Obtaining butter oil triacylglycerols free from β-carotene and α-tocopherol via activated carbon adsorption and alumina-column chromatography treatments

It is difficult to remove beta-carotene from oils with alumina-column chromatography, because beta-carotene is even less-polar than triacylglycerols (TAGs) are. The objective of this study was to obtain butter oil TAGs free from beta-carotene and antioxidants via sequential treatments with activated carbon (AC) adsorption and alumina column chromatography. The AC used was prepared from waste apricots. The effects of AC dosages, temperatures and time courses on beta-carotene adsorption were studied. The Langmuir and Freundlich isotherms were used to describe the adsorption of beta-carotene onto AC, and it was found to be more consistent with the Freundlich isotherm with a higher R-2 value (0.9784). Adsorption kinetics of beta-carotene was analyzed by pseudo-first order and pseudo-second order models. The pseudo-second order model was found to explain the kinetics of beta-carotene adsorption more effectively (R-2 = 0.9882). The highest beta-carotene reduction was achieved (from 31.9 to 1.84 mg/kg) at an AC dosage of 10 wt%, temperature of 50 degrees C, and adsorption time of 240 min. A considerable amount of alpha-tocopherol was also adsorbed during the AC treatment. Remaining portions of alpha-tocopherol were completely removed with alumina adsorption chromatography. The method described may be used for purification of vegetable oil TAGs, which will be used as model compounds in model oxidation studies.