Decrease in the Antioxidant Capacity in Beverages Containing Tea Extracts during Storage

Tomas Nekvapil,Vladimir Boudny,Petr Dvorak,Martin Hostovsky,Ladislav Malota,Vladimir Kopriva

doi:10.1100/2012/361698

Tomas Nekvapil, Vladimir Boudny + Show 4 more

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https://doi.org/10.1100/2012/361698

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Abstract

The aim of this work was to determine antioxidant capacity of beverages containing black, white, and green tea extracts using the photochemiluminescence method, and to monitor its changes based on the storage temperature and time. Samples were stored at two different temperatures (refrigerated at 4°C and laboratory temperature 22°C), analyzed after opening of the original package, and consequently after 4 and 7 days. Results of the antioxidant capacity are expressed as the standard equivalents, that is, ascorbic acid in mmol/L. The highest mean value of the antioxidant capacity was found after opening of the original package in fruit-juice-enriched samples and totaled 9.793 mmol/L. This group revealed significant dependence (P < 0.05) not only on the storage time, but also temperature. In samples without added fruit juices containing preservatives the value was 0.428 mmol/L. This group showed significant dependence (P < 0.05) on the decrease of antioxidant capacity only when based on the storage time. Samples without fruit juices or preservatives showed significant decrease in the antioxidant capacity (P < 0.05) after 4 days of storage based on the storage time. The dependence on temperature was revealed only after 7 days of storage.

Highlights

Antioxidant capacity is an overall ability of organisms or food to catch free radicals and prevent their harmful effect
The aim of our work was to determine antioxidant capacity of beverages containing tea extracts using the photochemiluminescence method (PCL), and to assess its changes during their storage based on the temperature and storage time
Results imply the positive impact of adding fruit juices on the antioxidant capacity of beverages containing white, black, and green tea extracts

Summary

Introduction

Antioxidant capacity is an overall ability of organisms or food to catch free radicals and prevent their harmful effect. Antioxidative effect includes protection of cells and cellular structures against harmful effect of free radicals, especially oxygen and nitrogen. Substances with antioxidative properties are called antioxidants. They are contained in food and food supplements, most commonly in fruits, vegetables, rice, wine, meat, eggs, and other foodstuff of plant and animal origin. Antioxidative, that is, favorable effect of selected antioxidants, was studied in vivo by, for example, Terziev et al [1], Nguyen-Deroche et al [2] and Meira deFaria et al [3], and in vitro by Gondoin et al [4]

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