• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.306-312
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• 1998

Free sugar, organic acid, naringin, hesperidin and inorganic elements change of six varities of Cheju citrus fruits; Citrus natsudaidai, C. grandis, C. platymamma., C. sudachi, C. aurantiun and C. unshiu Marc. var. miyagawa by harvest date were investigated. Changes in free sugar of citrus fruits on the different harvesting stages and varieties showed a little differencies. The content of sucrose, glucose and maltose in citrus juice were $44.9{\sim}66.0%,\;15.7{\sim}25.7%\;and\;17.5{\sim}30.1%$, respectively. As the fruits were matured, free sugar was increased, but organic acid was decreased gradually. The major organic acids from the fruit juice were citric acid, malic acid and oxalic acid. Citric acid content exceeded 90%, oxalic acid ranged less than 3.58% and malic acid ranged $0.98{\sim}9.45%$ in total organic acids. Both naringin and hesperidin content showed markedly high in immature fruits, and in rind compare to fruit juice. Naringin and hesperidin content decreased as peel coloration progressed. It was estimated that fully matured fruits would be useful for making processed products, which lead to less turbity and less bitterness.

• Horticultural Science & Technology
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• v.30 no.2
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• pp.214-219
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• 2012

This study aimed to develop a new type of functional citrus beverage (Citurs-F) containing flavonoids extracted from the young fruits of satsuma mandarin ($Citrus$ $unshiu$) and matured fruits of Jeju native dangyooja ($C.$ $grandis$). We made beverages that contained 30% of satsuma mandarin extract with different percentages of concentrated dangyooja-derived flavonoid extracts. In sensory evalution, the highest response indices of color, taste and aroma were from the beverages based on the 30% young fruit extracts plus 15% (Citrus-F-15) and 20% (Citrus-F-20) flavonoids extract from the dangyooja using the KILO prep. In the changes of body weight after oral administration of the Citrus-F, the rat group with HF diet plus the Citrus-F decreased the body weight compared to the rat group fed only HF diet. This effect was to be continued for 9 weeks until the end of experiment. In the lipid content in blood, the rat group with oral administration of citrus extractions merely tended to resolve it in serum test. However, all the 0.1% Citrus-F-15 and Citrus-F-20 treated rat groups from the beginning or after 5 weeks appeared the lowest lipid contents in the blood. In the cholesterol contents, the rat group feeding the KILO-prep's extraction from the beginning weren't significantly recognized them in the group but the rat group feeding 0.1% Citrus-F-15 acted to reduce in the cholesterol contents from 5 weeks. The results indicated that the Citrus-F-15 with rich flavonoids might be main source alleviating the vascular diseases and obesity in human diet.

• Applied Biological Chemistry
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• v.9
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• pp.97-104
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• 1968

A survey of the free amino acids and free sugars in the juice of fourteen citrus varieties was made by means of paper chromatography and the pectin content in the rind was detected The results of the survey are summarized as follows. 1) Sixteen aminoacids detecteu in fourteen varieties under the condition of this study were distributed with. different frequency as follow. Proline, gamma-amino-butyric acid, alanine, valine, serine, glutamic acid, aspartic acid (in 14 varieties), lysine(12), leucine threonine(11), isoleucine(10), arginine(9), glycine(6) ${\beta}-alanine$(4) asparagine(3) unknown(2). 2) Proline, gamma-amino-butyric acid were mostly abundant in all varieties and alanine was next in the amount. 3) The varieties in the decreasing order of number of amino acids container were C. grandis madow C. leiocarpa (14 acids), C. sulcata, C. hassaku. native citron, Fortunella japonica(13) C. grandis heiko, C. Tamurana iyo, C. nobilis(12) C. reticulata C. junos(11) C. natsudaidai(10) C. miyakawa unshiu, C. ohali unshiu(9). 4) The varieties which appear to contain all essential amino acids(6 acids)detected were C. grandis madow C. grandis heiko, C. sulcata, C. Tamurana iyo, C. hassaku and native citron, and C. natsudaidai, C. unshiu were the least (1-3 acids). 5) Glucose fructose, sucrose and maltose were detected in all varieties. 6) The pectin content in the rind ranged from 8.64% F.W.(C. junos) up to 17.0% for C, grandis madow and the mean was $11.63{\pm}2.69%$.

• 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.

• Culinary science and hospitality research
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• v.23 no.8
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• pp.83-89
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• 2017

Dangyuja (Citrus gradis), a native citrus fruit of Jeju Island, has sour and bitter tastes. Dangyuja is rich in dietary fiber and enhance antioxidant activity. In this study, sponge cake was prepared by adding Dangyuja peel powder, and its quality characteristics were investigated. The freeze-dried Dangyuja peel powder was added to sponge cakes at a content of 0% (control), 2% (DP2), 4% (DP4), 6% (DP6) and 8% (DP8) of wheat flour weight. The specific gravity and baking loss of dough tended to increase with the amount of Dangyuja peel powder added, but the pH value as well as volume index of the cake were decreased. The symmetry index of cake tended to increase. Color values of sponge cake crust showed no significant difference, but L value and a value of crumb were decreased. The hardness and chewiness were increased with adding Dangyuja peel powder. Springiness was the highest at DP2 (91.79%). Cohesiveness did not showed significant difference among all samples. In a consumer preference test, cake groups with Dangyuja peel powder was higher than DP0 in color, texture, and overall acceptability. From these results, it was concluded that Dangyuja affects characteristics of sponge cakes. When making Dangyuja peel sponge cakes, it is suitable for adding 4% Dangyuja peel powder.

• Research in Plant Disease
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• v.30 no.1
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• pp.78-81
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• 2024

This study aims to isolate and identify the fungal pathogen responsible for gummosis disease affecting Thanh Tra pomelo in Vietnam. Through molecular identification utilizing primer pairs ITS5 and ITS4, the analysis pinpointed Lasiodiplodia theobromae as the specific fungal pathogen. Notably, the fungal colonies exhibited vigorous growth on potato dextrose agar. Initially, these colonies appeared whitish-grey, transforming into a black-grey hue within 5-7 days at a temperature of 30℃. According to previous reports, Phytophthora spp. was the most common pathogenic genus causing gummosis on Thanh Tra pomelo in Vietnam. To our knowledge, this is the first report on L. theobromae causing gummosis on Thanh Tra pomelo in Vietnam.

• International Journal of Industrial Entomology and Biomaterials
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• v.47 no.1
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• pp.12-24
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• 2023

Sitophilus oryzae L. (Rice Weevil) is a stored pest of rice that causes extensive loss throughout the world. We tested the leaf powders of 12 plant species viz., Chrysanthemum sp., Cinnamomum zeylanicum, Citrus grandis, Citrus limon, Gliricidia sepium, Gymnema sylvestre, Hemigraphis colorata, Michelia champaca, Moringa oleifera, Murraya koenigii, Polyalthia longifolia, and Sauropus androgynus at dosages of 1.00, 1.50, 2.00 and 3.00g against the adult rice weevil and mortality was recorded at 1, 2, 3, 5, 7, 12 and 2l days after treatment (DAT) by direct contact toxicity for their adulticidal effect. We observed 100 percent adult mortality in C. zevlanicum and M. koenigii among the tested leaf powders. In addition, the first-time tested H. colorata and S. androgynus also caused high mortality compared to other plants. All the plant powders caused moderate to high adult mortality. Hence, these plants could be effective botanical insecticides against S. oryzae as they comprise a potential source of bioactive chemicals and are generally free from toxicants. Applications of these natural derivatives in S. oryzae control could reduce the cost of control methods and storage of rice contamination. Therefore, the present study indicates that some plant extracts can be used as an alternative to toxic synthetic chemicals in the management of rice weevils.

• Journal of Nutrition and Health
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• v.42 no.3
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• pp.278-290
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• 2009

This study aims to evaluate the changes of flavonoid contents and antioxidants activity of Jeju native citrus fruits juice according to the harvest date. Flavonoids such as quercatagetin, narirutin, hesperidin and neohesperidin were contained most plentifully in the juice of Jigak (Citrus aur-antium) by 573.73 mg/100 mL, Sadoogam (C. pseudogulgul) by 393.99 mg /100 mL, Soyooja by 29.63 mg/100 mL and Jigak (C. aurantium) by 201.23 mg/100 mL in the late August, respectively. The highest contents of nob-iletin, sinensetin and tangeretin among polymethoxyflavones were found in the juice of Hongkyool (C. tachibana) by 7.39 mg/100 mL, 2.24 mg/100 mL, 0.63 mg/100 mL in the late August, respectively. 3,5,6,7,8,3',4'- Heptamet- hoxyflavone recorded the highest amount in Punkyool (C. tangerina) by 0.27 mg/100 mL in the late August, but the other polymethoxyflavones including 3',4',7,8-tetramethoxyflavone, 3',4'-dimethoxyflavone, 4'-methoxyflavone, 5,6,7,3',4',5'-hexamethoxyflavone, scutellarein tetramethylether were observed only trace amount in all the citrus fruits. Flavonoid contents in the citrus fruit juices were the highest during early maturation and decreased rapidly while ripening. Total polyphenol contents were the highest in the late August and decreased with ripening. However from the late December, the contents were increased again. Antioxidant activities of the fruits were evaluated as electron donating ability and were the lowest in the late September and increased with the fruit ripening. These results suggest that quercetagetin among all the flavonoids was most plentiful in Jigak and Dangyooja (C. grandis), so that the fruits could be used for industrial material of flavonoids and antioxidant agents.

• Food Science and Preservation
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• v.18 no.2
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• pp.208-211
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• 2011

Limonoids are abundant as bitter taste in citrus fruit and other plants. Interestingly. limonoid UDP-glucosyltransferase (LUGT) effectively ameliorates the bitterness from limonoid. The high level of LUGT expression in Escherichia coli can result in the formation of insoluble aggregates known as inclusion bodies. We isolated the soluble LUGT protein when this inclusion body was renaturated with ${\beta}$-cyclidextrin treatment after protein denaturation by urea. Our present results suggest that the isolation of LUGT from inclusion body in cells leads to shed light to characterize the enzyme for food industry purposes.

• Food Science and Preservation
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• v.14 no.2
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• pp.160-164
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• 2007

This study was performed to investigate the effects of mixing methods, storage period, and dilution ratio of Dangyuja-sugar mixture on the customer preferences for Dangyuja-tea. Most sensory characteristics such as bitterness, flavor, and taste are influenced more by mixing methods of Dangyuja-sugar mixtiue than by storage period. The Dangyuja-sugar mixture prepared by slice cutting is preferred to those prepared by operating electric mixer, The preference test showed that the appearance is not influenced by storage period but by mixing methods, whereas the tne and texture is more affected by storage period in which the 24 month storage is preferred to 12 month storage. therefore, the overall preference fer Dangyuja-tea is the on that prepared with 20% contents of Dangyuja-sugar mixture which is slice-cut and 24 month stored.