Effect of bleaching with different clay on the final composition of post-fermentation corn oil with high content of β-sitosterol

Abstract

Bleaching of oils is a stage of refining, and for post-fermentation corn oil, it is a novel issue intended to pretreat the corn oil for downstream refining processes. As a result of the completed research, which used a selection of available bleaching clays at 2 g/100g, post-fermentation corn oil with an improved quality was produced. The oil featured a reduced peroxide number and a lower content of carotenoid dyes. The oil after bleaching was found to have increased oxidation stability without any change discovered in the composition of fatty acids. From this research, it was observed that the 5σ-avenasterol levels were reduced, which affected the total phytosterol content and the reduction of oil colour on the Lovibond scale. The colour strength was considerably reduced by the bleaching process, to a level which varied with the specific bleaching clay. The content of the predominant β-sitosterol did not change significantly and remained at 700 mg/100 g. Optimum processing results were achieved by using the Tonsil 4120 AFF bleaching clay with an addition of activated carbon, and using the Supreme 112FF bleaching clay without activated carbon.