• Journal of the Korean Society of Food Culture
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• v.27 no.1
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• pp.82-88
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• 2012

In this study, the effects of yacon (Smallanthus sonchifolius) leaf on the quality characteristics of cookies were examined. In order to investigate its effects, four different amounts (0%: Control, Y-0.5, Y-1.0, Y-1.5) of yacon leaf powder were added to the cookie dough. Among the physicochemical and sensory characteristics, the density and pH of the dough, spread factor, color value, firmness, consumer acceptability, and Pearson's correlation coefficients were measured. Although there was no significant difference in pH of the doughs among the groups, density significantly decreased with increasing amount of yacon leaf powder (p<0.05). While the L, a, b values, and hardness decreased significantly, DPPH free radical scavenging activity increased significantly as the content of yacon leaf powder increased (p<0.05). Overall acceptability, appearance, taste, and texture between the control and Y-0.5 groups showed no significant differences. This study suggests the possibility of yacon leaf as an ingredient that increases the functionality of cookies.

• Korean Journal of Plant Resources
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• v.28 no.6
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• pp.734-742
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• 2015

The purpose of this research was to find the most appropriate process for making yacon leaf tea. We applied both green tea and black tea brewing and fermenting methods for producing yacon leaf tea. This research included consumer test and descriptive analysis of professional trained panel on yacon tea tastes and flavors. Both consumer test and descriptive evaluation preferred yacon tea produced by black tea brewing and fermenting methods because it tasted less bitter and had a sweet, delicate taste. According to orthogonal transformation resulting from varimax rotation, first principal component was positively affected by black tea brewing and fermenting methods, while it was negatively affected by green tea brewing and fermenting methods. As a result, the study concluded black tea brewing and fermenting methods were appropriate for producing yacon leaf tea.

• YAKHAK HOEJI
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• v.57 no.4
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• pp.241-249
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• 2013

We reported previously that the extracts of Yacon tuber and leaf have spermatogenic activity and testosterone level increasing effect in men. The aim of this study was to investigate the mechanism of testosterone level increasing effect of Yacon tuber and leaf extracts. In this study, we found that Yacon leaf extracts and chlorogenic acid, a constituent of Yacon extracts showed significantly inhibition effect of testosterone degradation in rat liver homogenate. We suggest that this could be a part of direct mechanism about increasing effect of testosterone level. Futhermore, we evaluated the inhibition effect of testosterone metabolism of Torilis japonica and Coix lacryma-jobi have been reported as $5{\alpha}$-reductase inhibitor. The inhibition ratio of testosterone metabolism of these were Torilis japonica>Coix lacryma-jobi>Yacon. We also evaluated the benign prostatic hyperplasia (BPH) score with the preparation composed of these natural product, Yacon pill. It showed the decreased the BPH score in men. Rats with BPH showed significantly increased dihydrotestosterone (DHT) levels in the serum; however, Yacon pill extracts treated rats showed significant reduction of DHT levels compared with the BPH group. Conclusively, Yacon pill showed the possibility as ameliorable agents of BPH symptoms.

• Korean Journal of Plant Resources
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• v.30 no.3
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• pp.311-317
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• 2017

This study was conducted with the aim of evaluating the antibiotic effects of leaves, stems, and roots in yacon (Smallanthus sonchifolius). Antibacterial activity of leaf extract by disk diffusion method with Bacillus subtilis and Escherichia coli respectively showed 13.3 and 13.75mm diameters of clear zone. There was no significant difference between the stems and leaves. The minimum inhibitory concentration of leaves' heating and agitation extraction showed a restrain of strain at 1mg/ml, but the stems and root extract did not appear. Yacon is a functional antibacterial material, and methanol extraction is more effective than water. This research was to investigate the growth stage of collection has the most effective antibacterial effects. It has collected yacon's leaves from June to October, which is an appropriate time for collection right before reaping. Yacon leaf has antibacterial effects on Bacillus subtilis, Escherichia coli, Enterococcus faecium, and Salmonella enteritifis. There were no significant differences by the growth stage of collection. Leaves collected in July are high in phenol which helps in sulfating activity works well considering the high scavenging capability of DPPH. Leaves collected in September are high in total flavonoid.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.545-552
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• 2012

To improve a low-salted yacon pickle, the change of quality characteristics during the storage of yacon pickles were investigated at $18^{\circ}C$ for 50 days using two-way ANOVA. One factor that was added was the leaf-mustard and pepper (A), the other was storage time (B). The leaf-mustard and pepper were added to increase the yacon pickle's taste, flavor, and properties. The sugar content, total acidity and salinity were significant for factor A and B. With the interaction effect of the two factors, yacon pickles increased as storage time increased. The L value was not significant for factor A but significant for factor B. The a and b values were significant for the two factors. All Hunter's color value had the interaction effect. The shearing force was not significant for each factor, and yacon pickles did not show a softening effect. In the results of the sensory evaluation, color, taste, and overall preference were significant for factor A and B, yet the flavor was only significant for factor B. The texture was not significant at all. In the overall preference, yacon pickles were higher at 30 and 40 days and also, had the interaction effect. Yacon pickles were not above the 3.0% of salinity.

• Biomedical Science Letters
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• v.26 no.3
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• pp.201-209
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• 2020

The effect of mulberry leaves and yacon tuber extracts (MYE) on antioxidant was tested in this study. The present study investigated the in vivo effects of the anti-oxidative effect of MYE on catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GSH-Px), and thiobarbituric acid reactive substances (TBARS). The seven-day acclimation of the mice was divided into six groups: Normal diet group (NOR), high fat diet group (HFD), high fat diet with 0.5% hydroxycitric acid group diet group for positive group (HHCA), high fat diet with 1% mulberry leaf and 1% yacon diet group (MYE-1), high fat diet with 3% mulberry leaf and 3% yacon group (MYE-3) and high fat diet with 5% mulberry leaf and 5% yacon group (MYE-5). The effect of serum antioxidant in the catalase of MYE-1, MYE-3, and HHCA comparing to HFD by 31.0%, 27.7% and 45.2%, respectively (P<0.05~0.01). The effect on hepatic antioxidant in the catalase of HFD was significantly increased 3.7 (77.3%) times than that of NOR (P<0.01). But, the activities of catalase were decreased significantly in MYE-1, MYE-3, MYE-5 and HHCA by 21.7%, 24.2%, 24.9%, and 28.8% compared to HFD, respectively. GSH-Px was significantly decreased in MYE-1, MYE-3, MYE-5 and HHCA by 15.5%, 37.1%, 23.4%, and 23.7% compared to HFD, respectively (P<0.05). The activities of CAT, SOD, GST, GSH-Px, and TBARS were more significantly decreased in MYE-1 and MYE-3 than those of HFD and HHCA. MYE have shown significant effects on anti-oxidative function against high fat diet.

• Natural Product Sciences
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• v.14 no.2
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• pp.73-80
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• 2008

The authors screened the pharmacological effects of 50% ethanol extracts of Yacon on spermatogenesis in rats. Numbers of sperm in animals treated with 25, 50, or 100 mg/kg/day for 6 weeks of Yacon tuber extracts (YTE) were approximately 1.51, 1.61 and 1.78 times higher, respectively, than in the untreated control group. Moreover, the spermatogenic effect of Yacon leaf extract was found to be $1.03{\sim}1.38$ times higher than that of YTE. The ameliorative effect of Yacon tuber extracts on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced toxicities in the rat were also investigated. Rats were assigned to three groups (6 rats/group), a control group, a TCDD exposed group, and a group treated with Yacon tuber extract (YTE) after TCDD exposure (TCDD/YTE group). 40 ${\mu}g/kg$ of TCDD was injected i.p., and 200 mg/kg/day of YTE was also administered for 4 weeks by oral gavage. The TCDD/YTE group showed a significant increase in sperm number as compared with the TCDD exposed group. In conclusion, TCDD induced testicular toxicity was significantly ameliorated by YTE. The results of the present study suggest that Yacon extract is a possible therapeutic for the treatment of spermatogenic disorder.

• Korean Journal of Plant Resources
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• v.9 no.3
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• pp.274-278
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• 1996

This study was conducted to examine the dry matter production and leaf photosynthesis under different fertilizer application in Yacon(Polymnia sonchifolia)plants. Under field conditions, dry matter production of stable mature application plot(S-1) was much larger than non-treated control plot(CTL), but bulb dry weight of 10kg nitrogen application plot per 10a (N-10) was not differentiated from CTL. The maximum photosynthetic rates increased in Yacon plants grown at S-1 while in the rates of CTL reduced under glasshouse in the same treated pot condition. The optimum temperature for the highly photosynthetic rates is about $34{\pm}3^{\circ}C$, and the rates did decrease by stomatal resistance below 28℃. The estimated light saturation point was $1200{\mu}mol{\cdot}m^{-2}s^1$. The results of this study indicate that soil conditions were highly related to dry matter production and leaf photosynthesis rate in Yacon plants.

• Biomedical Science Letters
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• v.26 no.2
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• pp.75-84
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• 2020

We evaluated the effect of anti-obesitic activity of MYE (mulberry leaf + Yacon tuber) extracted from Morus alba as muberry leaf and Smallanthus sonchifolia as yacon. 1%, 3%, or 5% of MYE were treated to Sprague-Dawley rats exposed to a high-fat diet. MYE treated rats were suppressed weight during four weeks, and they lost weight significantly after six weeks. Common blood chemistry panels related to liver function revealed significant improvement in the MYE-treated groups. The expression of leptin as indicators for obesity was decreased in perirenal fat. Such results indicate that MYE could be a promising candidate for the improvement of obesity. In addition, MYE effected on deceased glucose metabolism, reducing the activities of glucose-6-phosphate dehydrogenase (G-6-PDH) and glucokinase related to glycogen synthesis. The fatty liver was observed in high-fat diet-treated rats, resulting from increased number of adipose cells and Ito cells. However, this pathologic change was significantly improved by administration of MYE. MYE have significant effects on antioxdative function and glycometabolism against high fat diet. Thereby, it seems that MYE prevent fatty liver by high-fat diet. Thus it is suggested that MYE would be worth being developed as an biofunctional food to prevent undesirable effects caused by obesity.

• Biomedical Science Letters
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• v.26 no.2
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• pp.101-108
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• 2020

There has been a lot of interest in medicinal effects for hyperlipidemia from the natural product since the therapy of atherosclerosis has emerged as social concern. Rats were acclimated to the feeding environment for one week and induced to obesity with high fat diet during 4 weeks until their body weight were more than 30% of normal range. To evaluate the effect of hyperlipidemia of mulberry leaf of Morus alba and yacon tuber of Smallanthus sonchifolia extracts (MLYT), 1%, 3%, 5% of MLYT were treated to Sprague-Dawley rats. Aspartate transaminase (AST) was significantly increased 26.2% in high fat diet group (G2) compared to normal diet group (G1) (P<0.05). But AST were significantly decreased in high fat diet with 0.5% hydroxycitric acid diet group (G3) and all the MLYT treated groups compared to G2. Total cholesterol, low-density lipoprotein (LDL), triglycerides and phospholipids were observed significant improvements in the MLYT-treated groups (P<0.05). These improvements in liver and feces were further supported by the lipid content. MLYT remarkably suppressed the level of lipid peroxidation caused by high-fat diet in rats. The level of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase activity. As a result, the proper combination of mulberry leaves and yacon tuber extract will have a synergistic effect on hyperlipidemia. These results indicate that MLYT could be a candidate for the improvement of hyperlipidemia.