• 한국식물병리학회지
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• 제11권4호
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• pp.383-385
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• 1995

Occurrence of white scab of tea (CAmellia sinensis) showing numerous, small, circular, reddish or yellowish brown spots on young tea leaves was observed at a tea plantation of Boseung, Chonnam, from May to June in 1992-1994. At the late growth stages, the center of the spot became light gray. The causal fungus of the white scab was identified as Sphaceloma theae Kurosawa. Symptoms were produced 5∼6 days after inoculation by the artificial inoculation of s. theae conidia, which was similar to those on naturally infected leaves.

• 한국식품영양학회지
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• 제28권5호
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• pp.766-773
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• 2015

This study analyzes the chemical composition of green tea, white tea, yellow tea, oolong tea and black tea with respect to extraction temperature and time. The optimum extraction conditions for these teas were determined by assessing the chemical composition of tea brewed at different temperature (50, 60, 70, $80^{\circ}C$) and extraction times (1, 3, 5, 10 minute). Catechins contents were the largest at 5 minutes and generally declined by 10 minutes. Green tea catechins contents were highest when brewed at $70^{\circ}C$ and besides other teas a change of the trend variation at 70 and $80^{\circ}C$. These temperatures did not extract theaflavins in green tea. Extract temperature and time did not significantly affect theaflavins content of white tea, yellow tea, and oolong tea. Black tea, however, was noticeably dependent on extract conditions, which were most effective at $70^{\circ}C$, brewed for 5 minutes. Caffeine content of green tea, yellow tea, and oolong tea was highest at 5 minutes, but temperature did not appear to affect the content. White tea and black tea caffeine content was highest when brewed at $70^{\circ}C$ for 5 minutes. Theobromine content of green tea, yellow tea, oolong tea, and black tea did not show major differences between the study times or temperature, though the content in white tea increased with higher temperatures when brewed for 5 minutes. The extraction of phenolic compounds increased until 5 minutes, and showed not further increase at 10 minutes. Antioxidant capacity of green tea, white tea, and yellow tea were maximized at $70^{\circ}C$ for 5 minutes or $80^{\circ}C$ for 3 minutes, while oolong and black tea were reached maximum antioxidants at $70^{\circ}C$ for 5 minutes. In general, to optimize the beneficial chemical content of brewed tea, a water temperature of $70^{\circ}C$ for 5 minutes is recommended.

• 한국축산식품학회지
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• 제41권5호
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• pp.840-854
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• 2021

The impact of green tea extract powder and rosemary extract powder, alone or in combination, on the quality characteristics of naturally cured pork sausages produced with white kimchi powder as a nitrate source was evaluated. Ground pork sausages were assigned to one of seven treatments: control (0.01% sodium nitrite and 0.05% sodium ascorbate), treatment 1 (0.3% white kimchi powder and 0.05% green tea extract powder), treatment 2 (0.3% white kimchi powder and 0.1% green tea extract powder), treatment 3 (0.3% white kimchi powder and 0.05% rosemary extract powder), treatment 4 (0.3% white kimchi powder and 0.1% rosemary extract powder), treatment 5 (0.3% white kimchi powder, 0.05% green tea extract powder, and 0.05% rosemary extract powder), and treatment 6 (0.3% celery juice powder, 0.05% green tea extract powder, and 0.05% rosemary extract powder). Naturally cured products had lower (p<0.05) cooking yield and residual nitrite content than control sausages. However, compared to the control, naturally cured products with white kimchi powder (treatments 1 to 5) showed similar the pH, oxidation-reduction potential, CIE L^* values, CIE a^* values, nitrosyl hemochrome content, total pigment content, and curing efficiency to the control. When the amount of green tea extract powder or rosemary extract powder was increased to 0.1% (treatments 2 and 4), lipid oxidation was reduced (p<0.05). These results indicate that green tea extract powder, rosemary extract powder, and white kimchi powder may provide an effective solution to replace synthetic nitrite and ascorbate used in traditionally cured products.

• 한국식품과학회지
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• 제54권2호
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• pp.228-234
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• 2022

Various types of tea have been cultivated to obtain different flavors and enhance their functional properties. The objective of this study was to investigate the physicochemical properties of γ-aminobutyric acid (GABA) teas produced from commercial Korean green, white, and black teas. The concentration of total minerals was reduced in GABA green tea and GABA white tea but was improved in GABA black tea. The essential, non-essential, and total free amino acid contents were remarkably increased in the GABA teas. The amino acid GABA content was increased by 561.00 and 294.20 times in GABA white tea and GABA black tea, respectively. The antioxidant potential was not reduced, although the total polyphenol and total flavonoid contents decreased in GABA green tea and GABA black tea. The results indicated that the overall nutritional value of commercial green, white, and black teas could be improved by processing them into GABA teas.

• 한국축산식품학회지
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• 제34권4호
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• pp.403-407
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• 2014

Changes in Maillard reaction of pidan white were monitored with $A_{294}$, fluorescence intensity, and browning intensity during pickling in the absence and presence of Chinese black tea extract (Camellia sinensis) at levels of 2% and 5% together with 0.2% $ZnCl_2$ or 0.2% $CaCl_2$ up to 3 wk, followed by ageing for another 3 wk. Browning intensity and $A_{294}$ of pidan white increased with increasing pickling/ageing, while fluorescence intensity decreased during ageing (p<0.05), irrespective of treatments. At wk 6, pidan white treated with 0.2% $ZnCl_2$ and 0.2% $CaCl_2$ showed slightly higher browning intensity, fluorescence intensity and $A_{294}$ than those treated with divalents together with Chinese black tea (p<0.05). Free amino group and sugar contents showed continuous decrease during pickling and ageing irrespective of tea and cations used. However, pidan treated without Chinese black tea extract showed significantly lower free amino group and sugar during the ageing of 6 wk (p<0.05). Thus, Chinese black tea extract had an inhibitory effect on the Maillard reaction during ageing of pidan white.

• 한국식품조리과학회지
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• 제15권4호
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• pp.395-400
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• 1999

가루녹차의 식빵 적성을 검토하기 위하여 가루녹차를 0, 2.5, 5.0, 그리고 10%를 첨가한 식빵을 제조하여 품질의 특성을 조사하였다. 아밀로그램의 특성을 보면 가루녹차의 첨가량이 증가할수록 최고점도와 최종점도는 감소하였으나 호화개시온도는 증가하는 경향이었다. 식빵 외부의 L값, a값 및 b값은 가루녹차 함량이 증가할수록 감소하였고, 내부의 색도도 L값과 a값은 가루녹차 첨가량이 많을수록 감소되었고 b값 증가하였다. 식빵의 부피는 가루녹차 5.0%이상 첨가시에 감소하였다. 식빵의 물리적 특성을 보면 견고성 (hardnesss)은 대조군과 2.5% 첨가군에서는 차이가 없었으나 10% 첨가군에서는 유의적으로 높았고, 탄력성(springiness)과 응집성(cohesiveness)은 가루녹차 첨가에 의한 영향이 거의 없었고 전체적으로는 가루녹차 10% 첨가 군에서 높은 값을 나타내었다. 관능검사 결과, 외관, 색, 풍미, 맛, 조직감, 그리고 전반적인 기호도 모두 가루녹차 2.5% 첨가한 식빵이 좋다고 평가되었다. 이상의 결과를 종합해 보면 가루녹차 식빵은 기호도와 전반적인 특성을 볼 때 가루녹차 2.5% 첨가가 가장 우수하였으며 부피 등의 감소에 대하여는 앞으로 더 연구해야 할 과제라고 생각한다.

• Applied Microscopy
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• 제41권3호
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• pp.197-204
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• 2011

백차 열수추출물의 염증 및 피부장벽 손상완화 효과를 알아보기 위해 생후 6~7주령 암컷 SKH-1 hairless 마우스 등 부위에UVB를 12주간 조사하여 피부노화를 유발시킨 후, 실험동물을정상군(N), 대조군(UVB+saline, C), 양성대조군(UVB+0.01%retinoic acid, PC), 실험군1 (UVB+1% white tea water extract, E1), 실험군2 (UVB+2% white tea water extract, E2)로 나누어 1일 2회, 주 5일, 4주 동안 매회 200 ${\mu}L$씩 시료를 도포하여 다음과 같은 결과를 얻었다. (1) 피부 홍반도 측정에서, 실험 4주 후 C군에비해 PC, E1, E2군은 각각 31, 41, 46% 유의하게(p<0.001) 낮았다. (2) 수분함량 측정에서, 실험 4주 후 C군에 비해 PC, E1, E2군은 각각 190, 207, 225% 유의하게(p<0.001) 높았다. 경표피수분 손실량(transepidermal water loss, TEWL) 측정에서, 실험 4주후 C군에 비해 PC, E1, E2군은 각각 61, 79, 85% 유의하게(p<0.001) 낮았다. 조직학적 관찰에서, C군에 비해 E1, E2군은 표피층과 진피층의 비후, 비만세포수와 탈과립 정도가 현저하게 경감되었다. 이상의 연구결과를 종합할 때, hairless 마우스를 이용한in vivo 실험에서 백차 열수추출물 경피 도포는 자외선 조사로 인해 유발된 피부장벽 손상 및 염증 반응에 상당한 개선 효과가 있음을 확인하였다.

• Preventive Nutrition and Food Science
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• 제8권4호
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• pp.377-382
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• 2003

This study investigated the effects of green tea on the muscle antioxidative defense system in the white & red gastrocnemius muscles of rats after aerobic exercise. Male Sprague-Dawley rats weighing 150 10 g were randomly assigned to a control group, non-exercise with green tea group (G group), and exercise training group. The exercise training group was then further classified as the training (T) group and training with green tea (TG) group, the latter of which was supplemented with green tea in the drinking water during the experimental period. The rats in the exercise training groups (T and TG) were subjected to aerobic exercise on a treadmill 30 min/day at a speed of 28 m/min (7% incline) 5 days/week, while the other groups (control and G group) were cage confined for 4 weeks. Thereafter, the rats were sacrificed with an injected overdose of pentobarbital just after running. In the white muscle, the xanthine oxidase (XOD) activities were 71 % higher in the T group compared to control group, whereas the TG group had the same activity as the control group. The XOD activities in the red gastrocnemius muscle exhibited the same tendency as in the white muscle. The superoxide dismutase (SOD) activity in the white muscle was lower in the T group compared with the control group, yet significantly higher in the TG group compared with the T group. The SOD activities in the red gastrocnemius muscle exhibited the same tendency as in the white gastrocnemius muscle. The glutathione peroxidase (GSHpx) activities in the white & red gastrocnemius muscles were 43 % lower in the T group compared with the control group, yet the activities in the TG group remained at control levels. The glutathione S-transferase (GST) activity in the white muscle was not significantly different among any of the three groups, but in the red gastrocnemius muscle, the TG group had the same activity as in the control group. The thiobarbituric acid reactive substance (TBARS) contents in the white & red gastrocnemius muscles were higher in the T group than in the control but the control and TG groups had the same concentrations of TBARS. In conclusion, the supplementation of green tea in rats subjected to aerobic exercise was found to reduce the peroxidation of muscle lipids by enhancing the antioxidative defense mechanism.

• Toxicological Research
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• 제30권4호
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• pp.283-289
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• 2014

Tea flavonoids and polyphenols are well known for their extraordinary antioxidant activity which is considered important for anti-aging processes in animals. This study evaluated the anti-wrinkle effects of three different kinds of tea (Camellia sinensis) water extracts (CSWEs) including green, white, and black teas using a photoaged hairless mouse model. Data showed that the CSWE-treatment greatly improved skin conditions of mice suffering from UVB-induced photoaging, based on the parameters including the skin erythema index, moisture capacity, and transepidermal water loss. In addition, the wrinkle measurement and image analysis of skin replicas indicated that CSWEs remarkably inhibited wrinkle formation. In histological examination, the CSWE-treated mice exhibited diminished epidermal thickness and increased collagen and elastic fiber content, key signatures for skin restoration. Furthermore, the reduced expression of MMP-3, a collagen-degradative enzyme, was observed in the skin of CSWE-treated animals. Interestingly, comparative data between green, white, and black tea indicated that the anti-wrinkle activity of white tea and black tea is equally greater than that of green tea. Taken together, these data clearly demonstrated that CSWEs could be used as an effective anti-wrinkle agent in photoaged animal skin, implying their extended uses in therapeutics.

• 한국식품저장유통학회지
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• 제17권3호
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• pp.328-333
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• 2010

녹차가 계란의 품질 특성에 미치는 영향을 조사하기 위해 녹차 분말을 기존 산란계 사료(대조군)에 4%(A), 8%(B) 첨가하여 10주간 식이하게 한 후 생산된 계란의 이화학적 특성을 분석하여 나타낸 결과는 다음과 같다. Ca, K, P, Fe, Mg 등의 주요 무기질 함량은 계란의 부위(흰자, 노른자)에 관계없이 녹차 함량에 비려하여 증가하는 경향을 보였으나 무기질의 절대 양은 Mg 함량을 제외하면 흰자에서 보다는 노른자에 많았다. 무기질 원소의 증가 비가 가장 큰 원소는 흰자에서는 Ca이온으로 41.0 mg%에서 119.8 mg%로 2.9배 증가하였고, 노른자에서는 Fe이온으로 3.7 mg%에서 12.6 mg%로 3.4배 증가하였다. 계란의 평균 중량은 녹차 식이 양에 비례하여 감소(68.8 g에서 64.4 g)하는 경향이었고, 난황의 총 콜레스테롤 함량은 1899.1 mg%∼2011.3 mg% 으로서 녹차 식이와는 유의 차이가 없었다. 흰자는 녹차 식이와 관계없이 떫은맛을 내고 옅은 회색을 나타내나, 노른자는 녹차 식이를 증가시킴에 따라서 약간 검붉은 색으로, 그리고 비린내가 적은 경향이었다. 계란의 수소이온농도 값은 녹차 식이 양의 증가와 더불어 감소하는 경향이었는데 B 처리군의 흰자, 노른자 및 전체의 값은 각각 8.45, 5.96 및 7.66이었다. 계란 노른자의 주요 지방산은 palmitic acid, stearic acid, oleic acid, linoleic acid 으로서 전체 지방산의 90% 이상을 차지하였고, 녹차 식이 양을 증가시킴에 따라서 포화지방산은 32.0%에서 27.4% 으로 감소하고, 불포화지방산은 68.0%에서 72.6% 으로 증가하는 경향으로 나타났다.