• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.10
• /
• pp.1715-1719
• /
• 2004

In order to help the preservation of the unshiu orange and pear, antimicrobial paper incorporating grapefruit seed extract and zeolite was applied to pack fruits. Unshiu orange was packed in a box (24${\times}$24${\times}$22 cm) attached with antimicrobial paper and then stored respectively at l$0^{\circ}C$. Pears were wrapped individually before storage at l$0^{\circ}C$. During the storage, weight loss, pH, total acidity, soluble solid content, microbial load and decay were measured as quality indices. Steady pH increase in unshiu orange was observed to slightly decrease total acidity during the storage with little difference between the packaging treatments. The microbial loads of total aerobic bacteria, and yeast/mold counts were suppressed during storage by the antimicrobial paper packaging, which also contributed to reducing the decayed unshiu orange. Limited reduction of total aerobic bacteria and yeast/mold counts was observed only for initial storage period for the pears wrapped with 9 and 12% antimicrobial agent-added papers. Antimicrobial paper was useful for the reduction of microbial load in unshiu orange and pear without other quality deterioration.

• Research in Plant Disease
• /
• v.17 no.1
• /
• pp.78-81
• /
• 2011

Soft rot caused by Rhizopus oryzae occurred on unshiu orange (Citrus unshiu Marc.) sampled from commercial markets in Jinju, Korea, 2010. The first symptom of soft rot on orange is a water-soaked appearance of the affected tissue. The infected parts later disintegrated into a mushy mass of disorganized cells followed by rapid softening of the diseased tissue. The lesion on orange was rapidly softened and rotted, then became brown or dark brown. Optimum temperature for mycelial growth of the causal fungus on potato dextrose agar was $30^{\circ}C$ and growth was still apparent at $37^{\circ}C$. Sporangiophores were $6{\sim}20\;{\mu}m$ in diameter. Sporangia were globose and $40{\sim}200\;{\mu}m$ in size. The color of sporangia was brownish-grey to blackish-grey at maturity. Sporangiospores were sub-globose, brownish- black streaked and $4{\sim}10\;{\mu}m$ in size. Columella were globose to sub-globose and $85{\sim}120\;{\mu}m$ in size. On the basis of mycological characteristics, pathogenicity test, and the ITS sequence analysis, the causal fungus was identified as Rhizopus oryzae. To our knowledge, this is the first report of soft rot caused by R. oryzae on unshiu orange in Korea.

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

• Korean Journal of Environmental Biology
• /
• v.30 no.2
• /
• pp.98-106
• /
• 2012

The chlorophyll fluorescence and photosynthetic $CO_2$ fixation capacity of leaves from three major crop trees found on Jeju Island, Camellia sinensis L., Camellia japonica L., and Citrus unshiu M., were analyzed. The photosynthetic $CO_2$ fixation rate of C. sinensis was similar to that of C. unshiu, and much higher than that of C. japonica which belongs to the same genus. Stomatal conductance in the three species was high at dawn and low during daytime. The intercellular $CO_2$ concentration of the three species was also high at dawn and decreased at midday. The transpiration rate showed an opposite trend from the intercellular $CO_2$ concentration. The photochemical efficiencies of PSII (Fv/Fm) in C. sinensis were slightly lower at midday compared to the level at dawn and/or dusk. The decline in Fv/Fm of C. sinensis at midday was much smaller than that of C. japonica. These results indicate that C. sinensis is better acclimated to high levels of radiation under natural conditions in late summer, although its PSII reaction center was inhibited by strong radiation. Of the chlorophyll fluorescence parameters in the species, the RC/CS decreased significantly while the ABS/RC, TRo/RC, ETo/RC, and DIo/RC increased significantly at midday in late summer. However, C. unshiu did not show significant changes in these values depending on the time of day. Among the three species, the daily $CO_2$ fixation rate in C. sinensis ($320.1mmol\;m^{-2}d^{-1}$) was the highest, followed by that of C. unshiu ($292.5mmol\;m^{-2}d^{-1}$) and C. japonica ($244.8mmol\;m^{-2}d^{-1}$). Thus, C. sinensis may be a valuable crop tree in terms of the uptake of $CO_2$ under natural field conditions.

• Food Science and Preservation
• /
• v.13 no.3
• /
• pp.273-278
• /
• 2006

In order to help the preservation of the cherry tomato and unshiu orange, antimicrobial paper incorporating grapefruit seed extract and zeolite was applied to the package. Cherry tomato and unshiu orange were packed in a box (38x25x20 cm) attached with antimicrobial paper and then stored respectively at $5^{\circ}C$. During the storage, weight loss, pH total acidity, soluble solid content microbial load and decay ratio were measured as quality indices. pH increase in cherry tomato was observed until 20 days, and decreased with litle difference between the packaging treatments thereafter pH and total acidity decrease in unshiu orange were shown till 30 days, and abrupt change was revealed by 40 days. This was due to physiological disorders. The microbial loads of total aerobic bacteria, and yeast/mold count were suppressed during storage by the box packaging incorporated with antimicrobial agents, which also contributed to reducing the decayed cherry tomato and unshiu orange. Antimicrobial paper was useful fur the reduction of microbial load in cherry tomato and unshiu orange pear without other quality deterioration.

• Applied Biological Chemistry
• /
• v.41 no.2
• /
• pp.141-146
• /
• 1998

In order to determine the optimmum harvest time of Citrus unshiu Marc. var. miyagawa and C. unshiu Marc. var. okitsu produced in Cheju, citrus fruits sampled at packing houses or harvested directly on citrus tree in south and north area of Cheju were analyzed. The fruits were grown in size till middle of October, and soluble solids were increased continuously after that. The fruits size were different by positional directions on the tree, the quality of citrus fruits in central southern positions on the tree was good for fresh fruit consumptions. Compared with only the quality of citrus fruits as a factor of soluble solids, total sugar, pH, and color index, the optimum harvest time were supposed to be reasonable at late of November for C. unshiu Marc. var. okitsu, and at early of December for C. unshiu Marc. var. miyagawa. The results obtained from citrus fruits sampled at packing houses were supposed to be not suitable for determing the optimum harvest time, because of storage after harvest at ordinary harvesting time.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.135.1-135
• /
• 2003

A technique for detection of Xanthomonas axonopodis pv. citri, a causal bacterium of canker on Unshiu orange fruits, was developed using bacteriophage. Procedure for the detection was designed on the basis of the previous reports that one group(CPI) of X. axonopodis pv. citri bacteriophage and corresponding two Iysotypes distributed in Korea. First, fruit surface was washed with sterile distilled water and pellet was obtained from centrifugation. The pellet was resuspended in Wakimoto's potato semi-synthetic broth medium and divided equally into two parts. One part was heated in boiling water to kill bacterial cells. Bacteriophages(CP$_1$) were respectively added into two parts and 0.1 ml from each part was mixed with soft agar medium. After incubation for 18 hrs at 25$^{\circ}C$, the causal bacterium of canker was determined based on plaques formed on the medium. This procedure can be effectively used for detection of living bacterial pathogen on fruit surfaces of Unshiu orange.

• Natural Product Sciences
• /
• v.26 no.2
• /
• pp.176-181
• /
• 2020

Two new compounds, 3-methyl-but-2-en-1-yl-1-O-β-xylopyranosyl-(1"→2')-O-β-glucopyranoside (1) and 1-O-β-glucopyranosyl-6-hydroxy-2-methyl-hep-2-enoic acid (2), along with sixteen known terpenoids were isolated from the peels of Citrus unshiu Markov. Their structures were elucidated based on extensive NMR analyses (¹H NMR, ¹³C NMR, DEPT, COSY, HMQC, and HMBC) and high-resolution mass spectrometry. In addition, all isolates (1 - 18) were tested their effects on nitric oxide (NO) production in RAW264.7 cells. Limonin (15) showed to inhibit LPS-induced NO production in a concentration-dependent manner without cytotoxicity.

• The Korea Journal of Herbology
• /
• v.23 no.4
• /
• pp.159-170
• /
• 2008

Objectives: This study was carried out to evaluate the quality of the peels of various Citrus species. Method: The contents of hesperidin from fruit peels used as Citri Pericarpium such as C. natsudaidai, C. grandis, C. unshiu, and C. sunki, were analyzed by HP-TLC, HPLC, and essential oils of those were analyzed by GC/MS. Results: HPLC analysis showed that the hesperidin from the peel of C. unshiu and C. reticulata was satisfied the standard of Korean Pharmacopoeia. The essential oil was analyzed by GC/MS. As a result, limonene, furfural, 5-methyl-2-furfural, linalool oxide(cis), linalool oxide(trans), terpinen-4-ol, $(-)-{\alpha}$-terpineol, germacrene D, 4-methyl-2,6-di-tert-butylphenol was detected in all 4 kinds of Citrus species. Conclusions: As a result of chemotaxonomical similarity analysis with essential oils, the peels of C. natsudaidai and C. grandis are closely related, while C. unshiu is distantly related to the others.

• Preventive Nutrition and Food Science
• /
• v.7 no.1
• /
• pp.5-11
• /
• 2002

The comparison of the volatile flavor components from Korean and Japanese Satsuma mandarin (C. unshiu Marcov. forma Miyagawa-wase) peel oils, isolated by cold-pressing, was performed by gas chromatography, mass-spectrometry and gas chromatography-olfactometry (GC-O). Eighty-five volatile components were identified in each oil by GC and GC-MS. Forty-three components were detected in each oil by GC-O. The total amount of monoterpene hydrocarbons was 95.88% (Korean mandarin) and 95.29% (Japanese mandarin). Limonene, ${\gamma}$-terpinene, myrcene and $\alpha$-pinene were the main components of the cold-pressed oils from the both samples. The volatile composition of the Japanese mandarin was characterized by a higher content of sesquiterpene hydrocarbons, especially bicyclogermacrene, $\alpha$-humullene and valencene. The volatile composition of two samples can easily be distinguished by the percentages of aldehydes, ketones and esters, which were found at higher levels in the Japanese mandarin. The sweet and fruity flavor was stronger in the Korean mandarin oil while herbaceous flavor was stronger in Japanese sample. From GC-O data it is suggested that the sweet and fruity flavor of the Korean mandarin resulted from terpinolene and linalool, and the herbaceous note of the Japanese mandarin from $\alpha$-humullene, nepal, ι-carvone and perill aldehyde.