The purpose of this study was to investigate the possibility of using air potato (Dioscorea bulbifera) powder to make sponge cakes. The sponge cake batter was made by adding 0, 10, 20, 30, and 40% of air potato powder, and the resultant anti-oxidative properties and quality characteristics were analyzed. The study showed that the height, batter yield, and loss rate of sponge cakes decreased as increasing amounts of air potato powder were added, but the weight, viscosity, moisture content, and specific gravity increased. An evaluation of the color showed that the L and b values were highest in the control group but the a value was highest in the 40% group. There was no significant difference between samples in terms of cohesiveness, although the study showed a significant increase in the hardness, chewiness, and gumminess as the quantity of air potato powder in the sponge cakes increased. The total polyphenol content and DPPH radical scavenging activity increased noticeably as more air potato powder was added to the sponge cakes. The results thus showed that the study groups with the addition of air potato powder showed higher antioxidant activity than the control group.

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.

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.

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.