• Journal of Life Science
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• v.20 no.1
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• pp.40-48
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• 2010

This study was carried out to investigate the physicochemical and functional properties of Yacon (Polymnia Sonchifolia) powder. The proximate composition of Yacon powder as a dry matter basis was 3.53% moisture content, 1.13% crude protein, 0.40% crude fat, 0.79% crude ash, 1.63% dietary fiber and 92.52% carbohydrate. The major free sugars were identified as fructose and glucose. Analysing total amino acids, 18 kinds of components were isolated from Yacon powder. The essential amino acid contained in Yacon powder accounted for 28.40% of total amino acid, while the non-essential amino acid accounted for 73.61%. Analysing total fatty acids, only 2 kinds - palmitic acid and lauric acid - were detected. Oxalic acid was the major organic acid. The contents of vitamin A, vitamin C and vitamin E were 0.057 mg%, 0.670 mg% and 0.001 mg%, respectively. The mineral contents of Yacon powder were in the order of Zn

• Korean Journal of Medicinal Crop Science
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• v.15 no.1
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• pp.17-20
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• 2007

This study was conducted to investigate the effect of various composts and NPK fertilization rates on the growth of yacon (Polymnia sonchifolia POEPP). Fertilization of used soil was low. Mean temperature of July was higher than that of normal year, but those of another months were same or the lower. The yield of the no-compost plot was higher by 74% than the no-fertilization plot. Increased NPK fertilization rates of bark compost and organic fertilizer plots increased the growth and yield of yacon. The yield of bark compost 1.5 times plot was highest by 6,905 ㎏/10a. The chemical contents of leaves in the various compost and NPK fertilization rates were not normal tendency, and also that of no-compost plot was not difference to the NPK fertilization rates plot.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.249-258
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• 2017

The purpose of this study was to investigate the effects of envrionmental factors on the ecological responses, yield, and quality properties and physicochemical characteristics of yacon cultivated in various regions of Korea. Experiments were carried out in eight regions from 2010 to 2013. The temperature range in Jinbu, Bonghwa, Cheolwon, and Gangneung during the growth period of yacon cultivation was $17.5-24.6^{\circ}C$. The total yield and marketable yield of tuberous root in Jinbu were 4,065 and 3,196 kg/10a, respectively. The sugar content of yacon tuberous roots comprised 0.11-0.20% fructose, 0.11-0.37% glucose, 0.39-0.68% sucrose, 0.07-0.37% reducing sugar, and 7.03-9.62% fructo-oligosaccharides. The content of fructo-oligosaccharides, which is a functional substance, was the highest in yacon cultivated in Jinbu. Based on the productivity and functional fructo-oligosaccharides, the optimum areas to cultivate yacon are Jinbu and Bonghwa, which are located in the middle-highland zone (500-560 m) and have a suitable growth temperature of $18-25^{\circ}C$. The results of the present study indicate that temperature could be the factor with the greatest influence on the root growth of yacon.

• Journal of Life Science
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• v.22 no.7
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• pp.904-911
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• 2012

Yacon has been used in folk medicines as a medicinal tea for hypoglycemia treatment. In a recent study described herein, antioxidative, antibacterial, antifungal activities, and cell-protective functions of yacon leaves have been reported. To evaluate the effects on fibrosis on pancreatitis, the efficacy of 1% of yacon extract (YE) on dibutyltin dichloride (DBTC) (8 mg/kg)-induced pancreatitis in rats was examined. On the 21st day after the DBTC treatment, a large increase in collagen was observed in the pancreas in the DBTC-treatment group (DT). But this was noticeably decreased with YE. In relation to the expression of COX-2, there was no response or a very weak response in the pancreas of the control group (CON). However, in DT, strong expression of COX-2 was observed in the pancreas on the 14th day, and COX-2 was present in inflammatory cells in the pancreas of the DT, especially on the 21st day. The expression was decreased for YE compared with DT. A remarkable increase in TGF-${\beta}1$ expression was observed in inflammatory cells in the pancreas in DT on the 21st day, whereas the expression was not found in YE after 21 days. However, on the 21th day, TGF-${\beta}1$ expression was increased in acinar cells of YE compared with DT. VEGF expression was very similar to the expression of in the pancreas. These results suggest that YE has an inhibitory effect on DBTC-induced pancreatic fibrosis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.2
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• pp.149-155
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• 2017

To establish cultivation areas for the stable production of yacon, this study investigated the productivity and functional component contents of yacon in eight regions of Korea from 2011 to 2013. The results of principal component analysis using these data were as follows. A survey of 16 agricultural traits and meteorological data in the eight yacon cultivation areas showed that five factors (average temperature, maximum temperature, minimum temperature, frost-free days, and fructooligosaccharide content) were highly significant at the p < 0.001 level. Among the 16 agricultural traits and meteorological data used in the main component analysis of yacon cultivation areas, approximately eight contributed to the first principal component, and approximately four contributed to each of the second and third principal components. In particular, factors related to productivity, fructooligosaccharide content, and temperature change were considered important criteria for the classification of cultivation areas. The cultivation areas were divided into three groups by principal component analysis. In Group I, containing the Jinbu and Bonghwa areas in the mid-highland region at 500-560 m above sea level, the product yield was the highest at 2,622-3,196 kg/10a, the fructooligosaccharide content was also the highest at 9.04-9.62%, and the mean temperature was $17.3-18.5^{\circ}C$. In Group II, the areas Suncheon, Okcheon, Yeoju, and Gangneung, at 20-180 m above sea level, had the lowest yield, relatively lower fructooligosaccharide content, and the highest temperature. The areas in Group III showed values intermediate between those of Group I and Group II. For the different yacon cultivation areas, the product quantity and fructooligosaccharide content differed according to the environmental temperature, and the temperature conditions and number of frost-free days are considered important indicators for cultivation sites. Therefore, in terms of producing yacon with high quality, cultivation at 500-560 m is considered to give a higher yield and functional fructooligosaccharide content.

• Food Science of Animal Resources
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• v.32 no.2
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• pp.190-197
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• 2012

This study was performed to evaluate the extraction method (Yacon ethanol extracts; YEE, Yacon pressed extracts; YPE) and various levels (0.05-1.0%) of Yacon (Polymnia sonchifolia) on antioxidant and antimicrobial activities. In linoleic acid emulsion of YPE, there were higher iron chelation activity and antioxidant activity than those of YEE (p<0.05). A 1,1- diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity and reducing power of both extracts showed a higher rate at 0.5% level. Ground pork patties, which contain 0.5% YEE and YPE, were manufactured and BHT (0.01%) was used as a reference. Physicochemical properties and microbial counts of ground pork patties, containing a different type of Yacon, were evaluated during the 14 d of storage at $4^{\circ}C$. A pH level, and lightness (Hunter L), as well as the yellowness (Hunter b) values of treatments were not different from those of the control (p>0.05), but increased during storage, at $4^{\circ}C$. Lightness values of ground pork patties, with Yacon extracts, showed the highest. TBARS value of ground pork patties that contains Yacon increased with increased storage at $4^{\circ}C$ (p<0.05), and pork patties with YPE or YEE retarded the lipid oxidation, during refrigerated storage, as compared to that of the CTL. Thus, YPE could be used as a potential possibility to inhibit the lipid oxidation of processed meats, during the refrigerated storage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.240-244
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• 1993

Yacon(Polymina sonchifolia POEPP), an indigenous Andean natural resource food plant, was imported as a new root crop from New Zealand in 1986. However the chemical composition and planting system of it have not been research in Korea. The experimental results for the optimum planting densities and mulching effect are as follows. Height of the main stem of yacon was grown linear from July to October, is showed more fast growth as density increased, and showed highest in 70 ${\times}$ 55cm density. The tiller was bubed 3 month after planting but there was no significant difference among mulching, non-mulching condition and planting density. The fresh weight of root of mulching condition was heavier than that in non-mulching condition and 70 ${\times}$ 40cm mulching condition. In mulching treatment, number of roots in dense planting were more than that in sparse planting. The effect of mulching was not shown significantly in root diameter and root length.

• 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.

• Korean Journal of Medicinal Crop Science
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• v.7 no.3
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• pp.205-212
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• 1999

This study was carried out to examine the effect of polyethylene film color and removing time of the mulching film in yacon (Polymnia sonchiiolia Poepp. & Endl.). The plant height on nonmulching was smaller about 10 cm or larger with 112cm than on other mulches ranged with $134{\sim}139$ cm at harvesting, and other characters examined were similar to that of plant height. The weight of tuberous root per plant was heavier on mulches ranged with $0.79{\sim}0.91$ kg than on non-mulching with 0.61 kg. Among the kind of mulches, plant height was the tallest with 139 cm in combination and declined in order of transparent, green and black polyethylene films. Yields among colored polyethylene films were the heaviest with 0.91 kg per plant in combination, 0.88 kg in black and 0.84 kg in green. In growth and yield full mulching untill harvesting was more effective than the other removed mulching treatments. It was effected on growth promotion at early growth stage, soil temperature and water preservation.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.9-18
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• 2013

The aim of this study is to provide the basic data for yacon [Samallanthus sonchifolius (Poepp. & Endl.) H. Robinson] in dietary food. The nutritional compositons, such as protein, ash, carbohydrate, dietary fiber, vitamin and fructooligosaccharide, were analyzed for 4 yacon germplasm lines. Yacon has low calories with only 46~56 kcal/100 g. The contents of water, fat, ash, protein, carbohydrate and dietary fiber were ranged 85.9~86.8%, 0.1~0.2%, 0.2~0.3%, 0.5~0.7%, 12.2~13.1% and 1.05~1.14%, respectively. The iodine-starch test did not show any color or precipitation reaction, which indicates that yacon has no starch content. However, in the absence of starch, yacon is rich in fluctooligosaccharide, which is between 9.6~11.1%. Maltose is present in the larger amount, followed by sucrose, glucose, and fructose in terms of free sugars. The analysis of minerals revealed that yacon contains potassium in the larger amount of 141~176 mg/100 g F.W., followed by magnesium at 8.2~10.6 mg, calcium, and sodium representing the least present mineral. Yacon proved to have a total of 17 types of amino acids, which are between 404.0~581.8 mg per 100 g of yacon. Glutamic acid, the main sweetening component, is present in the large amount of 94.0~182.2 mg/100 g F.W., followed by aspartic acid, arginine, and alanine. The proportion of the essential amino acid was 24.8~33.6%. Results of analysis also showed that yacon contains 0.001~0.024 mg, 0.03~0.11 mg, 0.02~0.3 mg, 0.3~0.4 mg and 14.1~20.6 mg of ${\beta}$-carotene, thiamin, riboflavin, niacin, and ascorbic acid, respectively. It is also likely to be highly used as functional food material in the future because it is abundant in both fluctooligosaccharide and antioxidants which are important functional components.