Exploring the relation between composition of extracts of healthy foods and their antioxidant capacities determined by electrochemical and spectrophotometrical methods

Gonzalez-Rodriguez, Jose and Rivas Romero, Pilar and Estevez Brito, Rafael and Rodriguez Mellado, Jose MIguel and Ruiz Montolla, mercedes and Rodriguez Amaro, Rafael (2018) Exploring the relation between composition of extracts of healthy foods and their antioxidant capacities determined by electrochemical and spectrophotometrical methods. LWT - Food Science and Technology . ISSN 0023-6438

Full content URL: https://doi.org/10.1016/j.lwt.2018.04.079

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Exploring the relation between composition of extracts of healthy foods and their antioxidant capacities determined by electrochemical and spectrophotometrical methods

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Abstract

The composition of the methanolic and aqueous extracts of teas (White, Black, Red, Green and Mix 3 teas) and
infusions (Chamomile, Pennyroyal mint, Rooibos, Sage and Linden) was studied by Gas Chromatography coupled
with Mass Spectroscopy (GC-MS) and High Performance Liquid Chromatography (HPLC). To solve the
problems encountered in GC-MS with flash-points and boiling points, external standards were used in HPLC.
The antioxidant capacity of the extracts (in trolox equivalents) was measured by using the DPPH radical
scavenging assay, CUPRAC assay and two electrochemical methods implying radicals generated from hydrogen
peroxide on Hg and glassy carbon electrodes covered with Pt nanoparticles and poly-neutral red (PNR-Pt). There
are good correlations between the antioxidant capacities measured by the two electrochemical techniques and
also between such techniques and CUPRAC, but the DPPH radical scavenging assay measures different type of
antioxidant activity than the rest. The relation between antioxidant capacity and composition from the viewpoint
of concentration and individual antioxidant capacity of each component is discussed. The main conclusion
indicates that the total content of antioxidants of an extract is not bi-univocally related to its antioxidant capacity,
because the distinct components of the extracts can have very different antioxidant capacities.

Keywords:antioxidants, food extracts, healthy foods, tea, herbs, CUPRAC, DPPH
Subjects:D Veterinary Sciences, Agriculture and related subjects > D610 Food Science
F Physical Sciences > F100 Chemistry
F Physical Sciences > F180 Analytical Chemistry
F Physical Sciences > F110 Applied Chemistry
F Physical Sciences > F170 Physical Chemistry
Divisions:College of Science > School of Chemistry
ID Code:32549
Deposited On:03 Jul 2018 07:46

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