Voltammetric Evaluation of Polyphenol–Protein Interactions and Their Influence on the Antioxidant Capacity of Tea

Autor: Herman Budnikov, Guzel Ziyatdinova, Ekaterina Guss
Rok vydání: 2020
Předmět:
Zdroj: Journal of Analytical Chemistry. 75:685-690
ISSN: 1608-3199
1061-9348
DOI: 10.1134/s1061934820050202
Popis: A voltammetric method for evaluating polyphenol–protein interactions was developed based on the oxidation of polyphenols at an electrode modified with multi-walled carbon nanotubes and electropolymerized quercetin. Tea polyphenols (catechin and epigallocatechin gallate) and milk proteins (casein, bovine serum albumin, and β-lactoglobulin) were considered as model systems. It was found that proteins bind the test polyphenols (from 10 to 60%) with increasing protein content (from 1 : 0.25 to 1 : 1.5, by volume) in the mixture by decreasing the fraction of free polyphenol. The developed approach was used to assess the effect of milk on the antioxidant properties of tea (green, white, oolong, and black teas), which were expressed through the antioxidant capacity (AOC) parameter. A statistically significant decrease in the AOC of tea by a factor of 1.8–23 in the presence of 20 vol % milk was demonstrated.
Databáze: OpenAIRE
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