Extraction of Carotenes from Palm Oil. I.

Abstract

The extraction of carotenes from crude palm oil pretreated with phosphoric acid carried out using various adsorbents. Adsorption experiments were conducted at 50°C for 1 h using 20.0 g of the oil and 13 g of an adsorbent. Alumina, silica gel, activated clay (abbreviated as clay), alumina gel-clay and silica gel-clay of various mixing ratio (1 : 11 : 4) were used as the adsorbents. Adsorbed carotenes were released by a 20% acetic acid heptane solution at 80°C for 30 min. Carotene content was determined as β-carotene by spectrophotometry. The amount of adsorbed carotene per unit weight of adsorbent was greatest (ca. 3.5 mg/g adsorbent) in the case of clay and became progressively less in the order of silica gel-clay and alumina gel-clay. An increase in the mixing ratio of clay favored carotene adsorption in all cases. No carotene was adsorbed on either alumina or silica gel. In the case of alumina gel-clay, carotene recovery based on the amount of adsorbed carotene increased with decrease in the mixing ratio of clay. The highest value was 41%. In the case of silica gel-clay, no relationship could be detected between carotene recovery and the mixing ratio. Carotene recovery was ca. 7% in all cases. Carotene adsorbed on the clay could not be released under the present experimental conditions. Replacement of heptane with ethanol in the releasing system enhanced the recovery of carotene adsorbed on alumina gel-clay and silica gel-clay but both chloroform and benzene when used instead failed to do so. When acetic acid was substituted by KOH ethanol solution, benzene was effective for recovery of the carotene adsorbed on alumina gel-clay. Modification of the present releasing system did not improve the recovery of carotene adsorbed on the clay. X-ray diffraction patterns of the adsorbents changed according to the adsorption procedure used.