CEM KARAGOZLU*, GULFEM UNAL, A. SIBEL AKALIN, ECEM AKAN, OZER KINIK
* Corresponding Author 
Ege University, Faculty of Agriculture, Department of Dairy Technology,
35100 Bornova, Izmir, Turkey

Abstract

The effects of supplementation with green and black tea on chemical and sensory properties and antioxidant activities of kefir were investigated during 21 days of storage. pH and titrable acidity values were within acceptable levels during 21 days of storage. Total dry matter, fat and lactic acid contents of all samples were in accordance with Turkish Food Codex. The samples containing green tea extract had the highest DPPH• scavenging activity compared to those of supplemented with black tea extract throughout the storage. Green tea had a superior effect compared to black tea in terms of total phenolic content of kefir samples. Statistical differences change between parameters kefir samples. CK (control) group received higher scores compared to those in black and green tea groups and they were also appreciated by the panelists during storage. All kefir samples with added black or green tea showed acceptable sensory scores

INTRODUCTION

Kefir is an acidic and mildly alcoholic fermented milk product that is believed to contain many functional substances, and it has been postulated that the longevity of Balkans, Eastern Europe and Caucasus people are partially due to their frequent consumption of fermented milk. Kefir and its exopolysaccharide, kefiran have proved to have antimicrobial activities. Both have been reported to exhibit significant antibiotic activity against both Gram-positive and Gram-negative bacteria (1, 2). Tea (Camellia sinensis, family Theaceae) is consumed worldwide and is second only to water in its popularity as a beverage. Many health benefits have been ascribed to consumption of this beverage, including the effects on reduction of cholesterol, protection against cardio-vascular diseases and cancer. All beneficial effects of tea have been attributed to the strong antioxidative activity of phenolic compounds found in tea, known as tea catechins (3, 4). Kefir has an increasing market share worldwide and also there are many scientific studies focused on its nutritional and health effects. In this study; the effects of addition of black and green tea, at diffe ...