Results 171 to 180 of about 13,311 (204)

Antioxidative Activities of Oolong Tea

Journal of Agricultural and Food Chemistry, 2002
While the antioxidative properties of green and black tea have been extensively studied, less attention has been given to these properties in oolong tea. The reducing powers, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, the amount of total phenolic compounds, the inhibitory effect on FeCl(2)/H(2)O(2) (Fenton reaction system)-induced ...
Qin Yan, Zhu, Robert M, Hackman, Jodi L, Ensunsa, Roberta R, Holt, Carl L, Keen   +4 more
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ELEMENTAL PIXE ANALYSIS OF OOLONG TEA

International Journal of PIXE, 2008
The contamination of heavy metals in food becomes a serious problem. We analyzed oolong tea from different production areas by PIXE using very simple sample preparation and examined trace elements contained in these samples. From the results of this experiment, we could know oolong tea which analyzed in this experiment contains various minerals such ...
M. WATANABE, K. ISHII, S. MATSUYAMA, A. TERAKAWA, Y. KIKUCHI, M. FUJIWARA, Y. KAWAMURA, S. TSUBOI, K. YAMANAKA, S. OKURA, M. FUJIKAWA, H. YAMAZAKI   +11 more
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Comparison of the antioxidant activity of roasted tea with green, oolong, and black teas

International Journal of Food Sciences and Nutrition, 2005
Although the antioxidant properties of green, oolong, and black teas have been well studied, antioxidant activity has not been examined in roasted tea. Therefore, in the current studies, we investigated the antioxidant activity of roasted tea in comparison with those of green, oolong, and black teas.
Eiki, Satoh, Naoki, Tohyama, Masakazu, Nishimura   +2 more
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Moisture Sorption Isotherms of Oolong Tea

Food and Bioprocess Technology, 2008
The sorption isotherms of Oolong tea were determined at temperatures ranging from 5 to 50 °C. Estimated parameters and fitting ability for nine equilibrium relative humidity (ERH) models were evaluated. The modified Oswin equations were found to be an adequate model of three parameters to describe the sorption data.
Chiachung Chen, Yu-Kai Weng
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Antioxidative Activities of Volatile Extracts from Green Tea, Oolong Tea, and Black Tea

Journal of Agricultural and Food Chemistry, 2003
Antioxidative activities of volatile extracts from six teas (one green tea, one oolong tea, one roasted green tea, and three black teas) were investigated using an aldehyde/carboxylic acid assay and a conjugated diene assay. The samples were tested at levels of 20, 50, 100, and 200 micrograms/mL of dichloromethane.
Kenichi, Yanagimoto, Hirotomo, Ochi, Kwang-Geun, Lee, Takayuki, Shibamoto   +3 more
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A rapid quantitative method for polysaccharides in green tea and oolong tea

European Food Research and Technology, 2007
Tea polysaccharides (TPS) from five different kinds of tea contain similar composition of sugars and amino acids. Polysaccharide part of TPS is mainly composed of arabinose, galactose and glucose with the approximate molar ratio of 1:1:0.5. Protein part of TPS is composed of 16 normal amino acids among which Val, Ala, Gly, Glu are the major proportion.
Dongfeng Wang, Xiaoling Zhou, Lei Li, Yangfeng Hou, Jipeng Sun, Jingfeng Wang   +5 more
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Gallic Acid in Old Oolong Tea

2013
Due to the semi-fermentation process, the taste and color of oolong tea are between those of green and black teas. The notation ‘ old oolong tea ’ is used if the oolong tea has been stored for more than five years and refined annually by a drying process in an oven at various temperatures.
Chen, Chung Yu, Lee, Ren Jye, Lee, Viola S Y, Dou, Jianpeng, Preedy, Victor R., Tzen, Jason T C, Lee, Maw Rong   +6 more
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Antimutagenic Activity of Water Extracts of Black Tea and Oolong Tea

Bioscience, Biotechnology, and Biochemistry, 1994
Water extracts of leaves of black tea, oolong tea, and green tea, were examined for antimutagenic activity with Salmonella typhimurium test strains, TA 98 and TA 100. These water extracts significantly decreased the reverse mutation induced by crude dimethyl sulfoxide extracts of grilled beef and, by Trp-P-1, Glu-P-1, and B[a]P in the presence of a rat
Jiro Yamada, Yoshifumi Tomita
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Biotransformation of caffeine in oolong tea by Paecilomyces gunnii

International Biodeterioration & Biodegradation, 2016
Abstract The entomogenous fungus Paecilomyces gunnii was cultured in Chinese oolong tea medium and changes in the chemical composition of this fermented oolong tea are here explored. The alkaloids of this fermented oolong tea were isolated and purified using column chromatography over RP-18, Sephadex LH-20 and silica gel.
Yongbiao Zheng, Xiaoping Xu, Xianwen Zou
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Characterization of the aroma profiles of oolong tea made from three tea cultivars by both GC–MS and GC-IMS

Food Chemistry, 2022
Wilfried Schwab, Chi-Tang Ho, Chuankui Song   +2 more
exaly