Bioactive components of kefir

摘要

Kefir contains a diversity of microorganisms with high content of lactic acid bacteria and yeasts. After fermentation, kefir contains significant amounts of bioactive components. Bioactive peptides from fermented dairy products also provide importanthealth benefits such as improvement in digestive system health, serum cholesterol reduction, improved lactose tolerance, improved immune function, control of irritable bowel symptoms, as well as anticarcinogenic properties. The aim of the study was to determine the effect of fermentation with kefir grains and fermentation with natural kefir starter culture on the antioxidant activity of milk. Total antioxidant activity of kefir samples was analysed using the oxygen radical absorbance capacity (ORAC) assay. ORAC values of kefir obtained using kefir grains were 7.01-7.58 u.mol ml~(-1) TE during storage and those for kefir from natural kefir starter were 5.90-8.95 pmol ml~(-1)TE. All kefir samples had significant antioxidant activity due to the bioactivecomponents formed during kefir fermentation.