Trolox

Journal of Food Composition and Analysis 24 (2011) 79–86

Contents lists available at ScienceDirect

Journal of Food Composition and Analysis
journal homepage: www.elsevier.com/locate/jfca

Original Article

The influence of domestic culinary processes on the Trolox Equivalent Antioxidant
Capacity of green tea infusions
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C. Samaniego-Sanchez, Y. Inurreta-Salinas, J.J. Quesada-Granados*, R. Blanca-Herrera,
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M. Villalon-Mir, H. Lopez-Garcıa de la Serrana, M.C. Lopez Martınez
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Dpto. Nutricio y Bromatologı´a, Facultad de Farmacia, Universidad de Granada, Campus de Cartuja s/n, 18071 Granada. Spain

ARTICLE INFO

ABSTRACT

Article history:
Received 24 June 2009
Received in revised form 14 June 2010
Accepted 17 June 2010
Available online 8 January 2011This paper presents an investigation into the influence of several culinary factors, such as water
temperature, infusion time, stirring and dosage form, on polyphenol content and antioxidant capacity
(TEAC values) during the domestic preparation of green tea. The results obtained show that water
temperature and infusion time strongly influence total polyphenol levels and the antioxidantcapacity of
green tea. Temperatures of 70–80 8C together with infusion times of 3–5 min produced greatest effect, in
this respect. At 90 8C, extraction was faster and more effective. However, prolonged infusion at this
temperature may cause a loss of polyphenol compounds and, consequently, of antioxidant capacity.
Factors such as agitation and dosage form do not seem to have much influence.Furthermore, it was
found that pure green tea infusions have higher antioxidant properties than do blends of green tea with
aromatic herbs and fruits.
ß 2010 Elsevier Inc. All rights reserved.

Keywords:
Green tea
Antioxidant capacity
2,20 -Azinobis-(3-ethylbensothiazoline)-6sulfonic acid
Phenol compounds
TEAC
ABTS
Food analysis
Food composition

1. Introduction
A culinary process is anyprocess required to transform food
ingredients in an appropriate way into prepared dishes suitable for
human consumption (Bello, 1998). According to this definition, the
process of preparing tea infusions can be said to be a culinary
process.
Tea is the extract of the plant Camellia sinensis and the second
most consumed beverage in the world (Costa et al., 2002). On the
basis of itsmanufacturing process, tea can be classified into three
types: (a) unfermented green tea (obtained by drying and pressing
dry tea leaves, with no fermentation process being performed); (b)
semi-fermented oolong tea (produced by partly fermenting fresh
green tea leaves before they dry); (c) fermented red and black tea
(dried after fermentation) (Zuo et al., 2002).
Unfermented green tea has the highestantioxidant capacity,
since the polyphenol levels of both fermented and semi-fermented

Abbreviations: ABTS, 2,20 -azinobis-(3-ethylbensothiazoline)-6-sulfonic acid; DPPH,
1,1-diphenyl-2-picrylhydrazyl; HCA, hierarchical cluster analysis; LSD, Fisher’s
least significant difference; TEAC, Trolox Equivalent Antioxidant Capacity (Trolox,
6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid);TPC, total polyphenol
content.
* Corresponding author. Tel.: +34 958 24 06 69; fax: +34 958 24 95 77.
E-mail address: quesadag@ugr.es (J.J. Quesada-Granados).
0889-1575/$ – see front matter ß 2010 Elsevier Inc. All rights reserved.
doi:10.1016/j.jfca.2010.06.003

tea decrease during the production process (Joubert et al., 2008;
Vertuani et al., 2004; Seeram et al., 2008).
An increasingnumber of consumers are expressing interest in
the beneficial effects of green tea, resulting from the high
polyphenol levels contained and the consequent antioxidant
activity it can stimulate. However, several factors related to its
production and preparation may cause a significant variation in the
polyphenol content.
The green tea plant is commonly grown in India, China, Japan,
Taiwan, Sri...