• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1275-1279
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• 2004

Citron peel oil was extracted from citron (Citrus funas) fruit by steam distillation, and was used as starting material for microbial conversion to synthesize attractive flavor compounds by using Enterobacter agglomerans 6L. E. agglomerans was isolated from citron peel and was able to metabolize the citron peel oil and grew well ($A_{600}:\;3.0$) on the citron peel oil as the sole carbon source. Multiple terpene metabolites were produced by E. agglomerans 6L on M9 salt media with citron oil vapor. The identified bioconversion products from the citron peel oil included trans-2-decenal, octanol, $\delta$­valerolactone, $\gamma$-valerolactone, cryptone, hydroxycitronellol, cuminol, and $\gamma$-dodecalactone.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.357-362
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• 2006

We assessed various antioxidant activities, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis 3-ethylbenz-thiazoline-6-sulfonic acid (ABTS) radical, and reactive oxygen species (ROS) radical scavenging effect, along with antioxidant capacity, of soybean oil with added Citrus species peel extracts (CPEs). These extract oils showed higher radical scavenging effects than grape fruit seed extract, the natural antioxidant agent, did. When CPEs were added to soybean oil, they showed peroxide value (POV) and acid value (AV) increasing inhibition effects. Furthermore, none of the CPEs showed any cytotoxicity over the tested concentration range of 0.01-100 ppm. The major flavonoid contents of Citrus junos, as determined by HPLC, were naringin ($7.5\;{\mu}g/mg$) and neohesperidin ($7.5\;{\mu}g/mg$), and those of Citrus unshiu were narirutin ($3.13\;{\mu}g/mg$) and hesperidin ($1.97\;{\mu}g/mg$). However, the aglycone form was not found. This study showed that CPEs might be a potent source of natural antioxidant, without any toxic effects.

• The Plant Pathology Journal
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• v.15 no.6
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• pp.335-339
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• 1999

Citrus tristeza virus(CTV), an aphid-borne closterovirus, is one of the most destructive pathogens of citrus. It has caused rapid decline in growth, stem pitting and death in citrus trees. A reverse transcriptase polymerase chain reaction (RT-PCR) assay was developed for detection of CTV and investigation of the CTV infection status of citrus and its related cultivars in Cheju island. For RT-PCR based CTV detection, primers were designed to amplify 670bp of coat protein gene. A screening test for CTV in citrus cultivars was conducted from March to July in 1999. Seventy individual citrus trees representing 9 species of 3 genera were tested. The infection rates of CTV for leaves from the years or older trees of late maturing citrus varieties such as Yuzu (C. junos Sieb. ex Tanaka), Navel orange (C.sinensis Osbeck), Kiyomitanger (C. unshiu x C. sinensis), and Shiranuhi ((C. unshiu x C. sinensis) x C. reticulata) were 100%, 80%, 60%, and 60% respectively. The CTV infection rates in Early satsuma mandarins such as 'Miyagawa Early' Satsuma mandarins (C. unshiu Marc. var. Miyagawa) and 'Okitsu Early' Satsuma mandarins (C. unshiu Marc. var. Okitsu) were 100%, and 60%, respectively. CTV was not detected in Cheju native Dangyooja (C. unshiu Marc. var. Osbeck), Trifoliate orange (Poncirus trifoliata) and Kumquat (Fortunella margarita Swingle). In conclusion, RT-PCR assay can be successfully applied to the detection of CTV in citrus trees.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.1
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• pp.58-63
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• 2007

To develop a new type of surimi with added citrus fruits, we examined the colors, textural properties and sensory evaluations of surimi after production. In the folding test, all samples had good flexibility, which suggested that addition of citrus fruits did not influence the flexibility of surimi. The pH in surimi samples was, in increasing order: lemon(Citrus limon), citron(Citrus junos), tangerine(Citrus unshiu), cumquet(Fortunella japonica var. margarita), and control. The pHs of each citrus fruits and the surimi with added citrus fruits were similar. Lightness increased in the following order: lemon, cumquet, control, citron, and tangerine surimi. Redness was high in the following order: tangerine, cumquet, control, citron, and lemon surimi. Yellowness increased in the following order: tangerine, cumquet, citron, lemon, and control surimi. There were no significant differences between lemon and control surimi. The hardness of surimi was highest in lemon, followed by citron, tangerine, cumquet, and control surimi. Although control surimi was the lowest, there were no significant differences among the samples. In terms of springness, it increased in the following order: tangerine, citron, control, lemon, and cumquet, but there were no significant differences among the samples. In sensory evaluation, overall acceptability decreased in the following order: cumquet, tangerine, control, citron, and lemon. Surimi containing cumquet got the best score in colors, textural properties, and taste except flavor. All samples got positive results in sensory ova luations, except for textural properties and taste of lemon and citron. Here, we confirm that surimi can be made with added citrus fruits, although we should examine in detail the quantities of added lemon and citron in a later study.

• Korean Journal of Plant Resources
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• v.10 no.3
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• pp.213-220
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• 1997

The present study has been undertaken to characterize availability of citrus as a medicinal plant with antineoplastic property. The crude extracts from 40 species of fruits with 12 species of the local Citrus in Cheju island were evaluated on their potential activities against mouse P388 lymphocytic leukaemia in vitro. The percent cytotoxicity varied from 25.40 to 97.94% at a concentration of $100{\mu}g/mL$. Among 40 spp., 8 species showed high toxicity more than 90% against P388 cells and Cheongkyool(C. nippokoreana) exhibited the most cytotoxicity as 97.94%($IC_{50}=20.2{\mu}g/mL$). Nine varieties of C. junos were showed insiginicant cytotoxicity. In trifoliate orange, immature fruit was stronger than mature and peel extract showed higher cytotoxicity($IC_{50}=18{\mu}g/mL$) than the other tissues. Hexane fraction from methanol(MeOH) extract of trifoliate orange showed highly significant inhibition of cell growth($IC_{50}=3.9{\mu}g/mL$). In addition, its cytotoxicity increased remarkably from 3.95 to $0.40{\mu}g/mL$ as exposure time legthened. Cytotoxic activities of crude extracts were decreased considerably during a six months storage period. It was apparent that there is considerable variation in cytotoxicity, depending upon species, maturity and storage time of extracts. There was no meaningful cytotoxic difference between archicitrus and metacitrus in the genus Citrus.

• Korean journal of applied entomology
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• v.40 no.1
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• pp.77-82
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• 2001

Flying behavior during nighttime and control methods of fruit sucking pests were investigated in yuzu (Citrus junos) groves at Koheung area from August to November in 1999. Among the 3 kind of bulbs with different color (white, blue and yellow), white bulb attracted the most number of fruit sucking pests . The 93 percent of the moths was attracted from sunset to 24 o\`clock. Main flying time of hemipteriods in early, mid, and late October were from 22 to 04 o\`clock, sunset to 02 o\`clock and sunset to 24 o\`clock, respectively. Their flying time become earlier as the night temperature declines. For control of fruit sucking pests, attraction liquid traps, light traps (100 W) and illumination light bulb were set up in the yuzu groves (1,000 $\m^2$) from the 1 st October to the 3rd November. Attraction liquid was composed of a raw rice wine 2,000 ml+black sugar 100 g+vinegar 100 ml. When established at 3 sites per 1,000 $\m^2$ orchard, attraction liquid trap reduced the number of sucking spots on yuzu fruit to 64% and its attracting effect maintained for 3 weeks after setting-up. Three light traps per 1,000 m2 which turned on from sunset to 02 o\`clock reduced the number of sucking spots by 60% .

• Journal of Life Science
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• v.18 no.10
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• pp.1435-1441
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• 2008

In this study, anti-cancer activities of peel of Citrus junos (CJP) and Poncirus trifoliata (PTP) on MCF-7 breast cancer cells, and anti-proliferative effects of cancer cells induced by environmental hormones were investigated. The ethanol extracts of CJP and PTP inhibited cancer cell growth and induced apoptosis at the concentration over 300 mg/ml treatment for 72 hr. Morphological change of MCF-7 breast cancer cells were observed treated with the CJP and PTP of 500 mg/ml concentration for 72 hr, and apoptosis was induced by activation of caspase-3. The proliferation of MCF-7 breast cancer cells was decreased in a dose-dependent manner treated with various concentration of CJP and PTP, when compared with the control at 300 mg/ml, the proliferation of the MCF-7 breast cancer cells of both extracts was decreased over 70% and 80%, respectively.

• Journal of Food Hygiene and Safety
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• v.20 no.4
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• pp.237-243
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• 2005

Methanol, ether, ethylacetate and water extracts from flesh and peel of yuna (Citrus junos) were investigated to analyze their ability of electron donating, nitrite scavenging and nitrosodimethylamine (NDMA) formation in model system. The electron donating ability of ynza flesh extract, when it added at 10 mg/ml or over, were more an $50\%$, except ether extract. The high electron donating ability ($99.2{\pm}0.37\%$) was observed in the methanol extract and its effect was similar to BHA and ascorbic acid, when 40 mg/ml of methanol extract was added in reaction solution. Nitrite scavenging ability of all extracts ken yuza was increased in proportion to sample concentration and more than $40\%$ when 1 mg/ml sample was added, under pH 1.2. Also nitrite scavenging ability was higher in peel extracts than flesh extracts of yuza. Inhibition ratio of NDMA formation from flesh methanol extract of yuza was $31.7{\pm}1.25\%$, when 40 mg/ml added under pH 1.2. In all samples, inhibition effects were lower than $20\%$, at pH 4.2 and 6.0.

• Journal of Food Hygiene and Safety
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• v.19 no.3
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• pp.126-131
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• 2004

This study was conducted to investigate of inhibition activity of yuza (Citrus junos) extracts and juice on nitrite scavenging and N-nitrosodimethylamine (NDMA) formation in model system. Yuza juice was separated into organic acid, ascorbate and phenolic portion using sep-pak $C_{18}$ cartridge, respectively. Nitrite scavenging activity and inhibition of NDMA formation from yuza extract has shown higher inhibition with pH of reaction condition lower and amount of added sample more. And peel extract of yuza was higher than those of flesh extract. Nitrite scavenging activity was excellent juice portion rather that 3 portions. Of the 3 portions, it activity was the highest in the organic acid portion, and decreased in the following order; phenolic acid, ascorbate portion. Therefore, organic acid of yuza was suggested to expect effective ihhibitor of NDMA formation.

• Food Science and Preservation
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• v.13 no.2
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• pp.204-210
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• 2006

To accept basic data of utilizing of citron (Citrus junos) as a raw material of industrial produce, major chemical components of citron were investigated. Weight ration of poet flesh md seed of citron were 44.7, 42.9 and 12.4%, respectively. Comparing proximate composition of peel and flesh of citron, peel showed higher in crude protein crude fat and crude ash than flesh but lower in moisture, carbohydrate and soluble solid. The major free sugars of citron were fructose, glucose and sucrose. Peel contained higher in sucrose than flesh, but lower in fructose and glucose. The content of K md P were 309 and 15.9 mg% in peel and 175 and 22.4 mg% in fresh, respectively. The main organic acids of citron were citrate, malate and oxalate. Total organic acid content of flesh (6.6%) was higher than that of peel (4.6%). Total amino acid content of peel and flesh were 671.9 and 315.7 mg%, respectively. Free amino acid content of peel and flesh were 324.3 and 280.7 mg%, respectively, and the major ones were proline, serine, glutamic acid, aspartic acid, and histidine. Total 49 volatile compounds were detected and 26 of these ones were identified in cion. The major volatile component of citron was limonene, which consists of 80% among the total volatiles in peel by all extract methods.