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Effects of potassium and magnesium nutrition on the quality components of different types of tea
Author(s) -
Ruan Jianyun,
Wu Xun,
Härdter Rolf
Publication year - 1999
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199901)79:1<47::aid-jsfa172>3.0.co;2-a
Subject(s) - polyphenol , chemistry , black tea , potassium , food science , magnesium , flavour , caffeine , theaflavin , green tea , nutrient , antioxidant , biology , biochemistry , organic chemistry , endocrinology
Abstract In field experiments, the effects of potassium and magnesium nutrition on the quality components of different types of tea, including black tea, oolong tea and green tea, were studied. The results show that K and Mg fertilizer application increased the contents of free amino acids and caffeine of the various tea types with the maximum increase found in the treatment including both nutrients. The content of polyphenols in tea leaves was also increased by K application. The effect of Mg on polyphenol content was inconsistent. In general, Mg apparently decreased the content of polyphenols and only in case the soils were depleted of plant available K and Mg, a slight increase could be observed. The contents of theaflavins and thearubigins, important quality components of brewed black tea, were also increased by K application. Flavour compounds in brewed oolong tea were considerably improved by K and Mg application. © 1999 Society of Chemical Industry