Format

Send to

Choose Destination
See comment in PubMed Commons below
J Photochem Photobiol B. 2013 Nov 5;128:43-9. doi: 10.1016/j.jphotobiol.2013.07.021. Epub 2013 Aug 20.

The effect of milk alpha-casein on the antioxidant activity of tea polyphenols.

Author information

1
Groupe de recherche en Biologie Végétale, Département de Chimie-Physique, Université du Québec à Trois-Rivières, C.P. 500, Trois-Rivières, Québec G9A 5H7, Canada.

Abstract

In this study, we report how the antioxidant capacities of major tea polyphenols are affected by their interactions with milk alpha-casein (milk protein) using three complimentary oxidation methods: ABTS(+) radical cation scavenging, cyclic voltammetry and lipid peroxidation inhibition. We found that using the ABTS(+) assays, the antioxidant activity of all polyphenols was lowered by 11-27% in the presence of caseins. Using cyclic voltammetry, the overall current measured at the electrode was decreased by the presence of the protein, from 21% to 61%. The peak potentials were also shifted to higher values varying from 13 to 41 mV. However, using lipid peroxidation method, we noticed of the antioxidant activity of all the polyphenols changed (from 6% up to 75%) after the addition of alpha-casein. The results show using this method the larger gallate esters containing polyphenols epicatechingallate (ECG) and (epigallocatechingallate (EGCG) were less affected by the presence of casein than smaller polyphenols catechins (C), epicatechin (EC) and epicgallocatechine (EGC). Alpha-casein caused a small effect on the chain breaking antioxidant capacity of theaflavins as well. Therefore, casein has different effects on the overall antioxidant capacities of tea compounds depending on the methods used. We aim to understand those results with the types of protein-polyphenol interactions that take place in various settings and their effects on the antioxidant capacities of those compounds.

KEYWORDS:

Casein; Cyclic voltammetry; Linoleic acid; Milk; Polyphenol; Tea

[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center