Selenium rich yoghurt [electronic resource]: bio-fortification for better health

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The bioconversion of the sodium selenite Se(IV) to organic form by yoghurt
culture was investigated. The whey-yeast extract media were mixed with 1, 2, 5, 10
and 20 ppm of Se(IV) added as sodium selenite and incubated with yoghurt culture at
40°C for 24 h. Up to 5 ppm of Se, the bacterial growth rate closely resembled that of
the control. However, cells grown in the presence of 10 and 20 ppm of Se(IV) showed
longer lag phase and low growth rates compared to the other treatments. A red colour
of the element Se was accumulated in the bacterial cell cultivated with more than 5
ppm of Se after 24 h of incubation. A dose independent bioconversion rate of selenium
to organic form was observed in the media supernatant. The capability of yoghurt
culture to bioconvert the inorganic Se(IV) to organic form in the culture media was
limited to approximately 1 ppm. The inorganic Se was completely bioconverted in the
cultured media at the level of 1 ppm after 4 h of incubation. The sensory evaluation of
yoghurt supplemented with 0.5 ppm of Se(IV) showed no significant differences
compared to controL In conclusion, the present study stated that yoghurt culture is able
to bio-convert the inorganic Se(IV) to organic form during fermentation process. This
finding could be applied to produce biologically active organic Se fortified yoghurt

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