Jin-Oh Chung

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As tea is traded all over the world, it is necessary for both customs officers and business investigators to develop an easy and reliable method to discriminate teas from each other. A total of 56 kinds of various green, Oolong, and black teas were collected from different countries and markets, and their catechin contents and volatile flavour compounds(More)
The effects of climatic conditions on green tea metabolites in three different growing areas of Jeju Island, South Korea, were investigated through global metabolite profiling by (1)H nuclear magnetic resonance (NMR) spectroscopy. Pattern recognition methods, such as principal component analysis (PCA) and orthogonal projection on latent(More)
BACKGROUND This study was aimed at assessing the therapeutic efficacy of green tea on peripheral skin for cold hypersensitive subjects, who had the feeling of cold hands and feet at cold temperatures, one of the most common complaints in Asian women. METHODS This randomized and placebo-controlled clinical study included 60 female Korean subjects who had(More)
Numerous factors such as geographical origin, cultivar, climate, cultural practices, and manufacturing processes influence the chemical compositions of tea, in the same way as growing conditions and grape variety affect wine quality. However, the relationships between these factors and tea chemical compositions are not well understood. In this study, a new(More)
The effect of green tea formulated with vitamin C and xylitol on intestinal cell transport of gallated and nongallated catechin was studied. The transport of catechins from both apical to basolateral and basolateral to apical directions was measured. The effect of vitamin C (4, 10, 20 ppm), xylitol (11, 27.5, 55 ppm), and combinations of both on the(More)
Quercetin and fisetin, known as catechol-containing flavonoids, could positively affect the absorption of catechins due to their strong affinity for catechol-O-methyl transferase (COMT), which can methylate and cause the excretion of catechins. The current study examined the effect of quercetin and fisetin on the absorption of epi-catechins (ECs) by using a(More)
The impacts of onion peel (OP) and Dendropanax morbifera (DM), as excipient foods rich in flavonols, on the digestive recovery, intestinal absorption, and pharmacokinetics of GT epicatechins were studied via an in vitro digestion model system with Caco-2 cells and an in vivo study. The digestive stability of total epicatechins recovered from GT upon the(More)
BACKGROUND The purpose of this study was to investigate the effect of hydroxypropyl methyl cellulose phthalate (HPMCP) coating on the digestive stability and intestinal transport of green tea catechins (GTCs). METHODS Two types of HPMCP coating were prepared: one type with size smaller than 500 μm (S-HPMCP) and the other with size larger than 500 μm(More)
The dependence of global green tea metabolome on plucking positions was investigated through (1)H nuclear magnetic resonance (NMR) analysis coupled with multivariate statistical data set. Pattern recognition methods, such as principal component analysis (PCA) and orthogonal projection on latent structure-discriminant analysis (OPLS-DA), were employed for a(More)
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