• Journal of the East Asian Society of Dietary Life
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• v.22 no.2
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• pp.231-238
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• 2012

$Dioscorea$ $batatas$ Decne is a type of yam that eaten raw and used as a traditional oriental medicine in Asian countries. In this study, we evaluated the functional effects of yam water extracts on body weight levels and serum lipid concentrations in mice fed high fat diet. Mice were divided into four groups: normal diet control (ND), high fat diet control (HFD), HFD+yam extract 100 mg/kg (HFD-Y100), and HFD+yam extract 200 mg/kg (HFD-Y200). Yam extract was administrated orally to mice fed a high fat diet for 5 weeks. Treatment with yam extract significantly reduced body weight levels and energy efficiency in a dose-dependent manner in HFD-fed mice. Yam extract also attenuated serum levels of triglyceride, total cholesterol, and LDL-cholesterol, as well as organ weights of liver and abdominal adipose tissue in mice fed a high fat diet. Moreover, blood levels of glucose, insulin, and leptin significantly decreased in a dose-dependent manner upon administration of yam extract. Blood activities of GPT, GOT, and LDH were lower in the yam extract-treated groups compared to the HFD group. These results indicate that yam water extract may reduce elevated body weight and serum lipid concentrations in mice fed a high fat diet, suggesting its usefulness as a functional food for reducing body fat and hyperlipidemia.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.153-160
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• 2011

In this study, we have developed taste and other functional enhancements of yam chips, from tasteless and flavorless yam slices, through the process of soaking freeze-dried yam in different commercially available juices, including apple, omija (fruit of Maximowiczia typica), grape, wild grape, orange, tomato, red ginseng, and black garlic juice. The analyses of color (brightness, redness and yellowness), pH, brix, acidity, total polyphenol, total flavonoids, total sugar and reducing sugar, DPPH and ABTS scavenging activity, reducing power and nitrite scavenging activity, of the different yam chips showed that the freeze-dried yam slices absorb various components of fruit juices, such as flavonoids, sugars, organic acids and flavors, during the soaking process. These changes resulted in increased taste (both sweet and sour tastes), flavor and antioxidant activity in the yam chips. The soaking time for yam slices in juice is considered to be a crucial factor for the taste and bioactivity of yam chips. In the case of grape juice-yam chips, which had the highest preference among the 8 different chips, the optimum soaking time was noted as 120 seconds. The optimization of the soaking process is necessary for various juices. These results suggest that taste, and other functional enhancements, in yam chips can be developed by juice-soaking and freeze-drying methods.

• The Korean Journal of Community Living Science
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• v.23 no.1
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• pp.31-39
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• 2012

Yam($Dioscorea$ $japonica$) has been used in oriental medicine to modulate physiology, and it is considered as a potential functional food. So far, however, limited efforts has been performed to use yam for food processing and development. Thus, in this study, rice cakes called 'Backsulgi' containing 3%, 6% and 9% yam powder were prepared and the quality characteristics were evaluated. The results of this study showed that adding yam powder reduced the moisture content of Backsulgi, which led to a decrease in the strength of textural characteristics such as hardness, adhesiveness, cohesiveness, gumminess, chewiness, and springiness. In contrast, the quality characteristics of the sample containing 3% yam powder were not significantly different from those of the control in moisture content, texture, and overall acceptability. Consequently, adding 3% yam powder could improve the biofunctionality and quality characteristics of Backsulgi in the case of adjusting moisture content.

• Nutrition Research and Practice
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• v.1 no.2
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• pp.94-99
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• 2007

The immunostimulating activities of mucilage fraction from yam were investigated. The proliferation of BSA-primed lymph node cells was enhanced between 4.1- to 10.9-fold compare to control, when cultured with 1 to $25{\mu}g/mL$ of yam-mucilage fraction. It showed strong immunostimulating activity than ginseng extract and as remarkable as Bifidobacterium adolescentis M101-4 known as a positive immunostimulator. Mitogenicity to lymph node cells was fully induced by concanavalin A and lipopolysaccharide. The proliferation of splenocytes and Peyer's patch cells was enhanced between 5.0- to 14.1-fold and 2.4- to 6.4-fold, respectively, when cultured with 1 to $25{\mu}g/mL$ of yam-mucilage fraction. It enhanced the production of cytokines such as tumor necrosis $factor-{\alpha}$ and IL-6 in the culture of RAW 264.7 macrophage cells. In the culture of lipopolysaccharide-stimulated RAW 264.7 cells, production of cytokines was as similar as compared to controls. In unstimulated RAW 264.7 cells, both tumor necrosis $factor-{\alpha}$ and IL-6 production were enhanced between 15.6- to 60.1-fold and 2.3- to 9.1-fold, respectively. Mucilage fraction from yam is expected to be a safe immunopotentiator to maintain the host immunity and develop a physiologically functional food.

• Food Science of Animal Resources
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• v.31 no.1
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• pp.66-73
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• 2011

Physicochemical and sensory properties of Dioscorea opposita Thunb. (yam) powder-added yogurts (1, 3, 5, and 7%, w/v) were examined when stored at $4^{\circ}C$ for 16 d. When the yam concentration increased, the pH increased with 16 d storage. The lactic acid bacteria counts in all yogurt samples showed an increase during storage period, and the highest counts were appeared with 7% yam powder addition. The dramatic decrease was found in viscosity with higher concentrations of yam powder-added yogurt samples. No change was found in allantoin and diosgenin contents for 16 d storage periods. A significantly strong bitterness and astringency and decreased viscosity were found with 5 and 7% yam powder addition. However, less than 3% yam powder-added yogurt samples did not show a significant difference compared with the control (p>0.05) and overall acceptability score was the highest in 3% yam powder-added yogurt throughout the storage. The present study indicated that the concentrations (1 and 3%, w/v) of yam powder could be used to produce yam powder-added yogurt without significant adverse effects on physicochemical, microbial and sensory properties, and enhance functional components from the supplementation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.751-755
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• 1998

Functional properties of yam mucilage were investigated by physicochemical analysis. Yam mucilage was extracted from the root of yam and then separated into two fractions by its selective aggregation with isopropanol concentration. Each mucilge fraction showed the excellent binding properties with heavy metal ions Co, Cr and Cu. Cr showed the higher affinity with mucilage than Co and Cu at pH 6.3. In ACE inhibition, IC50 values of mucilage fraction 1 and 2 showed 8.99$\mu\textrm{g}$/${mu}ell$ and 7.1$\mu\textrm{g}$/${mu}ell$, respectively.

• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.66-72
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• 2007

Yam has been recognized as healthy food due to its various biological activities, such as anti-obesity, antimicrobial, anticancer and immune-stimulation activities. In this study, antibacterial activities of 800 more natural plant extracts against yam-putrefactive psychrotrophic bacterium, Pseudomonas rhodesiae YAM-12, were evaluated to select a natural preservative, which is useful to long-term storage of yam and fresh-cut production. Finally, the clove oil was selected, and applied for the production of yam fresh-cut. The 1% of clove oil treated fresh-cut showed minor color changes during 31 days storage at $4^{\circ}C$ and the microbial growth was not detected. When the artificially contaminated fresh cut by dipping with P. rhodesiae YAM-12 suspension for 3 min was treated 1% clove oil, the microbial growth was identified to $10^4$ CFU/g from $10^3$ CFU/g with minor color changes. Whereas, treatment of sterilized water, or 100 ppm NaOCl into artificially contaminated fresh cut showed severe putrefaction $(10^8\;CFU/g)$ and color changes. Considering the previous reports that clove oil has antimicrobial, antioxidation, and antithrombosis activity, the use of clove oil into the yam fresh cut will provide market safety and consumer acceptability by prevention of microbial putrefaction and its biological activity.

• The Korean Journal of Food And Nutrition
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• v.35 no.4
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• pp.268-275
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• 2022

The purpose of this study was to confirm the possibility of using Korean purple yam (Dioscorea alata) as proximate composition, material, and antioxidant activity. In the proximate composition of the freeze-dried purple yam powder, the carbohydrate content was the highest at 86.67%, and in minerals, potassium showed the highest content at 1,765.69 mg/100 g. To study the antioxidant activity of purple yam, distilled water and 70% ethanol were used as extraction solvents. The total polyphenol, total flavonoid, and total anthocyanin contents were 1.3~1.6 times higher in 70% ethanol extract, than in the distilled water extract. As a result of ORAC, DPPH and ABTS radical scavenging activity, SOD activity, and reducing power, the 70% ethanol extract showed higher antioxidant activity than the distilled water extract in all results. As a result of freeze-drying purple yam and measuring antioxidant activity by extraction solvents, it is concluded that purple yam can contribute to the food industry as a natural antioxidant and health functional material.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.194-203
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• 2014

Yam (Dioscorea batatas) is widely consumed as functional food for health promotion mainly in East Asia countries. We assessed whether yam root (tuber) or bark (peel) extracts stimulated the activity of osteoblasts for osteogenesis. MC3T3-E1 cells (mouse osteoblasts) were treated with yam root extracts (water or methanol) (study I) or bark extracts (water or hexane) (study II) within $0{\sim}10{\mu}g/mL$ during the periods of osteoblast proliferation (5~10 day), matrix maturation (11~15 day) and mineralization (16~20 day) as appropriate. In study I, both yam root water and methanol extracts increased cell proliferation as concentration-dependent manner. Cellular collagen synthesis and alkaline phosphatase (ALP) activity, both the indicators of bone matrix protein and inorganic phosphate production for calcification respectively, were also increased by yam root water and methanol extract. Osteoblast calcification as cell matrix Ca and P accumulation was also increased by the addition of yam root extracts. In study II, yam bark extracts (water and hexane) increased osteoblast proliferation and differentiation, as collagen synthesis and ALP activity and osteoblast matrix Ca and P deposition. The study results suggested that both yam root and bark extracts stimulate osteogenic function in osteoblasts by stimulating bone matrix maturation by increasing collagen synthesis, ALP activity, and matrix mineralization.

• Research in Plant Disease
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• v.23 no.1
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• pp.82-87
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• 2017

During 2012 to 2014, a survey for the presence of viral diseases in yam plants was carried out in a field of the Institute for Bioresources Research in Gyeongsangbuk-do, Korea. A total of 88 leaf samples were collected and tested by reverse transcription polymerase chain reaction using specific primer sets. Eighty-one samples were positive for Broad bean wilt virus 2 (BBWV2), Chinese yam necrotic mosaic virus (ChYNMV), Cucumber mosaic virus (CMV), Japanese yam mosaic virus (JYMV), and Yam mild mosaic virus (YMMV), whereas Yam mosaic virus (YMV) was not detected. Additionally, seven samples were negative for all viruses. Several samples exhibited mixed (double and triple) infections. Three viruses (CMV, JYMV, and YMMV) were detected for the first time in yam plants in Korea. A BLAST search showed that three viruses shared nucleotide identities with CMV-Ca (98%), JYMV-O2 (91%), and YMMV-TG_NH_1 (86%). Thus, our findings confirmed that yam plants cultivated in Korea were infected with multiple viruses with three of these viruses reported for the first time in Korea.