Evaluation of in vitro antioxidant activities of traditional fermented non-alcoholic beverages from Turkey

Abstract

The aim of this study was to evaluate the in vitro potential of different solvent extracts of shalgam juice, hardaliye, boza, ayran (yoghurt drink) and kefir as natural antioxidants. The originality of this study was that different solvents were used for extraction, and according to the extraction yields, total phenolic and flavonoid contents of the extracts and antioxidant activity was determined. Liquid-liquid extraction was applied for sample preparation, which is the preferred extraction technique today due to its simple, fast and efficient procedure to determine antioxidant capacity. The antioxidant capacities of the acetone, ethanol and water extracts of traditional fermented non-alcoholic beverages were estimated using different antioxidant tests, including lipid peroxidation, 1,1-diphenyl-2-picrylhyrazyl (DPPH•) free radical scavenging, superoxide anion radical scavenging, 2,2’-azino-bis(3-ethylbenzothiozoline-6-sulfonic acid) diammonium salt (ABTS•+) cation scavenging activity, hydrogen peroxide scavenging activity and cupric reducing capacity. Results showed that the highest contents of the target components including phenols and flavonoids were found in the water extract. The latter was found to be richer in antioxidant phytochemicals such as phenolics (189.33±2.77 mg PEs/g FW) and flavonoids (321.77±4.03 mg QEs/g FW). This study verified that the water extract with its high level of phenolics and flavonoids can be used as a source of potential antioxidants or functional food materials.