• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.1
• /
• pp.56-63
• /
• 2001

This study investigated the quality characteristics of yeast breads with addition of hot air-dried yam powder (HDYP) and freeze-dried yam powder (FDYP), using several physical and sensory examinations. Breads were made of imported wheat flour (IWF) or Korean wheat flour (KWF). HDPY and FDYP were added to the bread formula at three levels of 3, 5, and 7%. The addition of yam powders required an increase of water absorption. As the addition of HDYP/FDYP increased, IWF dough stickiness increased and thus handling property became inferior to the control. Especially, handling property of KWF bread dough containing FDYP was most poor among the dough samples. With HDYP/FDYP, final volumes of bread made from IWF were similar to the control when 3~5% HDYPs were added whereas loaf volumes decreased significantly as the amount of added FDYP increased, indicating volume depressing effect. In bread scoring, texture scores increased when yam powders were added that hardness, chewiness, cohesiveness and guminess of KWF bread increased as the amounts of yam powders increased. The "L" value of IWF bread crumb decreased with the addition of yam powders. From sensory evaluation using acceptability scores, the results gave us that appearance, grain, texture, flavor, taste and overall acceptability of KWF bread could be more improved with the addition of yam powders than those of IWF bread.IWF bread.

• Fibers and Polymers
• /
• v.7 no.4
• /
• pp.420-423
• /
• 2006

Spandex has been successfully applied on modified worsted spinning system to produce spandex core spun yam. However it's difficult to produce wool/spandex core-spun yam on woolen spinning system with the same modified device because the drafting device of the two systems is quite different. A new method is introduced to apply spandex on woolen spinning system in this paper. Core-spun yam produced in this way has good appearance and quality by comparing with normal yam. A series of experiments were carried out to study the influence of spandex drafting ratio and yam twist factor on tensile' properties and elasticity of core-spun yams. The results indicate that core-spun yam with spandex drawing ratio of 2.5 and twist factor of 13.63 has highest value of tenacity and breaking elongation.

• Culinary science and hospitality research
• /
• v.14 no.4
• /
• pp.441-455
• /
• 2008

The primary objective of this research was to investigate the recognition, preference and the present using status of yam for the data which will be useful to make consumers intake more yams and to develop more yam processed products. Almost all respondents who had eaten yams liked it, and Andong people eat more yams than Daegu people. About 60.3% respondents who like yams cited the reason was "it's good for health". Among the respondents who had eaten yams recognized it as nutritional, healthful, and diet food compared with the respondents who had not eaten yams. Recognition degree was higher when the preference for yams was higher. Among the types of yam processed cooking, according to intake ratio, yam juice formed 38%, followed by bleaching(17%) etc. Among the types of yam processed food, powdered tea formed 34%, followed by yam gruel(24%), yam drinks(19%) etc. It showed that respondents eat very few foods made from yams and yam processed food. As for purchasing yam processed food, the result showed that the main concerns of the respondents were the "ratio of yams"(24.9%), followed by "tastes"(21.3%) etc. The largest group (29.4%) of the respondents suggested that the improvements of yams were "diversification of the processed food" followed by "improved taste"(26.4%) while 62.5% of the respondents indicated that they would buy yams after its improvement, which showed a good prospect of yam processed food.

• Korean Journal of Plant Resources
• /
• v.18 no.1
• /
• pp.161-168
• /
• 2005

Tuber yield and content of general component and diosgenin which is a main bioactive property were investigated in order to determine the growth characteristics of round typed yam(Dioscorea opposita L.) and the potential of artificial culture at Suwon, Korea. Tubers of round yam were initiated to form at 60 days after planting and then enlargement of tubers lasted by 160 days after planting. Compared to short typed yam(108g), tuber weight of round yam was higher(127g) on the basis of dry weight at 200 days after planting. In comparison of general component between round yam and short yam, protein of round yam$(3.62\%)$ was higher than short yam$(2.10\%)$. Water content in round yam$(64.5\%)$ was lower in short yam$(79.4\%)$, indicating a higher dry weight ratio of round yam. Hardness of round yam was 2787.6 while short yam showed about two times higher hardness(4946.9). Lightness was higher in round yam(77.4). In tuber extracts analysis, diosgenin content was respectively $3.32\%$ in round yam and $2.61\%$ in short yam.

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

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.5
• /
• pp.908-913
• /
• 1998

Chemical components and some physical proeprties of fresh, defrosted and dried yams(Dioscoreab batatas) were determined to obtain basic data for high quality yam processing. Fresh yam showed 81.79% moisture and 15.24% N-free extract. The cohesiveness and adhesiveness of defrosted yam homogenate were significantly higher than those of fresh yam homogenate. Free sugars of yam were mainly composed of sucrose, rhamnose, fructose and glucose, and the contents of fructose and glucose were apparently decreased by hot air drying. Linoleic(45.64%), oleic(8.32%), and arachidic acids(7.40%) were major fatty acids of yam. Hot air drying caused a decrease in unsaturated fatty acids and an increase in saturated acids. Hot air-dried yam powder showed higher gelatinization properties than freeze-dryed yam powder, such asinitial pasting temperature, temperature at maximum viscosity, and viscosity at different parameters. Hot air-dried yam powder showed higher Hunter parameter b and ΔE values and lower L value than freeze-dried one.

• Journal of Korean society of Dental Hygiene
• /
• v.7 no.1
• /
• pp.53-59
• /
• 2007

Yam was stepwise extracted with hexane, chloroform, ethyl acetate, butanol, and water. Antibacterial activity of each extract was investigated. 1. Methanol extract of Yam was examed against to antibacterial effects on S. mutans KCTC 5316, P. gingivalis KCTC 5352, S. aureus KCTC 1927 by means of agar diffusion method. 2. The methanol extract of Yam was showed very powerfull antibacterial activity on S. mutans, but not showed on P. gingivalis, and S. aureus. 3. The MIC of Yam hexane fraction was 0.25 mg/ml for S. mutans KCTC 5316. 4. The Yam hexane fraction strong inhibited the growth of S. mutans, in the culture medium at concentration of 0.25 mg/ml.

• Microbiology and Biotechnology Letters
• /
• v.35 no.2
• /
• pp.135-141
• /
• 2007

To increase the consumer acceptability of yam and the shelf-life of fresh-cut yam, organic acid-treated fresh-cut yam was prepared. When uncontaminated fresh-cut yam was stored at $4^{\circ}C$ for 14 days after treatment with 1% (v/w) organic acids, the browning and microbial putrefaction of fresh-cut yam were inhibited by treatment of acetic acid or maleic acid, whereas treatment of citric acid and ascorbic acid, commonly used browning inhibitors in food industry, did not show apparent effects on the browning and putrefaction of yam. The Inhibitory effects of acetic acid or maleic acid were superior than those of NaOCl (100 ppm), hydrogen peroxide (100 ppm) or commercially available washing solution. Also, treatments of 1% acetic acid, or 1% maleic acid Into artificially-contaminated yam $(10^5\;CFU/g-yam)$ showed strong inhibition of browning and putrefaction during long term storage at $4^{\circ}C$. The growth inhibition test indicated that 0.1% is enough to inhibit the growth of psychrotrophic yam-putrefactive Pseudomonas sp., and treatment of 0.1% acetic acid, or 0.1% maleic acid inhibited the browning and microbial putrefaction of fresh-cut yam. Our results suggested long-term distribution of yam or other root crops products is possible by treatment of organic acid, such as acetic acid, combined with aseptic vacuum packaging technology.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.1
• /
• pp.48-55
• /
• 2001

This study investigated the quality characteristics of sponge cakes with addition of yam (Dioscorea) powders prepared by different drying methods, hot air (HDYP : hot air dried yam powder) and freeze drying (FDYP: freeze dried yam powder), using several physical and sensory examinations. For the foam forming ability and foam stability, the specific gravities of egg foams containing 5% yam powders were measured by drainage using funnels for 78 hrs. The results showed that HDYP and FDYP did not affect the foam forming ability but FDYP increased foam stability due to increased viscosity. When the strength of 8% gels composed of wheat starch and HDYP/FDYP was measured to predict the setting of cake structure, the strengths of starch gels containing yam powders were higher than those of control without yam powders. The volume of sponge cake containing 5% HDYP increased whereas those containing FDYP decreased at the levels of 5, 7%. From the texture profile analysis data, hardness, gumminess and chewiness of cakes containing yam powders increased. The color of cake crust and crumb became darker as the amount of yam powders increased. The results of sensory evaluation by QDA (quantitative descriptive analysis) to compare two different drying methods showed that appearance and texture of cakes containing 5% HDYP were closer to those of control than cakes containing 5% FDYP but overall acceptability of sponge cakes containing yams were comparable to the control cakes regardless of drying methods. The addition of yam powders to sponge cakes increased yam flavor and decreased egg smell. Therefore, it can be suggested that HDYP and FDYP can be added to the sponge cake formula up to 7% and 5%, respectively.

• Textile Coloration and Finishing
• /
• v.13 no.5
• /
• pp.346-352
• /
• 2001

This study surveys the fiber behavior in yam formation and the physical properties of Solo-spun yam. The specimens were made by six types of Solo-spun rollers with fixed twist multiplier. The physical properties such as yam count, evenness, strength, and breaking elongation of these yams were compared with the properties of ring spun yams and analysed with the mechanism of Solo-spun yarn formation. The grooves on the surface of Solo-spun roller divide the web and interfere the twist propagation. These phenomena cause the uneven draft and the fly of fiber, so the Solo-spun yam becomes finer than fing-spun yam and the yam breaking strength and elongation deteriorate, but these demerits can be improved with rounding the protruded edge of Solo-spun roller grooves.