• Research in Plant Disease
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• v.12 no.3
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• pp.235-239
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• 2006

Since the cultivation of resistance cultivar is essential for organic agriculture, Phytophthora late blight resistance of 16 advanced potato clones obtained from the potato breeding laboratory at the National Institute of Highland Agriculture was evaluated. Resistance of the clone was examined through artificial inoculation in the laboratory and in the field. Dominant isolates of the pathogen in Gangwon province produced abundant sporangia on leaves of most clones showing susceptibility. The number of sporangia ranged from $10^{7{\sim}8}sporangia/ml$ in the susceptible clones at 7 days after inoculation. However, one clone is resistant in organic farming fields. Disease incidence was 2.3% using the resistant clone. The area under disease progress curve(AUDPC) was 75.5. Contrarily, disease incidence of the susceptible variety was 100% and the AUDPC was 1773.5 during the same cultivation period. The resistance clone named as 'Haryeong' is considered suitable for organic potato cultivation in Gangwon province in Korea.

• Preventive Nutrition and Food Science
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• v.22 no.3
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• pp.246-250
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• 2017

This study was performed to investigate the quality characteristics of noodles made from four different potato varieties: Atlantic, Go-un, Sae-bong, Jin-sun, and wheat flour. Quality characteristics of five noodles were analyzed by general components analysis, cooking quality (rate of water absorption, cooking loss, and volume increase), and mechanical textural properties. Some variations existed in wheat- or potato-based noodles for the general components analysis, but no clear trend was observed. Higher values in the rates of water absorption, cooking loss, and volume increase were observed for the wheat flour noodle, while some variations were observed for potato noodles depending on the variety. The wheat flour noodles exhibited higher values of textural characteristics obtained from the texture profile analysis, except for adhesiveness. Higher gluten contents as well as lower ash contents in the wheat flour noodles compared to the potato noodles are thought to be the two key factors contributing to this finding.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.3
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• pp.375-383
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• 2009

This study was conducted to measure the total polyphenol contents and DPPH radical scavenging activities of different potato plants parts, varieties, and grades, and by distribution and different cooking conditions. The results were as follows. For the plant parts, total phenolic content and DPPH radical scavenging activity were highest in the flowers followed by leaves and stems, respectively. Among 5 potato varieties, 'Jasim' had the highest DPPH radical scavenging activity and the activity of its pulp was lower than that of its cortex(peel). Regardless of potato grade, the cortexes(peel) of samples had two-fold higher DPPH radical scavenging activity than pulp, and the Grade SS potato had the highest phenolic content. It was also found that the bud ends and stem ends had comparably larger amounts of phenolic compounds in horizontally cut potatoes. Finally, the descending order for DPPH radical scavenging activity, according to different cooking conditions, was as follows: gas oven range-baking, frying, microwave-heating, sauteing, boiling in 1% saline solution, steaming, and boiling in 3% saline solution.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.39-39
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• 2017

In Asia, sweet potato (Ipomoea batatas) is a very important crop for starch production. Approximately 74.3% of the total sweet potato production quantity is produced in Asia (FAO, 2014) and China is the largest producer of sweet potato. Post-harvest management is particularly important because it is difficult to maintain the quality as well as quantity of sweet potatoes. Despite the importance of post-harvest management, researches on sweet potato have been focused on production-related study such as breeding of new variety, improved techniques of cultivation, so there is limited research on storage after harvest. Curing is a normal practice after sweet potato harvest to promote wound healing and extend postharvest storage life. In Korea, harvested sweet potatoes are usually cured for 4 to 7 days at $30-33^{\circ}C$ and 80-95% relative humidity within one week. Since the optimum storage temperature of sweet potato is regarded as $15-20^{\circ}C$, additional facilities and costs are required to raise the temperature for curing. However, the majority of small farmers do not have the capacity to provide additional facilities and costs. This study was initiated to suggest a new curing method to accelerate the wound healing by applying chemical oxidation to the wound surface of sweet potato. Oxidative stress is known to play an important role in the synthesis of secondary metabolites including lignin. In addition, chemical oxidation can be applied to prevent spoilage caused by microorganisms. Powerful gaseous oxidant with excellent penetration ability and superior sterilization effect was selected for this study. Lignification, weight loss, and spoilage rate of artificially wounded sweet potatoes were investigated after oxidant fumigation. There were clear differences in morphological analysis such as lignification pattern, lignin deposition color, and continuity of lignified cell layers between oxidant-fumigated sweet potatoes and control. These results show that gaseous oxidant can be used to supplement or replace the curing practice, to improve shelf-life as well as curing cost reduction.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.437-442
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• 1992

In order to develop color of potato chip made from Superior variety and Irish Cobbler variety, various conditions on NaCl and $CaCl_2$ contents, heat treatment and soaking time were applied. The content of reducing sugar decreased by $30{\sim}40%$ in blanching without NaCl and $CaCl_2$. In NaCl soaking case, reducing sugar content decreased by $15{\sim}30%$, however, partial colorization was appeared that the sample turned to brown. In the sample that were soaking in NaCl solution and heat treated, reduction of reducing sugar was 40% and desirable time for heat treatment was 5 min and 7 min. In the sample treated $CaCl_2$ solution, reduction of reducing sugar was $25{\sim}30%$ and then color was not acceptable. In the sample soaking $CaCl_2$ solution and heat treated, reducing sugar content rapidly by 50% and the color development was the most ideal.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.345-345
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• 2017

In order to reduce rice cultivation area in paddy fields and to increase domestic self-sufficiency of imported upland grain, it is necessary to increase double cropping area of upland crops in paddy field in accordance with decrease of rice consumption in Korea. The double cropping of spring potato-summer grain maize can be combined because of enough growing season in the southern plain of Korea. Spring potato, which is profitable, can be planted in the late February and harvested in the late May as the main crop. Subsequent grain maize can be planted in early June and harvested in November (maturity in the early October). Spring potato (variety Soomi) yielded $2,544kg\;10a^{-1}$ (tuber) when planted in late February, 2016. When maize was planted in June as the second cropping crop, though growth of plant decreased much, grain yield decreased slightly compared to normal planting in April or May. There was enough time to dry maize ear in the field after maturity before harvesting, which saved labor and time for grain drying, since there is no autumn planting at the double cropping of spring potato-summer grain maize. When grain maize (variety Gwangpyeongok) was planted in the early June (June $10^{th}$), average grain yield of above $860kg\;10a^{-1}$ over 2 years of 2015 and 2016 was obtained, and the annual total yield (potato tuber + maize grain) of 3,400 kg $10a^{-1}$ was obtained. The result indicates that the double cropping of spring potato-summer maize using paddy fields in southern plain of Korea, could contribute to the self-sufficiency of upland crops through the maximum production.

• Journal of the Korean Society of Tobacco Science
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• v.3 no.2
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• pp.129-130
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• 1981

The potato tuberworm, Phthorimaea operculella, is an occasional pest to tobacco plants in southern regions of Korea. In order to screen effective pesticides against the worm in tobacco leaves, pot and field experiments were carried out in 1981. In the pot experiment with a tobacco variety, Hicks, several effective organic phosphates (Dimecron- LQ 50, Dursban-WP 25, Ekalux-EC 25. Elsan-EC 47.5, and EPN-EC 45), out of 9 Pesticides tested, were solecte4 from their high mortality of more than 90%. Among these Pesticides Ekalux- EC 25 and Elsan- EC 47.5 were recommended to tobacco growers from their excellent efficacy in the field experiment with a tobacco variety, Burley 21.

• Korean journal of food and cookery science
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• v.27 no.2
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• pp.19-29
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• 2011

Sweet potato powders made from eight Korean varieties, including purple-fleshed, orange-fleshed, and commercial dry type sweet potatoes, were investigated for physicochemical and pasting properties to develop processed food. Crude protein and lipid contents of Shinjami and Borami were higher than those of other varieties. The lightness value of raw sweet potato flesh was the highest value in Shinchunmi, and the lowest in Shinjami. Using the color difference (${\Delta}E$), color similarities compared to the white plate occurred in the following order; purple-fleshed > orange-fleshed > commercial dry type sweet potatoes. Total and damaged starch contents were significantly different (p<0.05). Total starch content of sweet potatoes was higher in commercial dry sweet potatoes (61.89-70.46%), particularly Shinchunmi (70.46%) but lower in orange-fleshed sweet potato (48.87 and 49.53%, respectively). Water binding capacity of Yeonwhangmi, swelling power and solubility of Shinyulmi were the highest values (174.70, 25.54 and 87.49%, respectively) among them (p<0.05). But oil absorptions of Shinyulmi and Shinchunmi showed lower values (97.08 and 97.54%, respectively). All sweet potato powders had an A type x-ray diffraction pattern. The initial pasting temperatures of sweet potato powders ranged from 69.50 to $75.95^{\circ}C$ and the amylolytic enzyme in sweet potato powder lowered pasting viscosity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.954-958
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• 1994

The bleaching effect of chlorophyll a by two lipoxygenase isoenzymes (LOX-1, LOX-2) isolated from potato tuber(variety DEinma ) was studied. In the presence of LOX-1 or LOX0-2 with linoleic acid chlorophyll a bleaching occurred during two isoenzymes-mediated oxidation of linoleic acid. Chlorophyll a bleaching porceeded with decreasing in the formation of conjugated dienes form linoleic acidyb LOX-1 and LOX-2 . In the presence of chlorophyll a, LOX-2 showed a markable decrease inproduction of conjugated dienes from linoleic acid and a higher chlorophyll a bleaching activity. compared with LOX-1. These results suggest chlorophyll-bleaching reaction required intermediates formed during the peroxidation of linoleic acid by lipoxygenase isoenzymes, thus preventing formation of conjugated dienes.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.51-55
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• 2015

Four varieties of the Korean sweet potato, Yeonmi, Jeungmi, Shincheonmi, and Shinyeulmi, were chosen to prepare the distilled koguma-soju (sweet potato-soju). The relationship between the flavor of the koguma-soju and the content of monoterpene alcohols (MTAs) was studied. The MTAs investigated here were linalool, nerol, geraniol, citronellol, and ${\alpha}$-terpineol. The ranges of MTA concentrations in the koguma-soju made from the four sweet potato varieties were $14.0-16.6{\mu}g/L$ for nerol, $24.8-34.7{\mu}g/L$ for linalool, $32.8-38.5{\mu}g/L$ for geraniol, $37.8-54.2{\mu}g/L$ for citronellol, and $76.6-94.7{\mu}g/L$ for ${\alpha}$-terpineol. Geraniol, nerol, and linalool were found in lower concentrations, while ${\alpha}$-terpineol was present in a higher concentration compared to their average content in the imo-shochu, a distilled Japanese sweet potato-soju. The concentrations of citronellol in the koguma-soju and imo-shochu were similar. The flavor evaluation tests revealed that the koguma-soju produced from the Yeonmi variety had a leafy vegetable or a grass-like, sharp flavor, whereas the Jeungmi-soju was characterized by a fruity or a sulfur-like sharp taste. Floral, vanilla-like, and mild flavors were predominant in the Shincheonmi-soju, while the Shinyeulmi-soju had either a fruity, citrus-like flavor or a rubber-like, rough taste. This study demonstrates that koguma-soju made from different sweet potato varieties have unique characteristic flavors.