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Chemical Forms of Iron, Calcium, Magnesium and Zinc in Black, Oolong, Green and Instant Black Tea
Author(s) -
JACKSON LAUREN S.,
LEE KEN
Publication year - 1988
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1988.tb10204.x
Subject(s) - chemistry , food science , polyphenol , calcium , magnesium , black tea , zinc , green tea , catechin , biochemistry , antioxidant , organic chemistry
The chemical forms of iron, calcium, magnesium and zinc were quantified in black, oolong, green and instant black tea infusions. Iron was least soluble in black tea (69%) and most soluble in instant black tea (100%). Calcium was least soluble in green tea (46%) and instant black tea (35%). Almost all magnesium and zinc (89%‐98%) were soluble in all teas. The fermented teas had more complexed iron than unfermented tea. Conversely, more ionic iron was in green tea. All ionic iron in the four teas was in the ferric state. Tannase, a polyphenol degrading enzyme, and lemon juice solubilized iron and calcium in some teas. Tannase and lemon juice might reduce the detrimental effect of tea on mineral availability.