• Korean journal of applied entomology
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• v.50 no.3
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• pp.203-208
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• 2011

This study was conducted to evaluate Geometridae (Lepidoptera) species as pests and the damage they cause in citrus orchards in Jeju, Korea. Seven geometridae species occurred in citrus orchards: Ascotis selenaria, Ectropis excellens, Menophra senilis, Biston panterinaria, Ourapteryx nivea, Odontopera arida and Hypomecis punctinalis. Among them, A. selenaria was most abundant, followed by E. excellens and M. senilis. Most Geometridae larvae fed on citrus leaves, but A. selenaria larvae ate fruits and leaves. Fruit damage of Citrus unshiu appeared as gnawed scars caused by young larvae feeding on fruit surface. Fruit damage on Shiranui fruits appeared as a wide hole or deep scars caused by feeding by mature larvae (6th instar). Citrus leaves damage due to Geometridae larvae was high during May to June. Fruit damage started in late June as the spring-shoots of citrus hardened and increased sharply in late July. In the field experiment, fruit damage in the late season reached 4.2% in both 2008 and 2009 and reached 5.2% in 2010. In citrus orchards, A. selenaria larvae started to appear in mid-May and their populations peaked in mid June, late July, and early to mid-September. Adult males of A. selenaria had a maximum peak in mid-May, and two other peaks in early to late July and late August to early September. A. selenaria male adults were collected in a pheromone traps constantly throughout Jeju Island.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.483-487
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• 2016

The damage of citrus fruits caused by Scirtothrips dorsalis Hood has being increased in Jeju, Korea. The seasonal abundance of S. dorsalis and its injury symptoms in citrus orchards have been studied since the endemic outbreak in Jeju, but studies for the occurrence pattern of S. dorsalis in citrus orchards influenced by adjacent primary hosts have not been fully conducted yet. We selected kiwi- and mango-citrus adjacent orchards to study the migration pattern of S. dorsalis toward to citrus orchards. Yellow-colored sticky traps were used for monitoring the seasonal abundance of S. dorsalis and their migration pattern in two orchards. In citrus orchards, also, we placed sticky traps at 0, 5, 10, 15 and 20 m apart from the border of kiwi orchard, and 0, 7 and 20 m apart from the border of mango orchard. The seasonal occurrence pattern of S. dorsalis caught on sticky traps were similar between two adjacent orchards. However, the abundances in kiwi or mango orchard was much higher than those of citrus. Also, it was found that densities, distribution and damage of S. dorsalis in citrus orchards depend highly on the distance from the border of kiwi and mango orchards. This result suggested that the primary hosts such as kiwi and mango plants influence the occurrence of S. dorsalis in adjacent citrus orchards. And this information may provide a basic direction for establishing the management strategy of S. dorsalis in citrus orchards.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.4
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• pp.462-469
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• 2009

This study was conducted to investigate total polyphenolic contents and reactive oxygen species (ROS) scavenging effects of extracts from peels of ten Jeju native citrus fruits according to the harvest from August 2006 to February 2007. Total polyphenolic contents from methanol extracts of citrus peel were the highest in Jigak (Citrus aurantium) and Hongkyool (C. tachibana) by over 200 mg% in the unmatured period, from the late August to the late September, and all the citrus peels mostly decreased while ripening. Scavenging effect of superoxide anion radical showed good correlation with total polyphenolic contents. The unmatured periods of Hongkyool and Jigak were the highest with more than 60%. Hydrogen peroxide scavenging activity was the highest in Sadoogam (C. pseudogulgul) at 73.8% in late August and the second highest activity was observed in Jigak at near 70%, and all the citrus peels decreased during ripening. Hydroxy radical scavenging activity were the highest among all the ROS scavenging activities, especially in the Jigak and Dangyooja (C. grandis) at 75.1% and 74.6%, respectively, and not much affected by increased maturity of the fruits. Nitric oxide radical scavenging activity was the highest in Bungkyool (C. platymama) at 58.4% in late February, and increased with fruit ripening. In this study, Jigak was generally the highest in the polyphenolic contents and ROS scavenging activities, so the further studies are needed for industrial applications.

• Korean journal of applied entomology
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• v.39 no.4
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• pp.267-274
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• 2000

As the pest of the citrus in Cheju, 69 insect species and 5 animal species were investigated during 1996 to 1998. Of these, Panonychus citri, Phyllocnistis citrella, Aphis citricola, Aphis gossypii and Frankliniella occidentalis are major pests. Especially, F. occidentalis and Peridroma saucia are very important species because of increasing damage. The number of pests species injuring leaf, branch, fruit and flower of the citrus are 36, 16, 41 and 2 species respectively. The rate of damaged fruits by pests is 20.5% in 1997 and 18.6% in 1998 and the rate of bad quality fruits is 6.4% and 6.7% respectively.

• Korean journal of food and cookery science
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• v.24 no.2
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• pp.174-181
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• 2008

The purpose of this study was to determine the optimal mixing conditions for different amounts of konjac(0.2, 0.3, 0.4, 0.5, 0.6%) and carrageenane(0.8, 1.0, 1.2, l.4, 1.6%) in the preparation of citrus jelly, using the central composite design. The results showed that the sensory and mechanical characteristics of the jelly increased with decreasing konjac and carrageenane contents. Overall optimal conditions that satisfied the rheology, appearance characteristics and sensory properties of the citrus jelly were 0.2% konjac, 1.2% carrageenane and 30minutes of heating time using citrus juice of $20^{\circ}C$Brix and 0.3% citric acid.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.66-71
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• 2010

Jinpi(Aurantii nobilis Pericarpium) is one of the most important material of oriental herbal medicine which is made from the peel of mandarin by washing with hot water and drying. Pesticides have necessarily used for mandarin cultivation according to their preharvest intervals (PHIs) but their maximum residue limits (MRLs) and PHIs for Jinpi are not established yet. This study is to know residue amount of organophosphorus insecticides in Jinpi and to establish the MRLs and PHIs for fenitrothion and phenthoate in Jinpi. Fenitrothion was sprayed once, twice and three times with 7 days interval before harvest. Its residue amount ranged from 0.14 to 1.17 mg/kg in mandarin, 0.59 to 4.02 mg/kg in its peel and 1.66 to 22.38 mg/kg in Jinpi. In case of phenthoate, it was sprayed with 10 days interval for 10 days before harvest. Its residue amounts in mandarin, its peel, and Jinpi ranged from 0.16 to 0.65, 0.69 to 2.41 and 1.69 to 11.3 mg/kg, repectively. Proposed MRLs of fenitrothion and phenthoate for Jinpi are suggested to 22.39 and 11.30 mg/kg, respectively. So we recommend PHIs of the pesticides that fenitrothion can be sprayed 3 times 7 days before harvest and in case of phenthoate, sprayed 3 times 10 days before harvest.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.635-641
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• 2003

A non-thermal pasteurization technology, high Pulsed Electric Field (PEF) has been thought to be a new alternative processing technology instead of heating. The objective of this study was to examine and compare the effect of PEF and High Temperature Short Time (HTST) treatments on the physicochemical, microbiological and sensory characteristics of citrus juices. Total sugar and titratable acidity values of fresh citrus juice and two treatments were not significantly different each other at p<0.05. The concentration of vitamin C in fresh citrus juice $(31.2{\pm}0.59\;mg%)$ was not significantly different with the value of PEF treatment $(29.4{\pm}0.75\;mg%)$ but was significantly higher than the value of HTST treatment $(27.4{\pm}0.75\;mg%)$. The color values (L, a, and b) in PEF treatment were significantly lower than the fresh citrus juice, but were higher than the values of HTST treatment. Both total bacterial cell counts $(6.65\;{\pm}\;0.08\;log_{10}(cfu/mL))$ and yeast counts $(7.79{\pm}0.07\;log_{10}(cfu/mL))$ in fresh citrus juice were significantly reduced by PEF $(1.39{\pm}0.14,\;2.42{\pm}0.1\;log_{10}(cfu/mL))$ as well as HTST treatment (0, 0). PE activity of fresh citrus juice $(1.3{\pm}0.12\;units/mL)$ was significantly reduced by PEF treatment $(0.11{\pm}0.01\;units/mL)$ and was totally inactivated by HTST treatment. Sensory evaluation scores in flavor, taste and overall acceptability between the fresh and PEF treated citrus juices $(7.2{\sim}7.5)$ were not significantly different but the values of HTST treatment $(5.1{\sim}5.8)$ were lower than others. Consequently, PEF treatment is thought to be a good alternative pasteurization method for fresh citrus juice to HTST treatment due to its strong pasteurization effect, reduced destruction of nutrients and good sensory characteristics.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.521-524
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• 2006

본 연구에서는 농업폐기물인 감귤박의 효율적인 재활용 방안으로 고부가가치 제품인 활성탄을 제조하여 이용하는 가능성에 대하여 조사한 결과, 감귤박 폐액으로부터 건조한 시료의 조성은 대부분이 탄수화물로 구성되어 있으며, 또한 이는 미생물, 농약 및 중금속에 오염되지 않은 순수한 천연 재료로 구성되어 있음을 알 수 있었다. 또한 탄화공정 및 활성화공정을 통해 제조된 활성탄의 요오드 흡착능이 KS 규격 중 1급(활성탄 1,100 mg/g 이상)보다 높은 값으로 나타나 공업용 활성탄으로의 활용이 가능할 것으로 사료된다.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.781-784
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• 2011

본 연구의 목적은 농촌진흥청 국립원예특작과학원 감귤시험장에서 개발된 감귤신품종인 하례조생의 개발의 기술가치를 평가하는 것이다. 이는 농업 R&D사업의 효율성과 실용성 제고를 위하여 이용될 수 있을 것이다. 분석결과에 따르면, 감귤신품종 개발에 따른 기술가치평가액은 할인율 수준에 따라 최소 638.7억 원 (할인율 10%)에서 최대 1,088.7억 원(할인율 6%), 평균 829.17억 원(할인율 8%)으로 추정되고, 내부수익율 IRR의 값은 가정했던 할인율(6%~10%)보다 훨씬 크고, 순현재가치(NPV)는 영보다 훨씬 크며, B/C 비율도 60 이상으로 나타나 신품종개발사업의 경제적 타당성은 있는 것으로 판단된다.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1994.07a
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• pp.13-14
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• 1994

제주지역에서 생산되는 대표적인 품종인 궁천조생과 흥진조생에 대한 품질에 관여하는 물리.화학적인 특성을 분석하였고 과일의 크기, 색깔, 생산지역에 따른 감귤의 맛등에 대한 관능검사를 실시하였다. 수확적기에 수확한 조생온주으 가용성고형물은 10.7, 11.0 였으며 산함량은 1.04%, 비타민 C함량은 41.19-44.94mg/100g였다. 당은 절반이 자당하이였고, 포도당과 과당이 각각 1/4씩 함유하고 있었다. 과일 크기에 따라 과중, 껍질두께, 가용성고용물, pH, 산함량, 산비는 각각 직선적인 상관관계를 가지고 있었으며, 경도와 과육율과의 유의성은 없었다. 관능검사 결과 중간정도의 크기의 감귤을 선호하며. 껍질의 색깔은 진한 홍등색일수록 선호하고 있음을 알 수 있었다. 또한 같은 품종이라고 할지라도 재배적지에서 생산된 감귤일수록 선호도가 높아 직선적인 유의성을 보였으며, 과즙의 경우 당산비가 높을수록 성호하여 고품질 감귤생산을 위한 노력이 필요한 것으로 여겨졌다.로 여겨졌다.