Dungkunma in all treatments decreased slightly and redness increased during storage but changes of color was the least at SB50. On vacuum packing, SB50 showed 1.88 log CFU/g of total aerobic bacteria during 90 days, and E. coliwas detected in all treatments during whole storage periods. Dioscin and allantoin content of SB50 was virtually unchanged during the storage. Conclusion : Consequently, the results of this study suggest that vacuum packaged Dungkunma after blanching at 2% NaCl could be effective to prolong the quality of fresh-cut Dungkunma and could be easily used.

Background : Unlike Dioscorea japonica or Dioscore opposita, Dioscore alata is a high-temperature crop mainly cultivated in Africa and subtropical regions. Due to recent climate change, its cultivation area is expanding in Korea. In 2016, the Institute for Bioresource Research clarified optimal harvesting stage to increase its tuber yield and ensure safe storability. Methods and Results : As the seed-tubers for this study, Dioscorea alata tubers were cut into a size of 50 g, disinfected with lime powder, dentated on the seed bed with electrothermal wire installed on March 20th, and then planted on the main field on April 15th. The planting distance was 120 ㎝ in width, where the furrows of 90 ㎝ were cladded with black vinyl, in two rows with a column spacing of 25 ㎝. The amounts of applied fertilizers were 2,000 ㎏ compost, 34 ㎏ N2, 28 ㎏ P2O6, and 28 ㎏ K2O. The compost and P2O5 were used in full, where as N2 and K2O were used as original fertilizer 14 (10 ㎏) and additional fertilizer 20 (18 ㎏), respectively. The crop was harvested in six times from September 20th to November 9th, in an interval of 10 days. While harvesting, the ground fresh weight yield and underground tuber yield were investigated. The underground tuber yield was 836, 1,744 and 2,975 ㎏ low at the early harvests on September 20th, 30th, and October 10th, respectively, while it was 3,622, 3,828, 3,818 ㎏ high on October 20th, 30th, and November 9th, respectively. The ground fresh weight yield remained the same. To clarify tuber storability by harvest time, they were stored at 15℃after harvest, and then healthy and corrupt tubers were studied on March 23th. The corruption ratio by harvest time was highest at 39.1% and 29.3% on October 30th and November 9th, respectively, when frost and low temperature damaged harvest. It was 59.0% and 42.8% at the early harvests on September 20th and 30th, respectively. The corruption ratio was lowest on October 20th and October 10th at 29.3% and 39.1%, respectively. Conclusion : Ford. Dioscore alata cultivation, Korea presents a premature and disadvantageous environment with lower temperature and pre-harvest frost at the time of planting. After raising seeding on an electrically heated hot bed, the optimal harvesting stage should be from planting in the middle of April where temperature rises above 1 5℃ to harvesting in the period October 10th - 20th so as to achieve the maximum tuber yield and high storability.

Background : study of long yam and short yam (Dioscorea. opposita) are cultivated in temperate regions but tropical yam (Dioscorea alata) are mainly grown in Africa and sub-tropical regions cultivated crops. Recent tropical yam cultivation area of Korea increased but lack the proper cultivation techniques to climate warming. This study was conducted to elucidate the effect of the timely harvest on Tropical yam at 2015 in Institute of Bioresources Research, GBARES. Methods and Results : Tuber of tropical yam were cut as 40 g, and dust-coating sterilized with lime. Seedlings were grown in heating wire installed seed bed from 11. March to 16. May. Experimental field were fertilized 2,000 kg compost, 34 kg N2, 28 kg P2O5, and 28 kg K2O. All amount of compost and P2O5 treated as basal fertilizer. N2 and K2O treated 14 and 10 kg of basal fertilizer, and 20 and 18 kg of additional fertilizer, respectively. Tillage, covering black PE film with 60×25 cm spacing holes on 120 cm row were conducted. Emergence days from 6. April to 18 May until 28 days to 36 days but 15. June and 9. June were each 19 and 7 days. Dry weigh in early stage due to seedling date, while seedling date according from 6. April to 18. May had no difference. seedling date was not effective on total number of tuber but number of marketable tuber (over 200 g). Marketable tuber number of seedling date according to 20. April was increased 35~132% as 4,028 number per 10 a. And tuber with 20. April was 13~73 g heavier. Tuber yield and marketable tuber yield of seedling date as affected by 20. April were respectively 2,518 and 1,273 kg per 10 a compared to 6. April and from 4. May to 15. June as 1,743~2,457 kg and 484~1,027 kg. Conclusion : Tropical yam is low temperature in the cultivation of Korea but also adverse environmental conditions. Frost is not mature enough off before harvesting. Yam had significant increased marketable tuber (over 200 g) yield due to seedling in mid-April Requires cultivation technology.

Background : Yam absorbs nutrition and water through water absorptive root generated from head of rhizome. Round-shaped yam (RSY, Dioscorea opposita) and tropical round-shaped yam (TRSY, Dioscorea alata)are more sensitive to drought because of shorter head of rhizome and shallower root compared to long yam or short yam. This study was conducted to elucidate the effect of irrigation on RSY and TRSY yam at 205 in Institute of Bioresources Research, GBARES. Methods and Results : Tuber of RSY and TRSY were cut as 40 g, and dust-coating sterilized with lime. Seedlings were grown in heating wire installed seed bed from 25. March to 16. April. Experimental field were fertilized 2,000 kg compost, 34 kg N2, 28 kg P2O5, and 28 kg K2O. All amount of compost and P2O5 treated as basal fertilizer. N2 and K2O treated 14 and 10 kg of basal fertilizer, and 20 and 18 kg of additional fertilizer, respectively. Tillage, installation of drop-watering tapes, and covering black PE film with 60×25 cm spacing holes on 120 cm row were conducted. 20 L per m2 was irrigated 7 days interval except rainy day from middle of May to late of September. RSY had high emergence rate in early stage due to irrigation, while TRSY had no difference. Irrigation was not effective on total number of tuber but number of marketable tuber (over 200 g). Marketable tuber yield of RSY according to irrigation was increased 89% as 1,147 kg per 10 a. And tuber with irrigation was 73 g heavier. Tuber yield and marketable tuber yield of TRSY as affected by irrigation were respectively 2,611 and 1,715 kg per 10 a compared to control, 1,462 and 428 kg. And irrigated tuber was 66 g heavier. Conclusion : TRSY had more effective on irrigation than RSY. Both of yam had significant increased marketable tuber yield due to irrigation. Therefore RSY and TRSY are necessarily irrigated because of those absorptive characteristics, short head of tuber and shallow root.

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 ml liquid medium containing 10 g/L activated charcoal, 3x MS salts and 250 g/L sucrose was the most effective in micro-tuber growth.

둥근마 액체배양에서 소괴경의 생산을 위하여 배양온도와 일장의 전환과 배양 배지의 교체 효과를 조사하였다. 둥근마 액체배양에서 식물체의 증식을 위한 일장시간은 6주의 배양기간 동안 25℃에서 16시간보다는 24시간이 효과적이었다. 기내소괴경의 생산을 위하여 배양기간을 12주로 연장하여 배양하였으며, 배지교체의 효과를 검토하기 위하여, 배양 중기인 배양 후 6주째에 새로운 배지로 교체하였더니, 배지를 교체하지 않은 것보다 소괴경의 형성수가 평균 5개씩 더 많았고, 소괴경무게도 70% 이상 증가하였다. 배양환경의 전환이 소괴경 형성에 미치는 효과를 알아보기 위하여, 12주의 배양기간 중에 식물체 생장이 활발한 초기 6주간은 25℃에서 24시간의 일장환경에서 배양하고, 이후 6주간의 배양온도와 일장시간을 전환하였다. 배양온도는 25℃가 15℃보다 효과적이었고, 25℃에서 일장시간은 24시간이 암처리 또는 8시간 일장처리보다 효과가 있었다. 12주간의 배양기간중에 배지 교체의 적절한 시기는 배양 후 2, 4, 6, 8, 10주째 또는 배지 무교체 처리구중에서, 생체중, 마디수, 소괴경수에서는 2주 또는 6주째에 교체하는 것이 좋았고, 소괴경중은 8주째 교체 처리구에서 가장 무거웠으나 소괴경의 수와 무게를 모두 고려하였을 때, 초기 배양 후 6주째에 배지 교체하는 것이 가장 효율적이었다. 12주간의 배양기간 중 배양 후 6주째에 교체할 배지의 성분은 sucrose 30, 60 g·L-1 또는 sucrose 60 g + BA 0.1 mg·L-1 함유 배지 중에서 sucrose 60 g·L-1이 함유된 배지로 교체하였을 때, 소괴경의 총무게가 가장 무거워 소괴경의 비대에 가장 효과적이었다. 따라서, 둥근마의 액체배양시 25±1℃, 24시간 광조건으로, 마디접종 후 6주째에 sucrose 60 g·L-1를 함유한 배지로 교체하여 6주간 추가 배양하는 방법이 기내 식물체와 소괴경의 생장과 형성에 가장 효과적이었다.