• Korean journal of food and cookery science
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• v.26 no.5
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• pp.545-551
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• 2010

In this study, Sulgidduk samples were prepared with 0%, 3%, 5% and 7% yacon powder. Sulgidduk samples were then examined for quality characteristics such as moisture content, general components, color, texture profile analysis, sensory qualities, and sugar content, in order to determine the optimal ratio of yacon powder in the formulation. Regarding the general components of yacon Sulgidduk, the contents of crude protein and lipid decreased as the ratio of yacon powder increased. The L-value for color decreased, whereas a- and b-values increased. In the texture profile analysis, 7%-added yacon showed significantly lower hardness, whereas 7% yacon powder showed the highest values for cohesiveness, springiness, and chewiness. The contents of sucrose, fructose, and glucose in yacon Sulgidduk were found to be 3%, 5%, and 7% by LC, respectively. Sucrose showed a decreasing trend with increased yacon powder content, but fructose and glucose increased with increased amount of yacon powder. For sensory qualities, taste/flavor, texture, hardness, and overall acceptability were not significantly different among the 0%, 3%, and 5% yacon powder samples.

• Biomolecules & Therapeutics
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• v.21 no.2
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• pp.153-160
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• 2013

We screened the pharmacological effects of a 50% ethanol extract of Yacon tubers and leaves on spermatogenesis in rats. As a result, we found that Yacon tuber extracts increased sperm number and serum testosterone level in rats. It has been reported that the crude extract of Yacon tubers and leaves contain phenolic acids, such as, chlorogenic acid, ferulic acid and caffeic acid by HPLC/MS analysis. We were interested in the contributions made by phenolic acid, particularly chlorogenic acid of Yacon tuber extract to the spermatogenic activity. After administering Yacon tuber extract or chlorogenic acid to rats for 5 weeks, numbers of sperm in epididymis were increased by 34% and 20%, respectively. We also administered ferulic acid, which has been reported to be a metabolite of chlorogenic acid and a constituent of Yacon tuber extract to investigate its spermatogenic activity in rats. Yacon tuber extract and ferulic acid increased sperm numbers by 43% and 37%, respectively. And, Yacon tuber extract, and chlorogenic acid showed significantly inhibition effect of testoeterone degradation in rat liver homogenate. We considered that the spermatogenic effect of Yacon tuber extract might be related to phenolic compounds and their inhibitory effect of testosterone degradation. Yacon showed the possibility as ameliorable agents of infertility by sperm deficiency and late onset hypogonadism syndrome with low level of testosterone.

• YAKHAK HOEJI
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• v.53 no.5
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• pp.250-258
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• 2009

Male reproductive function seems to have deteriorated considerably in the past 4 to 5 decades. It was observed a significant decline in mean sperm counts from $113{\times}10^6/ml$ in 1940 to $66{\times}10^6/ml$ in 1990; a fall of $0.94{\times}10^6/ml/year$. We reported that Yacon tuber extracts have spermatogenic effects in rat. In the present study, we tested the spermatogenic effect of Yacon tuber extracts in healthy male volunteers. Subjects were assigned randomly to the control group and the Yacon ethanol extracts administered group (each 12 subjects). And, placebo or Yacon tuber extracts (100 ml) were administered two times daily, by oral for 3 months. Sperm numbers, biochemical parameters and hormone levels were recorded before starting administration, then every month. The Yacon tuber extracts administered group showed significant time dependant increases in according to administration period. Especially, the numbers of sperm increased by 54% after 3 months of administration. And, in Yacon tuber extracts administered group, testosterone and estradiol level were significantly higher than placebo group. On the other hands, Yacon tuber extracts didn't show any toxicity in glucose and lipid metabolism and liver and kidney function. The results of the present study suggest that Yacon tuber extract is a possible therapeutic for the treatment of sperm deficiency.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.3
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• pp.378-385
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• 2012

This study carried out to investigate the effects of yacon powder on yellow layer cake made with weak flour. After making yellow layer cake with yacon powder, water activity, crumb texture, crumb color, and sensory characteristics were investigated. After 1 day of storage, Aw value of control cake with weak flour did not show any significant differences, whereas those with 2, 4, and 6% yacon powder showed a significant increase in Aw. During storage, the Aw values of yellow layer cakes containing yacon powder decreased. Hardness and gumminess of yellow layer cakes containing yacon powder decreased compared to those of control, whereas springiness and cohesiveness of yellow layer cakes increased compared to those of control. Hardness, springiness, cohesiveness, and gumminess all increased with storage time. Further a higher percentage of yacon powder was associated with lower L and b values as well as a higher a value. The micrographs of yellow layer cakes with yacon powder showed slightly coarser porosity than that of control. The results of the sensory test showed that the overall acceptability of 2% yacon powder cake was the highest.

• Korean journal of food and cookery science
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• v.26 no.3
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• pp.263-271
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• 2010

The purpose of this study was to measure the antioxidant activity of yacon root and to manufacture yacon pickles for commercialization as a functional food. The total phenol content in yacon roots were the highest, 29.96 mg GAE/ 100 g, in the ethyl acetate fraction and the DPPH radical scavenging activity and ABTS radical scavenging activity was 37.07%, and 91.60%, respectively, in the ethyl acetate fraction. The optimum recipe for the pickling solution was determined to be vinegar, water and high fructose corn syrup, at 34%, 22% and 44%, respectively. The quality characteristics of yacon pickles using this solution were monitored during storage at $25^{\circ}C$ for 43 days. The pH value decreased to 2.98 (42 days) during storage and $^{\circ}Brix$ gradually increased during storage. The L-value decreased significantly during storage but there were no significant changes detected in the a and b values. No significant changes were detected in the hardness of the yacon pickles. According to the sensory evaluation, no significant changes in taste, texture and overall acceptance of yacon pickle were observed during storage. These results indicated that yacon was an excellent functional food in terms of its antioxidant activity and that pickling might be a promising methods to maintain the taste and quality of yacon during storage.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.3
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• pp.374-381
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• 2013

The purpose of this study was to analyze the antioxidant effects and antimicrobial activity of extracts from yacon powder. The total polyphenol contents of yacon powder extracted with methanol was 38.5 mg/g, while extracted with water was 24.0 mg/g. Extractions with methanol were therefore more effective than with water. The total flavonoid contents of yacon powder extracted with methanol was 9.2 mg/g, while that with water was 7.8 mg/g. The electron donating ability of yacon powder extracts, natural antioxidant, and artificial antioxidant at 1.0 mg/mL arranged in order of decreasing concentration were ascorbic acid (98.7%) > BHT (44.7%) > methanol extract (12.1%) > water extract (7.8%). Nitrite-scavenging ability of yacon powder extracted with methanol at pH 1.2 was 13.1%, while that of powder extracted with water at pH 1.2 was 6.8%. And, the hydroxyl radical scavenging activities of yacon powder with methanol at 5 mg/mL was 40.2%. The antimicrobial activity of yacon powder extracted with methanol could be detected on Bacillus cereus ($10,000{\mu}g/disc$) and Staphylococcus aureus ($10,000{\mu}g/disc$).

• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.600-606
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• 2010

The objective of this study was to develop functional rice coated with yacon roots extracts and to evaluate the antioxidant properties and physiological activity of rice coated with yacon extract. The washed rice was coated by spraying yacon extract at 10, 20, 30, and $40^{\circ}Brix$ and dried at room temperature. The moisture contents, color changes, antioxidant properties as total polyphenolics and DPPH radical scavenging activity and instrumental texture property and sensory evaluation change in the yacon root extracts coated rice and uncoated cooked rice were observed during 3 days of storage. Increasing the coating concentration was associated with lower color values(L value) and moisture contents. Total phenolics and DPPH radical scavenging properties generally increased in the cooked rice coated with yacon root extract more than the control (non-coated rice). However, D-20($20^{\circ}Brix$ of the yacon root concentration) resulted in better textural properties and sensory overall acceptability in cooked rice on 0 and 3 storage days. It was concluded that the optimum coating ration of rice and added functional yacon rice were $20^{\circ}Brix$ and 7% respectively, in proportion to the total weight of raw rice.

• Journal of the Korean Society of Food Culture
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• v.28 no.1
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• pp.107-113
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• 2013

Yacon (Smallanthussonchifolius) is a root crop that contains high amounts of fructo-oligosaccharides (FOS). FOS has a sweet taste, is low in calories, and is known to promote intestinal tract health. In this study, various yacon concentrates were substituted for sugar in white pan bread to obtain healthy benefits from the use of FOS. The quality characteristic changes during storage of the white pan breadswith 0, 25, 50, 75 and 100% of added yacon concentrates instead of sugar were investigated. During storage, the water contents and water activities of the breads made with high amounts of yacon concentrates changed less than in those made with only sugar. The hardness and chewiness of the breads made with high amounts of yacon concentrates had lower values than those made with only sugar. Thus, bread made with yacon concentrates might exhibit increased moisture retention and decreased aging velocity. The substitution of yacon concentrates for sugar in pan bread improved the bread quality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.921-926
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• 2012

The objective of this study was to investigate the quality characteristics of blanched and non-blanched yacon (Smallanthus sonchifolius) soaked in Doenjang sauce. The yacon was treated by blanching ($100^{\circ}C$, 4 min), then soaked in Doenjang sauce at $20^{\circ}C$. The pH and total acidity of blanched yacon were not changed significantly after 42 days of soaking. But, the pH and total acidity of non-blanched yacon were rapidly increased and decreased, respectively. The salinity of blanched yacon was higher than that of non-blanched yacon until 35 days. Also, the $Brix^{\circ}$ of blanched yacon was higher than that of non-blanched yacon from 7 days to 35 days. Textural properties of both non-blanched and blanched yacon showed that hardness increased until 21 days but decreased afterwards. The total polyphenol contents of non-blanched yacon decreased after 14 days, but blanched yacon remained constant. The DPPH radical scavenging activity of both blanched and non-blanched yacon decreased gradually as aging continued in the Doenjang sauce. There were no significant differences in sensory characteristics between blanched and non-blanched yacon soaked in Doenjang sauce.

• Culinary science and hospitality research
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• v.20 no.3
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• pp.100-112
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• 2014

This study investigates the characteristics of cookies added with yacon. The addition of yacon powder did not affect the density of the cookies and decreased pH level. The moisture content was the highest in the cookies with 12% of yacon. Spread ratio was the highest in the cookies containing yacon powder. The loss rate and leavening rate of the cookies decreased with increasing amounts of yacon powder. Lightness and yellowness decreased significantly while redness increased significantly with a high content of yacon powder in the formulation. The hardness of the control group was higher than that of the cookies prepared with different levels of yacon powder. The antioxidant activity was estimated by DPPH free radical scavenging activity and the total phenolic acid content in yacon powder and cookies. The consumer acceptability score for the 6% yacon cookie group ranked significantly higher than the other groups in overall preference, appearance, flavor, taste and color. Through this experiment, this study exhibited both the functional and health based benefits of yacon when it is added to cookies and confirmed the development feasibility of yacon cookies considering consumer satisfaction.