• Korean Journal of Food Science and Technology
• /
• v.45 no.3
• /
• pp.299-304
• /
• 2013

The major hydrophilic bioactive compounds (chlorogenic acid, caffeine, total phenolics, and flavonoids) and the antioxidant capacity in a single size were evaluated for regular coffee varieties commercially available in Korea. The content of total phenols (63.83-110.12 mg gallic acid equivalents) and flavonoids (35.27-69.27 mg catechin equivalents) were spectrophotometrically determined, and the content of chlorogenic acid (5.17-69.78 mg) and caffeine (74.38-146.32 mg) were determined using HPLC-UV. All varieties of regular coffee studied showed antioxidant potential (88.78-487.52 mg trolox equivalents/serving size), which was conferred by their concentrations of phenolic compounds, caffeine and chlorogenic acid. There were significant (p<0.01) correlations between the total phenolics ($r^2$=0.732) and flavonoids ($r^2$=0.8705) and the antioxidant capacity, suggesting that these components were likely a significant contributor to the antioxidant capacity of commercial regular coffee brews.

• Food Science and Preservation
• /
• v.13 no.5
• /
• pp.596-602
• /
• 2006

This study was conducted to investigate the changes of major components and bioactivities of tea produce. The tea produce were made by various methods, with different degree of fermentation during manufacturing process. Except green tea, degrees of fermentation in Wizo Tea, Ilsoae Tea, and Hwang Tea were $5{\sim}10%,\;50{\sim}60%$ and $70{\sim}80%$ respectively. The result are as follows : The general component(moisture, crude ash, crude lipid, and crude protein) and the content of total polyphenol in tea products were not shown significant difference during the fermentation process. The content of caffeine in tea extracts decreased sharply as degree of fermentation of tea. In comparison of hunter values in tea extract, lightness was decreased as fermentation redness (a) was all (-), and yellowness(b) was increased sharpy with degree of fermentation. Radical scavenging activity using DPPH of tow kinds of tea was potent and decreased generally with degree of feimentation. Inhibitory effects of tea extracts against angiotensin I converting enzyme were also potent.

• Korean journal of food and cookery science
• /
• v.11 no.4
• /
• pp.356-361
• /
• 1995

This study was conducted to know the quality of marketed green teas which were devided into high, middle and low grade according to the price. we examined the content of water, ash, total nitrogen, tannin, caffeine, chlorophyll and color value and did sensory evaluation. The results were as follows: 1) The content of water was 2.17-3.67％ and content of ash was 4.50-5.17％, there were no significant difference in each grade. 2) The content of total nitrogen was 4.38％ in high grade, 4.60％ in middle grade and 4.68％ in low grade. 3) The content of tannin was 11.09％ in high grade, 14.22％ in middle grade and 14.44％ in low grade, middle and low grade were significantly higher than high grade. 4) The nitrogen rate to tannin (N/T) was 39.5％ in high grade, 32.6％ in middle grade and 32.70％ in low grade, N/T rate of high grade was significantly highest than others. 5) The content of caffeine is 1.78％ in high grade, 1.32％ in middle grade and 0.92％ in low grade, high and middle grade were significantly higher than low grade. 6) The content of total chlorophyll is 297.37 mg％ in high grade, 192.89 mg％ in middle grade and 204.79 mg％ in low grade, chlorophyll a was 69.23 mg％ in high grade, 51.99 mg％ in middle grade and 63.42 mg％ in low grade, and chlorophyll b was 228.47 mg％ in high grade, 131.21 mg％ in middle grade and 141.63 mg％ in low grade. 7) Yellow value of high and middle grade were significantly higher than low grade, but blue and red value were no significant diffrence in groups. 8) In sensory evaluation, appearance, taste, odor of high grade were better than others and total score was 15.25 in high grade, 12.97 in middle grade and 9.80 in low grade. 9) Price had a positive correlation with caffeine, appearance and taste, but a negative correlation with tannine. NT rate had a negative correlation with tannine, but a positive correlation with caffeine.

• Korean Journal of Plant Resources
• /
• v.20 no.1
• /
• pp.38-42
• /
• 2007

The present study was conducted to investigate the translocation of polyphenols, especially catechin derivatives, from mushroom medium mixed with green tea residues into fruiting body of Pleurotus eryngii. Pleurotus eryngii was grown on the media incorporated by mixing or surface-treated with dry materials including leaf petioles and young stems or leaves of green tea. The dry materials treated in medium did not affect plant height and fresh weight of Pleurotus eryngii body. From the samples of Pleurotus eryngii, the eight main catechin derivatives (-)-gallocatechin(GC), (+)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), (-)-gallocatechin gallate (GCG), (-)-epicatechin gallate (ECG), and (-)-catechin gallate (EGCG), and caffeine were analyzed quantitatively by HPLC. The results showed that EGC in Pleurotus eryngii was 45% more detected, when incorporated with the dry materials, than untreated control. Especially, content of EGCG was increased in surface-treated Pleurotus eryngii up to 3.2 ppm, while it was not detected or reduced in control and other treatments. Caffeine content was greatly increased regardless of treatment method, compared with control (0.1ppm), showing 44 fold-amount in Pleurotus eryngii at early growth stage when incorporated with the dry materials into medium. The results indicates that functional catechin derivatives of green tea would be partly translocated into Pleurotus eryngii throught incorporation and surface treatment with residues of green tea plants.

• The Korean Journal of Community Living Science
• /
• v.19 no.1
• /
• pp.55-61
• /
• 2008

This study was conducted to compare the nutrient and chemical contents of traditional Chungtaejeon tea with that of green tea which was harvested in Jangheung, Jeonnam district. Vitamin C, amino acids and total nitrogen contents of Chungtaejeon tea were lower than that of green tea by 0.30, 2.30 and 4.20g/100g, respectively. The tannin, caffeine, reducing sugar and chlorophyll contents in Chungtaejeon tea were the same as those in green tea. Comparing catechin contents, catechin (C), epicatechin (EC), and epigallocatechin (EGC) in Chungtaejeon tea were lower than those of green tea. However, gallocatechin (GC), epicatechin gallate (ECG), epigallocatechin gallate (EGCG) and catechin gallate (CG) showed no significant difference between Chungtaejeon tea and green tea. The flavonoid contents of Chungtaejeon tea and green tea showed higher quercetin and kaempferol contents in green tea, and higher myricetin content in Chungtaejeon tea. The measured amino acid contents for threonine and aspartic acid were lower, and for glutamic acid were higher in Chungtaejeon tea compared with those in green tea. However, free amino acid content in Chungtaejeon tea and green tea showed no significant difference. Potassium and magnesium contents in Chungtaejeon tea were lower compared to green tea but no significant difference was found for iron, manganese or calcium contents when comparing the two teas.

• Korean Journal of Plant Resources
• /
• v.18 no.2
• /
• pp.351-358
• /
• 2005

The effects of thiamine-HCl or polyvinylpyrrolidone (PVP) on growth and catechin contents of calli from Camellia sinensis leaves were investigated to improve catechin productivity in callus cultures on the selective medium. The growth of calli was great on the proliferation medium (the MS medium with 0.2 mg/L 2,4-D and 1.0 mg/L TDZ) supplemented with $20{\sim}30\;mg/L$ thiamine-HCl. Although the caffeine content was low in calli compared to young leaves, the total content of catechins was high in calli. Particularly,(-)-epicatechin (EC) which not detected in young loaves was also detected in calli on the propagation medium containing thiamine-HCl or PVP. In addition, the (-)-epicatechingallate (ECG) content was significantly higher in calli than in young leaves. In conclusion, the proliferation medium supplemented with 30 mg/L thiamine-HCl as a vitamin source seemed to be optimal condition for the growth and catechin production in callus culture.

• Toxicological Research
• /
• v.13 no.1_2
• /
• pp.117-125
• /
• 1997

In order to assess the possibility whether CYP2D is involved in caffeine metabolism, we have purified and characterized the rat liver microsomal cytochrome P4502D1 (CYP2D1), equivalent to CYP2D6 in human liver, and have utilized the reconstituted CYP2D1 in the metabolism of 4 primary caffeine (1, 3, 7-trimethylxanthine) metabolites such as paraxanthine (1, 7-dimethylxanthine), 1, 3, 7-trimethylurate, theophylline (1, 3-dimethylxanthine) and theobromine (3, 7-dimethylxanthine). Rat liver CYP 2D1 has been purified to a specific content of 8.98 nmole/mg protein (13.4fold purification, 1.5% yield) using $\omega$-aminooctylagarose, hydroxlapatite, and DE52 columns in a sequential manner. As judged from sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), the purified CYP2D1 was apparently homogeneous. Molecular weight of the purified CYP2D1 was found to be 51, 000 Da. Catalytic activity of the purified and then reconstituted CYP2D1 was confirmed by using bufuralol, a known subsFate of CYP2D1. The reconstituted CYP2D1 was found to produce to 1-hydroxylbufuralol at a rate of 1.43$\pm$0.13 nmol/min/nmol P450. The kinetic analysis of bufuralol hydroxylation indicated that Km and Vmax values were 7.32$\mu M$ and 1.64 nmol/min/nmol P450, respectively. The reconstituted CYP2D1 could catalyze the 7-demethylation of PX to 1-methylxanthine at a rate of 12.5 pmol/min/pmol, and also the 7- and 3- demethylations of 1, 3, 7-trimethylurate to 1, 3-dimethylurate and 1, 7-dimethylurate at 6.5 and 12.8 pmol/min/pmol CYP2D1, respectively. The reconstituted CYP2D1 could also 3-demethylate theophylline to 1-methylxanthine at 5 pmol/min/pmol and hydroxylate the theophylline to 1, 3-dimethylurate at 21.8 pmol/min/pmol CYP2D1. The reconstituted CYP2D1, however, did not metabolize TB at all (detection limits were 0.03 pmol/min/pmol). This study indicated that CYP2D1 is involved in 3-and 7-demethylations of paraxanthine and theophylline and suggested that CYP2D6 (equivalent to CYP2D1 in rat liver) present in human liver may be involved in the secondary metabolism of the primary metabolites of caffeine.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.5
• /
• pp.639-645
• /
• 2017

Differences in bioactive compounds and antioxidant activities of aronia leaf (AL) extracts according to manufacturing conditions such as different number of pan-roasting and different temperatures were investigated. Both total polyphenolic compounds and total flavonoids contents were the highest in six time-pan-roasted AL tea extract ($37.96{\pm}0.48mg$ catechin equivalent/g and $19.96{\pm}0.44mg$ quercetin equivalent/g, respectively) among four tea samples. Antioxidative activities were also the highest in six time-pan-roasted AL tea extract with $IC_{50}$ 0.43 mg/mL and $IC_{50}$ 0.27 mg/mL based on DPPH and ABTS radical scavenging activities, respectively. HPLC analysis revealed that AL tea infusion did not have caffeine regardless of manufacturing conditions, whereas green tea infusion had 3.8 mg/g caffeine. Results demonstrated that AL tea can be expected as caffeine free leaf tea containing antioxidant benefits. Moreover, specific pan-roasting conditions of AL tea would be very important for its functional and sensory attributes.

• Food Science of Animal Resources
• /
• v.37 no.2
• /
• pp.305-312
• /
• 2017

This study was conducted to establish the shelf-life of a milk beverage product supplemented with coffee extracts. Qualitative changes including peroxide value (PV), microorganism content, caffeine content, and sensory evaluation were measured periodically in beverages kept at 10, 20, and $30^{\circ}C$ for 8 wk. Lipid oxidation of the product was measured by peroxide value analysis, and apparent changes were observed during a 4 wk storage period. Caffeine analysis revealed that the changes in caffeine content were negligible during the storage period. Total aerobic bacteria, Escherichia coli, yeast, and mold were not detected in the products during an 8 wk storage period. Sensory evaluation revealed that after 4 wk of storage overall acceptance was less than 3 points on a 5-point scale. In this study, PV was used as an indicator of the shelf-life of the milk beverage product. PV analysis revealed that a value of 20 meq/kg was the end of the shelf-life using the Arrhenius equation and the accelerated shelf-life test (ASLT). Assuming that the beverages are kept at $4^{\circ}C$ during distribution, calculation of when the PV reached the quality limit point (20 meq/kg) was done with the equation ln(PV) = 0.3644X - 2.21834 and, using that equation, $PV=e^{0.3644X-2.21834}$ was calculated. Therefore, 14.3086 wk was determined to be the shelf-life of the milk beverage supplemented with coffee when stored at $4^{\circ}C$.

• Journal of Food Hygiene and Safety
• /
• v.13 no.4
• /
• pp.377-382
• /
• 1998

This study was carried out to measure the contents of moisture, crude ash, crude fat, total amino acid, with amino acid composition, vitamin C, ${\beta}-carotene$, vitamin E, total catechins, EGCG, EGC, ECG, EC, GA, caffeine, theobromine and theophylline of the green tea I, II, III, oolong, and black tea. The content of crude fat of green tea I, II, III, oolong, and black teas was 1.1, 2.5, 4.9, 0.8 and 1.2% respectively, total amino acid content was 0.87, 0.78, 0.60, 0.63 and 1.05% respectively, and theanine content was 0.52, 0.48, 0.31, 0.41 and 0.61%, respectively. Total amino acid content of green tea increased in the order of green tea I> green tea II> green tea III, and among the teas, the content of theanine was the highest in the amino acids present. The content of vitamin C of green teal, II, III, oolong, and black tea was 101.6, 87.5, 95.9, 99.1 and 108.0 mg%, respectively, ${\beta}-carotene$ content was 270, 268, 481, 80 and 181 ppm, respectively. Among the ${\alpha}-,\;{\beta}-,\;{\gamma}-\;and\;{\delta}-tocopherol$, the content of ${\alpha}-tocopherol$ was the highest in vitamin E present, and ${\beta}-\;and\;{\delta}-tocopherol$ were not detected in the samples of green teal, II, III, oolong, and black teas. The total catechins of green teal, II, III, oolong, and black teas was 10.5, 10.4, 7.2, 8.4 and 1.8% respectively, and among them, EGCG content was the highest. The content of EGC increased in the order of green tea I > green tea III > green tea II > oolong tea> black tea. The contents EGCG and ECG increased in the order of oolong tea> green tea I > green tea II> green tea III> black tea, and the highest contents of EGCG and ECG were observed in the samples of oolong tea. The content of GA was 0.01, 0.02, 0.05, 0.13 and 0.31%, respectively, and the highest contents of GA, caffeine and theobromine were observed in the sample of black tea. The highest content of theophylline, however, was observed in the sample of green tea I.