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

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

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

• Journal of the East Asian Society of Dietary Life
• /
• v.27 no.3
• /
• pp.304-312
• /
• 2017

This study was carried out to evaluate the effects of yam powder addition (0~40%) on the quality characteristics and oxidative stability of yackwa made with rice flour. While most rice flour (34.35%) had a particle size more than $250{\mu}m$, 75% of yam powder had a particle size less than $65{\mu}m$. Width, height, and volume of rice yackwa added with yam powder increased with increasing yam powder content. While L and b values of rice yackwa added with yam powder decreased with increasing yam powder content, a value increased. Hardness and chewiness of rice yackwa added with yam powder increased as storage period increased at $25^{\circ}C$ for 9 days, whereas they decreased with increasing yam powder content. In a discrimination test, brown color, flavor, sweetness, and bitterness increased with increasing yam powder content, whereas hardness decreased. In a preference test, taste, texture, and overall acceptance increased with increasing yam powder content. The acid and thiobarbituric acid (TBA) values of rice yackwa added with yam powder increased as storage period increased. However, acid and TBA values of the treated groups decreased with increasing yam powder content compared to the control group. Although 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activities decreased with increasing storage period, values increased with increasing yam powder content. It was found that yackwa quality, preference, and oxidative stability increased during storage with increasing yam powder content. From these results, addition of 40% yam powder would be the optimal conditions for making rice yackwa.

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

• Food Science of Animal Resources
• /
• v.31 no.1
• /
• pp.66-73
• /
• 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
• /
• v.6 no.1
• /
• pp.66-71
• /
• 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.

• 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.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.6 no.1
• /
• pp.50-62
• /
• 2004

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 was 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.

• 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.