• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.74-81
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• 1995

In the proximate composition of the yams of home product, wild yam was most abundant in crude lipid and crude protein, and those content in the cultivated yams, cultivated long yam and cultivated short yam were similar. Cultivated long yam is the richest in crude ash. African yam had more crude lipid and crude protein compare to those of home product yams. Especially, the amount of crude lipid in African yam was four-fold of home product yams. In the mineral content, Ca was the richest mineral in four kinds of yam. The rest of mineral were in order of Fe, Mn and Zn. Among the home product yams, the Ca content of wild yam was higher than that of cultivated yam. The contents of Fe, Mn and Zn were also high in wild yam compared to cultivated yam. In the composition of free sugars, the sucrose content is the highest in wild yam, cultivated short yam and African yam. in order The fructose content was the most abundant in cultivated long yam and the next was sucrose. The composition of free fatty acids were in order of lactobacillic acid, palmitic acid and palmitoleic acid. Crude saponin contents of the home products were almost similar levle, but crude saponin of wild yam was more abundant than that of cultivated yam. And crude saponin of African yam was much more abundant compared that of other home product yams. there is not much difference in the kinds of saponin from the home product yams. However, the amount of each saponin from the home product yams was different. In case of African yam, 'b' saponin did not appear and 'e' saponin was higher compared with home product yams. In African yam, the bitter taste from ethyl acetate layer was the strongest, and the next was n-butanol layer. It is possible that there was a powerful UV absorption material in the bitter taste of ethyl acetate layer and also supposed that there were saponin and phenol is material.

• Journal of the Korean Society of Food Culture
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• v.25 no.3
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• pp.342-349
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• 2010

This study evaluated the quality and sensory characteristics of sulgidduk added with yam powder (5~20%) during 4 days storage. The moisture content of samples initially decreased as the yam powder content increased, but subsequently increased during storage. The pH values also increased during storage, although there was no significant difference. L values decreased and both a and b values increased as yam powder content increased. The decreased L values during storage were not significantly different from control group. The hardness of samples decreased with increasing yam powder content, while hardness of control group markedly increased during storage. Cohesiveness increased as yam powder content increased, and tended to decrease during the storage. Springiness also initially increased as yam powder content increased. No change was apparent during storage in control group or samples added with up to 10% yam powder, while springiness was decreased insignificantly in samples with over 10% yam powder. Lightness, yam odor and savory taste of sulgidduk tended to increase as yam powder content increased, while chewiness decreased. The savory odor was the highest in sulgidduk added with 10% yam powder. Sulgidduk added with 10% yam powder was the most preferred in appearance, taste, texture and overall preference.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.753-761
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• 1990

The physicochemical properties of starches from aerial and subterranean tuber of yam were compared with those of rice and sweet potato. Aerial tuber yam contained higher level of amylose than others, whereas water binding capacity, swelling power and solubility was highest in subterranean tuber yam starch. Brabender amylograms of 5% starch suspensions indicated that the initial pasting temperature of yam starches were slightly higher than that of rice and sweet potato starches, the maximum viscosities of starches from subterranean and aerial tuber yam were 860 and 590 B.U., respectively. Yam starches were more difficult to hydrolyze by ${\alpha}-amylase$ than rice and sweet potato starches. ${\beta}-Amylolysis\;limit$ for yam starches and their amylose and amylopectin were higher than rice and sweet potato starches. The elution profiles of starches on Sepharose CL-2B were different from each other but they were similar between yam starches. Incomplete debranched fractions in the aerial tuber yam amylopectin was particularly higher than other samples. The weight ratio of short chains to long chains for debranched amylopectins was the lowest in aerial tuber yam.

• 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.

• Fibers and Polymers
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• v.6 no.1
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• pp.66-71
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• 2005

The surface evenness and texture are closely related with the irregularity of yam thickness. Besides, yam thickness variation has an important role to influence the yam performance and the textile process efficiency. Thus, the information not only on the yam thickness, but also on the short- term irregular characteristics that have not been known before is required for enhancing the qualities of textile products. This paper reports the results of a study about the yam thickness and its variation for various types of yam on the basis of a new measurement system applying a laser slit beam as a light source. The new method delivers effective information on the irregularity. The analysis of the measured signal confirms that the visual shade created by the yam doubling and twisting can be measured and the yam thickness characteristics can be represented by corre­lograms. Depending on yam types, correlograms have different shapes and can be approximated to an exponentially decaying function with or without fluctuating magnitude. In addition, the effective information on the yam irregularity can be influ­enced by the sampling length interval of the measuring device used for tests.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.109-114
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• 2006

Yam has been recognized as healthy food due to its various biological activities, such as anti-obesity, antimicrobial, anticancer and immuno-stimulation activities, and its consumption has been increased during last decades. In this study, to investigate low-temperature, long-term storage of yam and to develop processed yam products, yam-putrefactive psychrotrophic bacteria were isolated from rotted yam and identified based on BBL identification system, fatty acid analysis in cell membrane and 16S rDNA sequence analysis. The putrefaction activity of isolated thirteen bacteria was evaluated using yam-slices (NaOCl-treated, autoclaved yam and without treatment), and YAM-10 and YAM-12 were identified as major psychrotrophic putrefactive bacteria. Both YAM-10 (Pseudomonas cepacia) and YAM-12 (Pseudomonas rhodesiae) bacteria grew well at 4$\sim$12$^{\circ}C$ and showed strong activity of polymer degrading enzymes, especially amylase, carboxy methyl cellulase and xylanase, at 20$^{\circ}C$. But they failed to grow at acidic pH (<5) or alkaline pH (>10). Our results suggested that the control of psychrotrophic Pseudomonas sp. by pH change and inhibition of polymer degrading enzymes, such as amy-lase, are necessary to long-term storage of yam.

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

• 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.

• Journal of the Korean Society of Food Culture
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• v.26 no.2
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• pp.184-189
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• 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
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• v.28 no.4
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• pp.805-809
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• 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.