Determination of antimutagenic properties of acetone extracted fermented milks and changes in their total fatty acid profiles including conjugated linoleic acids

Abstract

Kefir has a unique microbial content that results in complex fermented milk drink. In this study, the antimutagenic power of acetone‐extracted kefir was determined and compared to acetone‐extracted yogurt and milk using different chemical mutagens in the Ames Salmonella microsomal test. Acetone extracts were fat portions of the kefir, yogurt and milk samples. The direct‐acting mutagenic agents methylmethanosulphate (MMS) and sodium azide (SA), and the indirect‐acting mutagenic agents aflatoxin B1 (AFB1), 2‐aminoanthracene (2AA), and 3,2‐dimethyl‐4‐aminobiphenyl (DMAB) were used in Ames test with TA 100 Salmonella typhimurium . Acetone‐extracted fermented milk samples significantly inhibited mutagenicity for different percentages of MMS, SA, AFB1 and 2‐AA. Results indicate that milk also had a lower antimutagenic effect. Additionally, the fatty acid profiles of milk, yogurt and kefir were determined. A two‐step methylation method followed by gas chromatography was used to identify conjugated linoleic acids (CLA). Fermentation slightly affected fatty acid composition. Three isomers of CLA (c9, t11; t10, c12; t9, t11), butyric, palmitic, palmitoleic, oleic acids, which have been proven as antimutagenic components of milk fat, were in higher concentrations in kefir.