• 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.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.10
• /
• pp.1593-1598
• /
• 2005

These studies were carried out to investigate the possibility for utilization of waste articles and the production of function characteristics Pork by feeding unshiu orange byproducts. The samples consisted of the pork not fed with unshiu orange byproduct (TP-0), the pork fed with 3$\%$ and 5$\%$ unshiu orange byproduct during growing and finishing period, respectively (TP-1), and the pork fed with 6$\%$ and 10$\%$ unshiu orange byproduct growing and finishing period, respectively (TP-2). The moisture, crude protein, crude fat and crude ash were not significantly different among samples. It was found that TP-1 had the highest calorie. The cholesterol content was lowest in TP-2 (p < 0.05). It was found that TP-2 had the lowest Na among minerals. Vitamin $B_{1}$ and $B_{2}$ were not significantly different among samples. The total amino acid contents of TP-0, TP-1 and TP-2 were 18.86$\%$, 20.03$\%$ and 20.44$\%$, respectively. Total free amino acid and saturated fatty acid vs. unsaturated fatty acid of Pork loins were not significantly different mong samples. The sensory scores were not influenced by feeding of unshiu orange byproduct.

• 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.

• The Plant Pathology Journal
• /
• v.19 no.4
• /
• pp.205-209
• /
• 2003

Dispersal of citrus bacterial canker caused by Xanthomonas axonopodis pv. citri on Unshiu orange was investigated in naturally infested nursery plot at Seogwipo in Jeju island, Korea. Based on phage detection, over 2% of the bacterial pathogen over-wintered in canker lesions and started to multiply in late May. However, symptoms were first observed 1 month after the phage detection. The disease dispersed non-directionally to nearby plants possibly because of indirect dissemination of the bacterium by rain splashes. The disease increased from late June to late August and decreased thereafter. Population of phage increased constantly, however, disease occurrence somewhat fluctuated due to environmental factors. Disease incidence and severity were correlated with rainfall with wind that occurred 14-32 days earlier from late May to late August.

• 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.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.120.3-121
• /
• 2003

Relative degree of resistance of citrus to Xanthomonas axonopodis pv. citri, the causal bacterium of canker, was investigated. Growth rate of a bacterium in leaf tissues after infiltration, disease incidence, and percent of lesion area were compared. By using growth rate[(GR=(At - A$\sub$t-1/)/A$\sub$t-1] host plants were differentiated into susceptible and resistant. Growth rates reached to peak at 40 hrs after inoculation and then declined. The growth rate in leaf tissues of a moderately susceptible cultivar, Citrus sinensis vu. Lane late(sweet orange), was the highest, and those of C. unshiu ${\times}$ C. sinensis(kiyomi), C. junos(yuzu), [(Citrus. unshiu x C. sinensis) x C. reticulata] (shiranuhi), and C. unshiu(satuma mandarin) were similar. This result indicates that the growth rate of the bacterium in leaf tissues can be effectively used for evaluation of disease resistance for citrus plants to X. axonopodis pv. citri. The disease on sweet orange occurred earlier than relatively resistant citrus plants tested. The percent of lesion area on leaf was also higher in sweet orange than those of satsuma mandarin, shiranuhi and kiyomi, and yuzu. The disease severity was highest on sweet orange and followed by kiyomi, shiranuhi, satsuma mandarin, and yuzu.

• Applied Biological Chemistry
• /
• v.34 no.1
• /
• pp.14-20
• /
• 1991

Changes in fruit quality and some components of Unshiu orange(Citrus Unshiu Marc. Hayashi) stored at $2^{\circ}C$ in air or a controlled atmosphere(CA, $O_2$ 10%, $CO_2$ 2%) for 111 days were studied. The incidence of rot fruits was higher in air(12.7%) than in CA condition(3.9%). The appearance of the fruits was better in CA condition than in air. There was no significant difference in the weight loss of whole fruits between both storage conditions. The ratio of the flesh weight In whole fruits under CA condition was slightly lower than those in air until 62 days of storage, while it showed no rapid decrease in the later period of storage. Under both storage conditions, the Brix in the flesh increased in the early Period of storage and then decreased slowly, while the free acid contents decreased gradually during storage. In comparison with the fruits stored in air, those under CA condition showed lower total sugar content. The sugar in the flesh of the fruits is composed of sucrose, fructose and glucose. The content of total sugar as well as each sugar showed no distinct difference under both storage conditions. In the flesh of the fruits, citric acid comprised about 90% of the organic acid and malic acid the second abundant acid. During storage, the contents of citric, malic and oxalic acid decreased. Significant difference in the decreasing rate of total organic acid between both stnrage conditions was not found. From the above results, it might be considered that CA could be applied lot the storage of Unshiu orange grown on Cheju

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

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.121.1-121
• /
• 2003

Dispersal of Xanthomonas axonopodis pv. citri, causing citrus bacterial canker disease on Unshiu orange was investigated at previously infested plots at Seogwipo in Jeju island of Korea. The bacterial pathogen overwintered in lesions started to multiply at tate May, and disease firstly observed one month after detection of phage from lesions. The disease gradually increased, however, it dispersed non-directionally to nearby plants from inoculum sources. Diseased plants were aggregated to form a cluster throughout the experiment. Population dynamics of phage on symtomless leaf surface and the disease severity were compared in the nursery, Increase of phage population on symptomless leaf surface preceded one month to that of the disease severity Population of phage increased constantly from late July to October, however, the disease severity decreased from late August to late October. It was assumed that the decrease of disease severity might be due to disease-induced defoliation.