• Applied Biological Chemistry
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• v.37 no.3
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• pp.161-167
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• 1994

Soluble solids $(^{\circ}Brix)$, acid content and vitamin C content of Citrus miyakawa unshiu and C. okitsu unshiu juice harvested middle of November 1993 in Seuho-Dong and Topyung-Dong, Seogwipo-si, south area of Cheju were $10.7{\sim}11.0$, 1.04% and $41.19{\sim}44.94\;mg/100\;g$ juice, respectively. Carbohydrate was consisted of about 1/2 sucrose, 1/4 glucose, and 1/4 fructose. Fruit weight, peel thickness, soluble solids, pH, acid content and Brix/Acid ratio had a good correlation in linear function with increasing fruit size, respectively. However, hardness and edible part ratio were not showed correlation with increasing fruit size. Middle size of citrus fruit was favorable to panelists, and the citrus peel color of red yellow was more favorable than pale yellow color in sensory evaluation. Sensory evaluation score showed a linear correlation among citrus fruits of C. okitsu unshiu produced in Namwon-ri, Seuho-Dong, Seogwipo-si, south area of Cheju, and that of Chochun-ri, Ara-Dong, Cheju-si, north area of Cheju, and the score was higher according to citrus fruit produced in optimum cultivation area. With increasing Brix/Acid ratio of citrus juice, high sensory evaluation score was gained in panelists. These data obtained are supposed to be applied to the quality evaluation of Citrus unshiu produced in Cheju.

• Food Science and Preservation
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• v.3 no.2
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• pp.105-111
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• 1996

The conditions of cold stroage of Citrus unshiu Marc. var. okitsu produced in Cheju were investigated. The changes of peel moisture contents soluble solids, total sugar, vitamin C and density were slightly occured, and decay ratio was below 20% on keeping freshness relatively till late of March during cold storage. After thats decayed citrus fruits were increased gradually mainly from cold injury with lower temperature and high humidity. The loss of fruit weight, decrease of fruit hardness, and decrease of acid content were occured gradually during cold stroage. Because of the difficulty of long term storage for Citrus unshiu, the conditions and periods of cold storage would be determined after considering the physicochemical properties of fruits every year.

• Journal of Preventive Medicine and Public Health
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• v.42 no.1
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• pp.67-72
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• 2009

Objectives : Using the population-based cancer registry in Jejudo, we found that Jejudo had lower incidence in stomach cancer than other regions in Korea. The aim of this study was to evaluate reasons for this difference. Methods : Citrus is the leading agricultural production in Jejudo, suggesting that lower cancer incidence in Jejudo could be explained by citrus fruit intake. We evaluated this hypothesis with quantitative systematic review(QSR). Results : Stomach cancer incidence was significantly lower, with a summary odds ratio(SOR) after QSR of 0.72 [95% CI=0.64-0.81]. In addition, the SOR of pancreatic cancer tended to be lower at 0.83 [95% CI=0.70-0.98]. The SOR of prostate cancer was slightly higher at 1.03 [0.89-1.19]. Conclusions : Quantitative systematic reviews for the effect of citrus fruit intake on cancer occurrence suggested that lower cancer incidence in Jejudo could be explained by intake of citrus fruits.

• Mycobiology
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• v.28 no.3
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• pp.158-162
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• 2000

Twenty-three isolates of Fusarium spp. were obtained from decayed citrus fruits in the fields and storages in 1998-1999. Of them, six and five isolates belonged to F. proliferatum and F. moniliforme, respectively, which were the most common. F. solani and F. sambucinum had each two isolates, F. equiseti had one isolate and seven isolates were unidentified. They produced symptoms of two types in pathogenicity test: those with leathery, beige to light or dark brown, and sunken lesions without surface mycelium (type-1) and those with lesions covered with white, beige or pink surface mycelium (type-2). Four of six isolates identified to F. proliferatum and two unidentified isolates produced type-1 lesions, and all isolates identified to F. moniliforme, F. solani, F. sambucinum, F. equiseti and five unidentified isolates produced type-2 lesions.

• Korean Journal of Pharmacognosy
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• v.49 no.2
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• pp.113-123
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• 2018

The application of 112 samples of Citrus fruit peel, which is commonly cultivated in Korea as crude drug, has been limited due to the absence of criteria concerning chemical constituents and application of itself. In the context, this study is on the analysis of 11 flavonoid compounds. As a result, the flavonoid pattern could be classified into 5 groups. Furthermore, by utilizing this HPLC data, this study could provide a basis for fruit peel applications of not only Citrus unshiu, but also its cultivars, hybrids and some of Citrus plants which has been cultivated in Jeju Island for a long time. Moondan could be used for the same purposes as Chinese Huajuhong, and Poncirus trifoliata of Korean Jisil origin are effective enough, in terms of ingredients and function, compared with C. aurantium. Based on the content and composition of the PMF region in this study, C. unshiu and C. reticulata, as Tanaka System shows, should be considered as different hortcultural speicies. Also, Jikak, which is known as 'sour orange' until now, is confirmed as Chosen-daidai, C. tenuissima, that was reported by Tanaka in 1970, and this C. tenuissima could be used for the same purposes as sour orange.

• Mycobiology
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• v.49 no.3
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• pp.267-274
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• 2021

Two Diaporthe species isolated from fruit of Citrus sinensis in China were characterized based on morphology and multilocus phylogeny of ITS, tef1, and tub2 gene sequences. The phylogeny indicated that the two species match Diaporthe taoicola and D. siamensis. A critical examination of phenotypic characteristics confirmed the phylogenetic results. Diaporthe taoicola was morphologically characterized by producing Alpha conidia with tapering toward both ends. Meanwhile, D. siamensis produced cylindrical or ellipsoidal Alpha conidia with two oil drops. Pathogenicity tests revealed that both species were pathogenic to fruit of C. sinensis. To our knowledge, the two species were firstly reported on Citrus sinensis in China.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.312-316
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• 2006

Crude extract of young dangyuja (Citrus grandis Osbeck) fruit was investigated for its antioxidant activity as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. Among the samples, including 4 Citrus species and various solvent-extracted-fractions of young dangyuja fruit, the water-extracted fraction (WF) and butanol-extracted fraction (BF) showed the greatest DPPH free radical scavenging activity. WF and BF were further examined for their antioxidant activities by three different in vitro assays. The cell viability tests using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay showed that both fractions significantly reduced $H_2O_2$-induced cytotoxicity in HepG2 cells dose-dependently. Generation of the reactive oxygen species (ROS) was also reduced in cells pretreated with both fractions. In addition, BF showed a higher level of lipid peroxidation inhibitory capacity than WF in $H_2O_2$-treated HepG2 cells. Taken together, these results indicate that young dangyuja fruit can be used as an easily accessible source of natural antioxidants.

• The Plant Pathology Journal
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• v.36 no.5
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• pp.509-514
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• 2020

Satsuma dwarf virus (SDV) seriously damages citrus production by reducing the quality and yield of fruit. To avoid contamination with SDV, mother trees are checked to be SDV-free in advance of nursery tree distribution. In this study, we compared an immunochromatographic assay (ICA) kit with double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for large-scale diagnosis of SDV in orchardgrown trees in Shizuoka Prefecture, Japan. The two methods gave conflicting results for 11 of 1,705 samples, all of which were negative by DAS-ELISA but positive by ICA. The samples scored as positive by either DAS-ELISA or ICA were analyzed by reverse transcription polymerase chain reaction and all were confirmed to be positive. These results validate the use of ICA as a screening method for large-scale diagnosis. Strain discrimination revealed that 16 of 22 isolates belonged to SDV, while citrus mosaic virus (CiMV) infection only and co-infection (SDV and CiMV) were in a minority.

• Korean Journal of Plant Resources
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• v.8 no.3
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• pp.265-274
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• 1995

Characteristics of vegetative spur leaf, spur bud, fruiting supr leaf and flowering in relation to canopy position was investigated on order to promote better spur bud and flower bud differentiation on Citrus junos. There was no difference in vegetative spur leaf characteristics among directions. Vegetative spur leaf number and leaf area showed no difference between top and bottom position. There was no difference in spur bud size among directions, but spur bud at top was larger than that at bottom. Specific leaf weight of vegetative spur was mostly influenced by light interception, and leaf dry weight per spur average leaf dry weight, spur bud length and diameter had also a very high correlation with light interception rate. Shading and GA treatment in spur bud and flower bud differentiation was ineffective than natural light. Fruit thinning enhanced fruit quality as well as flower bud differentiation through an increase of leaf number per fruit, over 40 in Citrus junos.

• Korean Journal of Environmental Agriculture
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• v.41 no.4
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• pp.318-327
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• 2022

BACKGROUND: The mean annual temperature of the Korean Peninsula will continue to rise due to global warming. 'Shiranuhi' mandarin-a late-harvest cultivar-is primarily cultivated in plastic greenhouses where high temperatures cannot be directly avoided. Therefore, growth and fruit quality changes under elevated temperatures must be investigated. METHODS AND RESULTS: Elevated temperatures were divided into three groups [2℃ (T-I), 4℃ (T-II), and 6℃ (T-III) above the ambient temperature] during the 2019-2020 season. Mean temperatures were 17.1℃, 18.6℃, and 20.2℃ in T-I, T-II, and T-III, respectively. The bud bursts in T-II and T-III were earlier than that in T-I at 7 days and 11 days, respectibely. And the full blooms in T-II and T-III were earlier than that in T-I at 11 days and 23 days, respectively. Fruit size significantly increased with increased temperature. The citrus color index in the coloring phase markedly differed across treatments. Further, total soluble solid and acid contents markedly changed with temperature rise but the sugar-to-acid ratio did not. Sucrose content tended to decrease with increase in temperature, but citric acid content remained unaffected. CONCLUSION(S): Elevated temperature accelerated plant growth and development but delayed rind color development in 'Shiranuhi' mandarin. Therefore, rise in ambient temperature by >4.6℃ may negatively affect yield and fruit quality.