• Korean journal of food and cookery science
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• v.23 no.6
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• pp.884-890
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• 2007

The purpose of this study was to investigate the effects of adding various concentration of yam powder (Y0:0g, Y1:2g, Y2:4g, Y3:6g, Y4:8g, Y5:10g) on the physicochemical and sensory characteristics of jelly. The pH of the samples ranged from 5.61 to 5.70, and this pH range was stable. As for the viscosity of the jelly, the samples made with yam powder showed higher viscosities than the control. and the viscosity increased with increasing amounts of yam powder, viscosity was increased. The Hunter color L- and a-values decreased significantly (p<.001) by the addition of yam powder. For the textural characteristics, the addition of yam powder increased the cohesiveness and decreased the springiness and chewiness. In the sensory evaluation, the appearance and flavor acceptability of the jellies were in the order of Y0>Y1>Y2>Y3>Y4>Y5. The texture acceptability was highest in Y0 and Y1 and taste and overall acceptability were highest in Y1.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.444-447
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• 2006

Yam powders were prepared by freeze, fan, hot-air, and coal-heat drying. The viscosities of their suspensions and supernatants and the viscosity changes with addition of sugar, salt, and citric acid were investigated. Viscosity (43 mPa s) of 7.5% suspension of fan-dried yam powder was lower than that of freeze dried yam (58.1 mPa s), but much higher than that of the conventional, hot-air dried yam (17.2 mP s). Coal-heat dried yam had a viscosity of only 4.5 mPa s. The viscosity was related to the protein denaturation induced by heat and acid. Addition of sugar to yam powder increased the viscosity of the suspension but no changes were evident with salt addition. Viscosities decreased when 0.5% citric acid was added (pH 3.4-3.5).

• The Korean Journal of Ceramics
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• v.1 no.1
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• pp.35-39
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• 1995

Yttrium aluminum garnet(YAG) powders were synthesized by spray-drying of the hydroxides coprecipitated from a mixture of aqueous solutions of $Al(NO_3)_3.9H_2O \;and\; Y(NO_3)_3.6H_2O$ Phase formation in the powders during heat treatments and their sintering charactristics were investigated. In the powder obtained by washing the hydroxides before spray-drying, a metastable yttrium aluminum hexagonal (YAH) phase was first crystallized and then transformed into YAG as temperature was increased. The formation of YAH was attributed to a deviation in compositions of the particles from the starting composition of YAG. However, the powder prepared without washing step contained a stable yttrium aluminum monoclinic(YAM) phase in addition to YAG due to a large deviation from the starting composition. A powder compact of a single phase YAG was pressureless-sintered for 4 hrs at $1700^{\circ}C$ and the density was 93% of the theoretical density.

• Culinary science and hospitality research
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• v.20 no.6
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• pp.56-68
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• 2014

Yam Yackwa (YP) was made by addition of yam power (15%) into flour. Depending on extension of storage time, lightness and redness of YP were increased. Yellowness of YP was decreasing until 3 days and increased from 9 days of storage. However, the yellowness of Yackwa without Yam powder (Non-YP) was increasing until 3 days and decreased from 6 days of storage. Hardness, gumminess, and chewiness of YP were improved compared to Non-YP. It means that the addition of yam power makes Yackwa soft. Oil absorption of Non-YP was low. Acid value and peroxide value of YP were 1.57 and 19.04, respectively. Moisture contents, crude ash, crude fat, crude protein, and carbohydrate of YP were $2.55{\pm}0.08%$, $0.71{\pm}0.01%$, $6.11{\pm}0.06%$, $15.97{\pm}1.40%$, and $64.66{\pm}0.09%$, respectively.

• Journal of Nutrition and Health
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• v.32 no.6
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• pp.637-643
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• 1999

The effects of yam(Dioscorea) on lowering cholesterol level and its mechanism were investigated. The concentrations of plasma and liver lipids, and the excretions of fecal neutral sterol and bile acid were measured in male Sprague-Dawley rats. Five Groups of 8 rats were fed hypercholesterolemic diet(1% cholesterol, 10% lard ; control), hypercholesterolemic diet plus 15% or 30% dried yam powder prepared by either hot-air(15HY, 30HY) or freeze dry(15FY, 30FY) for 4wk. Plasma total lipid, total cholesterol and cholesterol level was also significantly lower(28%, p<0.05), buy HMG-CoA reductase activity was higher in 30FY(230%, p<0.05) than in control. Although no significant differences in fecal neutral sterols were observed among groups, the yam-fed rats apparently had less bacterial degradation of cholesterol as indicated by a significantly greater of fecal cholesterol to coprostanol than in controls. Total fecal bile acids were significantly greater in rats fed yam(15HY : 5 folds, 15FY ; 12,30HY ; 12, 20FY ; 22) than in controls. The ratio of secondary to primary bile acids was almost 8 times lower in 30FY than in control. These data indicate that yam lowers cholesterol both in plasma and in liver through increasing fecal bile acid excretion as well as HMG-CoA reductase activity. Freeze-dried yam, which possesses viscosity, was more effective in cholesterol-lowering action than hot-air dried one.

• Preventive Nutrition and Food Science
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• v.4 no.3
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• pp.193-196
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• 1999

To investigate the effect of yam on the activity of benzo[a]pyrene hydroxylase(BPH), the key enzyme associated with polycyclic aromatic hydrocarbons(PAHs) metabolism, rats were fed a fiber free diet for 7 days, whereupon they were switched to experimental diets for another 7 days. Diets contained benzo[a] pyrene(BP, 400 mg/kg diet) and 25% or 50% yam powder (freezer dried and hot air dried ). Diets containing pectin and cellulose were compared with diets containing yam. BPH activities were assessed in the liver, lung, kidney, stomach, small intestine and large intestine of rats. BP induced BPH activities in various tissues ; 8 fold in liver, 28 in lung and stomach , and 32 in large intestine. The addition of yam significantly lowered BPH activity in liver, lung and stomach and hot air dried yam was nmor eeffectivie than freeze dried yams. These data suggested that yam containing diet may influence carcinogen metabolism in liver and extrahepatic target tissues by altering activities of BPH and may reduce exposure of these tissues to dietary carcinogens.

• Food Science and Preservation
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• v.15 no.1
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• pp.49-57
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• 2008

This study was conducted to develop an optimal composite recipe for a cookie including yam powder that would be attractive to all age groups. Wheat flour was partially substituted by yam powder to reduce the content of wheat flour. This study has produced the sensory optimal composite recipe by making cookies, respectively with each 5 level of yam powder $(X_1)$, Sugar$(X_2)$, butter$(X_3)$, by C.C.D (Central Composite Design) and conducting sensory evaluation and instrumental analysis by means of RSM (Response Surface Methodology). Sensory items showed very significant values in color, softness, overall quality (p<0.01), flavor (p<0.05) and those of instrumental analysis showed significant values in lightness, redness (p<0.05), spread ratio, hardness (p<0.01). Also sensory optimal ratio of yam cookie was calculated at yam powder 37.35 g, sugar 50.75 g, butter 78.40 g and it was revealed that the factors of influencing yam cookie aptitude were in older of yam powder, butter, sugar.

• 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.

• Food Science and Preservation
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• v.16 no.5
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• pp.680-685
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• 2009

We assessed the quality characteristics of instant Nuroong-gi prepared with 0%, 2%, 4%, 6%, or 8% (all w/w) yam powder. We measured color, water binding capacity, viscosity, the sedimented volume of insoluble solids, turbidity, total sugar, and reducing sugar and conducted sensory evaluation. Lightness decreased with a rise in the proportion of yam powder. However, both redness and yellowness rose with an increasing proportion of powder. The water binding capacities of Nuroong-gi prepared with yam powder were higher than that of rice powder. The viscosity increased with increasing levels of powder. The level of insoluble solids, the turbidity, and the concentrations of total sugar and reducing sugar all rose with increasing cooking temperature. Sensory evaluation showed that Nuroong-gi with yam powder at 2% (w/w) was optimally acceptable.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.877-882
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• 1998

To establish optimum drying methods for Korean yam, freeze drying, cool air drying and hot air drying methods were compared by determining some quality criteria. The native color, odor, taste and viscosity of raw yam were preserved by only freeze drying at less than $40^{\circ}C$. The native white color of yam changed to brown and odor and taste of yam decreased largely by cool air drying and hot air drying. Especially cooked and roasted flavor was developed in hot air dried yam. The viscosity of cool and hot air dried yam was about half than that of freeze dried yam. Conclusively freeze drying method was shown optimum to preserve quality properties of yam such as viscosity, color, odor and taste. The physical properties of yam powder such as dispersiveness and solubility was the best in $40{\sim}60{\;}mesh$ particle size.