TY  - JOUR
AB  - Purpose– The purpose of this paper was to determine total polyphenols (TP), total flavonoids (TF) and (-)-epigallocatechin gallate (EGCG) in five commercial tea extracts and in their infusions at various temperatures (95-60°C) and brewing times (5-30 min). Design/methodology/approach– TP was determined by the Folin–Ciocalteu method, TF by the aluminium chloride colorimetric method and EGCG by HPLC method. Findings– The results showed that White tea – Silver needle had the highest content of TP and EGCG when extracted, but its infusions had very poor concentrations of these compounds. Green tea infusion was better source of TP and EGCG than white or black tea, although its extract did not contain a very high amount of TP compared to the latter two types. Black tea extract had a relatively high content of TP and TF in its extract. Its infusions as well contained higher concentrations of TP than white tea, but lower concentrations of EGCG than all studied teas. Originality/value– Increasing infusion time and temperature does not necessarily increase the concentration, according to the results. To the authors’ knowledge, this is the first report on comparing these types of tea, especially the white tea, with other well-known teas under various infusion conditions. The extraction of the white tea leaves was also not found in previous works.
VL  - 44
IS  - 5
SN  - 0034-6659
DO  - 10.1108/NFS-10-2013-0119
UR  - https://doi.org/10.1108/NFS-10-2013-0119
AU  - AlHafez Maysoon
AU  - Kheder Fadi
AU  - AlJoubbeh Malak
PY  - 2014
Y1  - 2014/01/01
TI  - Polyphenols, flavonoids and (-)-epigallocatechin gallate in tea leaves and in their infusions under various conditions
T2  - Nutrition & Food Science
PB  - Emerald Group Publishing Limited
SP  - 455
EP  - 463
Y2  - 2024/04/19
ER  -