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http://dx.doi.org/10.1021/jf902171h

has been cited by the following article:

• TITLE: Determination of Vitamin B12 in Chinese Black Tea Leaves

  AUTHORS: Fei Teng, Tomohiro Bito, Shigeo Takenaka, Yukinori Yabuta, Fumio Watanabe

  KEYWORDS: Chinese Black Tea Leaves, Cobalamin, Ryubao Tea, Vitamin B12

  JOURNAL NAME: Food and Nutrition Sciences, Vol.5 No.14, August 6, 2014

  ABSTRACT: We determined vitamin B12 content of Chinese black tea leaves using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.25 - 0.69 μg/100g dry weight) of vitamin B12 were detected in Pu’er, Fu, and Brick tea leaves. However, vitamin B12 content (0.06 - 1.37 μg/100g dry weight) of Ryubao tea leaves significantly varied. To determine whether Chinese black tea leaves contain vitamin B12 or other corrinoid compounds that are inactive in humans, corrinoid compounds were purified from Ryubao tea by an immunoaffinity column chromatography and vitamin B12 was identified by liquid chromatography-electrospray ionization/tandem mass spectrometry. Vitamin B12 content in the tea drink prepared from Ryubao tea leaves was very low (0.8 ng/100mL). Our results indicate that Chinese black tea is usually not a good source of B12, although Ryubao tea leaves with the highest B12 content may be utilized as a source of this vitamin for vegerarians.