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.