• Journal of the Korean Society of Food Culture
• /
• v.25 no.6
• /
• pp.801-809
• /
• 2010

This study investigated the quality characteristics of Sulgidduk with different levels (0, 4, 8, 12, 16%) of added yam powder by measuring water content, color value, texture, and sensory quality. The water content of Sulgidduk decreased significantly (p<0.05) by increasing the amount of yam powder. The Hunter's L value of Sulgidduk decreased, and the a and b values increased significantly. Mechanical texture parameters, such as hardness, cohesiveness, gumminess, adhesiveness, and chewiness decreased significantly (p<0.05) as the amount of added yam powder increased. The springiness of the 0, 4, 8 and 12% yam Sulgidduk was not different significantly, but springiness decreased significantly in the 16% yam Sulgidduk. Hardness increased significantly during storage, whereas cohesiveness, gumminess, and adhesiveness decreased. Springiness of the control sample increased significantly, but the Sulgidduk with added yam powder had the highest springiness levels during the first and second days. Chewiness was highest during the first day in all Sulgidduk preparations. The 12% yam Sulgidduk was the best in color, flavor, taste, moistness, chewiness, and overall acceptability from the sensory evaluation. These results indicate that Sulgidduk with 12% added yam powder had the best quality in sensory and texture analyses.

• 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.

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

• Journal of the Korean Society of Food Culture
• /
• v.26 no.2
• /
• pp.184-189
• /
• 2011

In the present study, we investigated the physicochemical characteristics and sensory qualities of gruel with added ground yam (20~80%) to increase consumption and application of yams. pH and sugar content of sample gruel decreased with increasing yam content, whereas spreadability increased gradually. Lightness and greenness decreased; however, blueness increased as yam content increased. Viscosity decreased with increasing yam content. Gruel with 40% added yam was the most preferred for flavor, taste, texture, and overall preference. From these results, we found that adding 40% yam was the best to make gruel with high sensory quality.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.4
• /
• pp.805-809
• /
• 1999

The growth of Lactobacillus casei in milk was enhanced by adding yams. Addition of 1% yam(raw or dry) promoted the cell growth and acid production in fermented milk. The milk containing 1% yams formed the complete curd by lactic acid fermentation at 37oC for 19hr while the milk without yams showed the incomplete curd formation. The crude mucilage extracted from a raw yam also enhanced the cell growth as well as the acid production. Addition of mucilage(0.08%) showed the similar effects with adding heat treated yam(1%). The milk fermented by adding various yams showed the high scores for sensory evaluation comparing with the milk fermented without yams. The fermenting ability of Lactobacillus acidophilus, Lactobacillus kefir and Leuconostoc mesenteroides was evaluated by adding 1% of a dry yam in milk. A dry yam also enhanced the cell growth of L. acidophilus resulting in the high acid production. The viable cell counts of L. casei, L. acidophilus and Leuc. mesenteroides except L. kefir were increased by adding 1% of a dry yam.

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

• 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.

• 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 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.