• Korean journal of food and cookery science
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• v.24 no.4
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• pp.460-465
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• 2008

The objective of this study was to evaluate the antioxidant properties and sensory qualities of citron peel tea, and to determine the optimum ratio of citron peel powder for its preparation. Yuza peel powders were prepared with citron peel tea at weight 2 and 3 g, respectively. Then, color values(L-value, redness, and yellowness), total phenol content, total antioxidant activity, DPPH radical scavenging activity, and sensory characteristics were measured in the tea samples. The pH of the citron peel tea decreased with increasing preparation temperature. And as the amount of citron peel powder increased, total phenol content, antioxidant capacity, and radical scavenging activity increased. The level of total phenolics in the tea had a higher correlation with total antioxidant capacity($r^2$ = 0.731). Depending on the level of added yuza powder, significant differences(p < 0.05) were shown for aroma, color, and overall acceptability however, there were no significant differences in sourness and bitterness.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.851-858
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• 2005

This study investigated the most desirable mixture ratio of citron preserved in sugar to rice flour for Yuza Sulgidduk(Sulgidduk added with Citron). The moisture contents were $39\~40\%$ The L-value was decreased with increasing addition of Citron, while a- and b-values were increased. The pH was increased with addition of citron. In the mechanical evaluation, hardness was the highest at $\0%$ and the lowest at $26\%$ citron content during the storage period. Cohesiveness was decreased and adhesiveness was increased during the storage period. Springiness showed little difference among the different levels of citron addition. Gumminess decreased with increasing citron content. Brittleness was the highest at $0\%$ level and the lowest at $26\%$ level. In the sensory test characteristics, the color, flavor, sweetness, sourness, astringency were increased with addition of citron. The softness, moistness, chewiness and the overall-acceptability were the highest at $20\%$ level. Consequently, Yuza Sulgidduk with the addtion of $20\%$ citron to rice flour was determined to be the best recipe in terms of the sensory test results.

• 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 fish pathology
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• v.23 no.3
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• pp.389-398
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• 2010

Effects of various concentration of yuzu Citrus junos Siebold ex Tanaka in the diets on growth, blood chemistry and disease resistance of olive flounder were determined. Fifteen hundred fish averaging 200~270g were fed on moist pellet containing yuzu at the concentrations of 0%(control), 2.5%, 5% and 7.5% for 3 months. After feeding trial, weight gain of fish fed 2.5% and 5.0% yuza diet was higher than those of fish fed 0% and 7.5% yuza diet but not significant(P>0.05). No differences in hematological and physiological indices of olive flounder were found among the experimental diets except for total cholesterol. Serum lysozyme activity was not significantly different among fish fed experimental diets but bactericidal activity of fish fed 7.5% yuza diet was significantly different from those of fish fed 0, 2.5 and 5% Yuza diets. Survival rates of fish fed 2.5% yuza diet at experimental infection with Edwardsiella tarda and Streptococcus sp. were higher than those of the other experimental groups but not significant. In conclusion, Dietary inclusion of 2.5~5% yuzu seems to have positive effects for fish health condition and disease resistance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1485-1491
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• 2009

The biological compounds such as vitamin C, carotenoids, hesperidin and naringin were determined in Yuza grown in Geoje, Goseong, Gohung and Namhae. Also, activities of electron donating, nitrite scavenging and tyrosinase were detected by concentration of water extracts made from Yuza peel. Vitamin C contents of flesh sample were 6.34${\Pm}$0.12-10.74${\Pm}$1.25 mg/100 g and its contents of peel were 2.17-3.57 times higher than flesh. The carotenoid contents of peel were higher than flesh, and its contents were abundant (over 6.0 mg/100 g) in peel of Yuza grown in Goseong and Namhae-native, while Goheung-native and improved samples were detected below 3.6 mg/100 g. The contents of total phenols were the highest in flesh (11.11${\Pm}$0.10 mg/100 g) and peel (31.76 mg/100 g) of Namhae-improve Yuza. The contents of hesperidin and naringin were about 4.81-7.80, 3.07-4.62 times higher in peel than flesh. Electron donating ability of water extracts made from Yuza peel was 52.78${\Pm}$1.13-66.88${\Pm}$0.53%, in over 5 mg/mL; especially, its ability in Namhae sample was significantly high in reaction system added over 5 mg/mL of water extracts. Nitrite scavenging ability in all samples was below 30% in reaction system added 1 mg/mL of water extracts. Inhibition activity of tyrosinase in reaction system added 2.5 mg/mL of water extracts was only observed in Namhae samples, but the other samples were increased in reaction system added over 5 mg/mL of water extracts.

• Korean journal of food and cookery science
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• v.26 no.1
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• pp.79-87
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• 2010

The antioxidant activity of hot water extracts made from Yuza (Citrus junos SIEB ex TANAKA) cultivated in Namhae Changseon, Seolcheon and Idong-myeon was analyzed. The total phenolic compound content was significantly higher in the Seolcheon sample (116.06 mg/100 g) than in Idong or Changseon. Flavonoids and hesperidin contents were not significantly different among samples. The electron-donating ability of the Yuza peel hot water extracts was activated to over 55% in all samples with $5,000\;{\mu}g/mL$ added to the reaction system, with especially high in the Seolcheon sample (85.70%). Also, the reducing powder in $10,000\;{\mu}g/mL$ added to the reaction system was showed significantly higher in the Seolcheon (0.82) than in the other samples. The ABT cation decolorization capacity of Yuza peel extracts was activated to over 50% in all samples when $5,000\;{\mu}g/mL$ of water extracts were added to the reaction mixture, and the activity was the highest (67.59%) in the Idong samples. The nitric oxide scavenging activity was lower than 45% in all samples, with the activity of Changseon significantely lower than the other samples. The antioxidant activity of the $\beta$-carotene linoleic acid system was 33.30~42.22% when $1,000\;{\mu}g/mL$ water extracts was added to the reaction mixtures, of which the activity in the Yuza cultivated in Seolcheon showed the highest.

• Journal of Life Science
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• v.26 no.5
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• pp.563-570
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• 2016

Onion vinegar has an undesirable flavor and taste that results from alcohol and acetic acid production from fermentation. In this study, we have used onion vinegar to develop an onion vinegar beverage with better sensory quality. The objective of this study was to determine the optimum blending ratio by using response surface methods to produce an onion vinegar beverage containing Yuza (Citrus junos Sieb ex Tanaka). The optimal formula for a fermented onion beverage was determined using a central composite design by the response surface methodology. The independent variables were obtained by regression analysis of the reaction surface of brown sugar, apple extracts and Yuza extracts. The optimum mixing ratio for onion vinegar:water:brown sugar:apple extracts:Yuza extracts was 6.0:77.6:4.9:9.2:2.3 (w/w). The actual overall acceptance was 7.08 under optimum conditions, which was close to the maximum predicted value of 6.96. The concentration of phenolic compounds, total flavonoids, and quercetin present in the onion vinegar beverage was 14.8 mg/100 g, 2.6 mg/100 g and 1.4 mg/100 g, respectively. The onion vinegar beverage showed antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Enterobacter aerogenes. It also showed antioxidant effects, with a DPPH radical inhibition rate of 18.2% and superoxide dismutase (SOD)-like activity of 11.5%. In conclusion, the onion vinegar beverage described here seems to have nutritional value and potential biological activity.

• Journal of Life Science
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• v.18 no.12
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• pp.1745-1751
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• 2008

This study was to investigate of characteristics and antioxidant function of yuza from 4 different area. The hot-water extracts of yuza peel extracts from Geoje, Goseong, Goheung and Namhae(Changseon, Seolcheon) were tested for antioxidant activity in different reaction systems. Contents of total phenolic compounds and flavonoids were $122.18{\pm}1.44$ mg/100 g and $114.39{\pm}0.94$ mg/100 g in hot water extracts from Namhae-Seolcheon, respectively. The highest contents of hesperidin and naringin were $55.45{\pm}1.36$ mg/100 g and $28.41{\pm}0.64$ mg/100 g in hot water extracts from Geoje, respectively. Antioxidant activity of yuza peel hot-water extracts were significantely increased as the increament of sample adding concentration ($500{\sim}10,000{\mu}g$/ml). Reducing power was $6{\sim}9$ folds higher in 10,000 ${\mu}g$/ml concentration than 500 ${\mu}g$/ml and it's O.D. value showed $0.68{\pm}0.012{\sim}0.97{\pm}0.021$. ABTs scavenging activity was more than 80% in 10,000 ${\mu}g$/ml concentration samples, except from Goseong ($78.13{\pm}1.30%$). Hydroxyl radical scavenging activity was higher in Namhae-Seolcheon ($31.36{\pm}1.36%$) and Namhae-Changseon ($30.28{\pm}1.60%$) at 10,000 ${\mu}g$/ ml concentration, others activity were below 30%. At 10,000 ${\mu}g$/ml concentration, NO radical scavenging activity and antioxidant activity in ${\beta}$-carotene linoleic acid system were $26.49{\pm}1.77{\sim}40.85{\pm}0.95%$ and $24.40{\pm}1.91{\sim}38.17{\pm}0.56%$, respectively.

• Food Science and Preservation
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• v.24 no.6
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• pp.802-812
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• 2017

This study was conducted to investigate the quality properties depending on the cultivation methods (general, organic, pesticide-free) of yuza and its various parts (peel, pulp, seed). The contents of hesperidin were the highest in yuza feel grown by pesticide-free method (13.23 mg/g). The contents of naringin presented a higher content in the peel, especially which of the general (4.62 mg/g) showed the highest value. Vitamin C analysis showed the highest content in the peel, significantly varied according to the cultivation method and various parts (p<0.05). Vitamin C value was significantly highest in organic peel, which was 770.02 mg/100 g, whereas among the peel, the pulp and the seed were it the lowest in the seed. The content of total polyphenols were the highest in general peel (0.85 mg/g). Flavonoid content of pesticide-free seed was significantly higher than those of the other yuja samples which was 0.89 mg/g (p<0.05). The DPPH radical scavenging activity was relatively more active in the peel among the above-mentioned three parts, especially the pesticide-free peel was most active, which was 73.94%. The ABTS radical scavenging activity of organic peel was significantly active among the samples, which was 84.47% (p<0.05). Based on these results, it can be said that yuja has variety of useful components in the pulp and the seed as well as the peel: and thus it's hight recommended to develop more varied yuja products.

• Journal of the Korean Society of Food Culture
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• v.37 no.2
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• pp.133-142
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• 2022

The purpose of this research was to examine the preferences of five traditional Korean drinks and analyze the factors affecting the preferences of children aged 7-12 in Korea, Vietnam, and China. The samples used in a sensory test were omija-cha, yuza-cha, sujeonggwa, sikhye and misutgaru. The test was performed to examine the overall, appearance (color), odor, taste and mouth-feeling and a sweetness intensity using 5 point hedonic scale (1=dislike extremely, 5=like extremely) and, check-all-that-apply (CATA) method was performed to determine preference and non-preferences factors. The preference of all samples except sujeonggwa showed significant differences in all items of the preferences (p<0.001). Almost items of the preference was rated more than 4 points in Chinese and Korea children. The sweetness intensity showed also significant differences in all items of the preferences except sujeonggwa (p<0.001), and evaluated as not sweet-appropriate with the score between 2 and 3 points. Sweetness, color, mouth-feeling, familiar flavor and healthy feeling was selected for the factors affecting the preferences. In conclusion, the result of this study determine the preferences and the affecting factors for the traditional Korean drinks in children of Korea, Vietnam, and China.