• Food Science and Preservation
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• v.13 no.3
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• pp.389-396
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• 2006

In order to prepare liqueur of citrus fruit, changes of major constituents, flavonoid pH, color changes, and extract, by soaking 3 kg/6 L kumquats for $1{\sim}70$ days and 1 kg/3 L Citrus platymama for $1{\sim}50$ days in $30{\sim}95%$ ethanol solution were investigated 1.5kg of kumquats, and 1kg of citrus platymama were soaked in 3 L of $30{\sim}95%$ ethanol solution for $50{\sim}70$ days. pH and color changed largely by ethanol concentration. Glucose and fructose were more extracted in $60{\sim}95%$ ethanol concentration. Citric acid and malic acid were extracted $10{\sim}15$ times with kumquats than with Citrus platymama in 30% ethanol solution. Ascorbic acid was more extracted in 60% ethanol solution for kumquats, and in 95% ethanol for Citrus platymamma. The content of ascorbic acid was $3.19{\sim}41.91{\mu}g/mL$ in kumquats, and $21.90{\sim}30.12{\mu}g/mL$ in Citrus platymamma. $312.82{\sim}688.12{\mu}g/mL$ of rutin were extracted in 95% ethanol solution, $9.32{\sim}74.49{\mu}g/mL$ of neohesperidin were extracted in 60% ethanol as for kumquats. Rutin and neohesperidin were more extracted in 30% ethanol concentration contrary to hesperidin. Hesperidin was extracted $38.93{\sim}136.86{\mu}g/mL$ in 95% ethanol solution.

• 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.