[A method of quantitative determination of delta 5,7-sterols in unsaponifiable lipid fractions].

The technique is offer for rapid quantitative definition of sterols having a system of delta 5,7-conjugated double bonds which conditions biological activity of D vitamin--the result of photoisomerisation of the sterols. The technique bases on the analysis of UV absorption spectra of unsaponifiable lipid fraction of several kinds of mutant yeast strains and the model mixtures of sterols. The results obtained concerning the estimation of delta 5,7-sterols containing in total fraction are confirmed by gas-liquid-chromatography and mass-spectrometry data.