In this study, the percentage content of free steroid in oils, fats and biodiesel was analyzed. For this, the saponification reaction on a microscale was used, and this procedure for extraction of unsaponifiable fraction was studied in several experimental steps. After the process of saponification, the unsaponifiable fraction was analyzed by gas chromatography with flame ionization detector, where all steroids present in each oil, fat and biodiesel were identified and their contents determined and compared to their respective biodiesel. A reduction in unsaponifiable fraction of each oil and fat and its biodiesel was noted, as well as a reduction in the content of free steroids. The results showed that, compared to the sedimentation problem of steroids in biodiesel, some raw materials, such as chicken fat and babassu oil may be promising because they have low content and high reduction percentages of steroids when converted to biodiesel.
unsaponifiable fraction; free steroids; gas chromatography
