• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.107-113
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• 2006

These studies were carried out to investigate the quality of green tea processed by different pan-firing hand rolling and to select the best conditions during the procedure of green tea processing the results were as follows. At harvestion tea plant leaf, tea plants had 4 leaves. each leaf size was 7.5 cm'$\square$2.6 cm, and weight of 100 buds 46.6 g. The increase of pan-fired time decreased in the moisture content and yield of green tea. After processing green tea, 5 times pan-fired one had much more contents of total nitrogen (T-N:5.31%), caffeine (2.00%) and total amino acid (T.A.A. : 3,046 mg%) and less content of tannin (13.41%) than the other treatments. but 3 times pan-fired one had the highest contents of vitamin C (204.3 mg%) and chlorophyll (365.0 mg%) among three kinds pan-firing method. Sixteen kinds of free amino acid including theanine as a good taste component of pan-fired green tea were isolated and measured by HPLC. Free amino acid (FAA) contents were in the range of $2,683{\sim}2,925$ mg% and among various pan-firing methods, 5 tims pan-fired one had the highest content of F.A.A. Among these free amino acids, theanine occupied as much as $56.4{\sim}61.3%$ of F.A.A. Lightness, yellowness and redness of 5 times pan-fired green tea were middle value among three different treatments. Besides, it gained the highest score of sensory evaluation among them. These above results suggested that 5 times pan-fired green tea was considered to be the best level as pan-firing times of green tea processing.

• Korean Journal of Medicinal Crop Science
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• v.7 no.2
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• pp.101-106
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• 1999

These studies were carried out to investigate the quality of green tea processed by different 1st-pan-firing time and to select the best conditions of green tea processing. The results were as follows. At harvesting tea plant leaf, tea plants had 4 leaves, each leaf size was $6.4cm\;{\times}\;2.4cm$, and weight of 100 buds was 40.2g. The content of moisture of green tea was decreased with the prolongation of 1st-pan-firing time, and the yield of green tea at 10 min. pan-firing time was the highest value of 20.12%. After processing green tea, 1st 10 min. pan-fired one had much more contents of total nitrogen(TN 5.41%) and total amino acid(T.A.A; 3,282mg/100g) and less content of tannin(13.22%) and caffeine(1.64%) than the other treatments. The content of chlorophyll and vitamin C went down with the extension of 1st pan-firing period. Sixteen kinds of free amino acid including theanine as a good taste component of green tea were isolated and measured by HPLC. T.A.A contents were in the range of $2,447{\sim}3,192mg/100g$ and among various pan-firing methods, 10 min. 1st pan-fired one had the highest content of T.A.A. The taste-determinants such as theanine, aspartic acid, serine, glutamic acid and arginine in green tea liquor, occupied as much as $89.4{\sim}90.0%$ of T.A.A.s. Among these, theanine was more than 50%, Lightness and yellowness of green tea were increased with delay of pan-firing time, while green color appeared to be more distinct at 10 min. 1st pan -firing time than other treatments. Besides, it gained the highest score of sensory evaluation among them. These above results suggested that 10 min. pan-fired green tea was considered to be the best level as pan-firing time of green tea processing.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.05a
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• pp.192-195
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• 2005

• Korean Journal of Food Science and Technology
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• v.40 no.3
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• pp.297-302
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• 2008

In this study, Chrysanthemum indicum L. flower tea was prepared according to different pan-firing times (5, 7.5, 10, 12.5, and 15 min) and its quality characteristics were investigated. Total nitrogen and tannin contents increased with increasing pan-firing time, whereas chlorophyll and total amino acid (AA) contents decreased. The total AA contents of the samples ranged from 6,399 to 7,068 mg%, and the highest content (7,068 mg%) was found with the 10 min panfiring treatment. The AAs occurring in the C. indicum L. flower tea included glutamic acid and aspartic acid, which are desirable flavor components. As the pan-firing time increased, antioxidant activity as well as total polyphenol and flavonoid contents increased. The highest total polyphenol and flavonoid contents were found in the 15 min treatment at levels of 13.85 mg tannic acid equiv./g and 9.77 mg catechin equiv./g, respectively. The 15 min pan-firing treatment also had the highest total antioxidant activity at 19.33 mg ascorbic acid equiv. eg/100 g. Finally, based on sensory evaluations, the 10 min pan-fired C. indicum L. flower tea had the best overall quality.

• Food Science and Preservation
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• v.15 no.3
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• pp.461-468
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• 2008

To obtain basic da1a on the preparation of Cudrania tricuspidata leaves tea, the quality and anti-oxidative characteristics of dried raw leaves (RT), pan-fired leaves tea (PT) and fermented leaves tea (FT) were investigated. General characteristics of RT, PT and FT, respectively, were: moisture content 18.47, 6.23 and 8.50%; crude protein content 17.77, 20.46 and 19.13%; and carbohydrate content 54.42, 62.52 and 61.96%. The crude lipid and ash contents were in the range 0.05 - 0.07% and 9.27 -10.74% respectively; the water soluble solid content was in the order FT > PT > RT and ranged from 23.10 - 37.38%; there were no significant differences in the total polyphenol content (815.24 - 835.16 mg%). Although $L^*$ values of PT (20.94) and FT (20.85) were lower than those of RT (34.71), the $a^*$ value in PT and the $b^*$ value in FT were highest. In all ethanol extracts the reducing power, electron-donating ability and superoxide dismutase (SOD)-like activity increased in a concentration-dependent manner. Furthermore, the activity in FT was higher than in PT or RT. The total free amino-acid content was higher in FT (1429.93 mg%) than RT (1108.94 mg%) or PT (833.13 mg%). The major amino acids were L-asparagine and L-valine in RT, L-cysteine and L-glutamic acid in PT and L-proline in FT. In a sensory evaluation of PT and FT, bitter and astringent tastes were decreased relative to RT, while sweet and savory tastes, flavor, color and overall acceptability were increased. These results indicate that FT bas a higher antioxidant effect and free-amino-acid content than PT, while the sensory quality of FT is similar to that of PT.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.4
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• pp.516-523
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• 2008

The effects of pan-fired (PM) and fermented (FM) Cudrania tricupidata tea leaves on $\alpha$-glucosidase inhibitory activity, oral glucose tolerance, blood glucose levels and serum lipids profiles in streptozotocin (STZ)-induced hyperglycemic rats were investigated. The $\alpha$-glucosidase inhibitory activity of FM ethanol extracts (20 mg/mL) was higher (92.5%) than that of raw dried leaves (RM) (69.1%) and PM (54.6%). In addition, the results of a glucose tolerance test revealed that the glucose levels of hyperglycemic rats that were fed PM and FM ethanol extracts and then orally administered glucose began to decrease after 60 minutes, but recovered after 120 minutes. However, the blood glucose levels in the hyperglycemic control group did not begin to decrease for 360 minutes. Additionally, the results of animal experiments that were conducted over five weeks to compare the dietary effects of PM and FM following hyperglycemic induction to the effects on the hyperglycemic control group (DM) were as follows: The body weight gain and FER of the treated rats were $12.9{\sim}16.9%$ higher than those of the DM group, whereas the amounts of feed and water intake by the treated rats were $6.8{\sim}10.1%$ lower. Additionally, the levels of blood glucose and serum fructosamine decreased by $27.3{\sim}39.8%$ and $6.7{\sim}20.0%$, respectively, in the treated rats. Moreover, the serum triglyceride, total cholesterol and LDL-cholesterol concentrations in the treated rats were $24.9{\sim}27.1%$, $15.9{\sim}17.4%$ and $33.8{\sim}38.4%$ lower, respectively. Finally, the HDL-cholesterol contents were $20.5{\sim}24.8%$ higher in the treated rats than in the control group. The above results suggest that PM and FM exerts an anti-hyperglycemic effect that occurs due to the inhibition of $\alpha$-glucosidase activity as well as via prevention and/or inhibition of changes in the serum lipid profile. In addition, the results of this study revealed that the synthetic anti-hyperglycemic effect of FM was greater than that of PM. However, further detailed studies are needed to confirm these results.