Separation of tocopherol succinates from deodorizer distillate

Isolation of tocopherol succinates from sterol-removed, succinated deodorizer distillate (DOD) mixture by crystallization was investigated. Membrane technology was also evaluated for its effectiveness to separate tocopherol succinates from mixtures containing sterols and tocopherols. Crystallization was conducted at -20C for 24 h with different solvents, including hexane, petroleum ether, and a mixture of acetone and methanol (4:1, v/v). The crystallization results showed that recovery of tocopherol succinates from the cake fraction was poor with all solvents tested, with less than 10% of original tocopherol succinates in the raw material being crystallized under conditions employed. Among the solvents tested, hexane was better for the recovery of nona-tocopherol succinates in the cake fraction. Furthermore, a high proportion of free fatty acids (FFA) was co-crystallized along with tocopherol succinates for all solvents used, leading to tocopherol succinates contents in the cake fractions lower than that in the raw material. Two nanofiltration membranes (DS-7 and AP01) were also examined using hexane or petroleum ether as a solvent. The recovery of tocopherol succinates was over 60%. However, their concentration was increased only by 6%. A combined process was then evaluated that included crystallization before succinylation, succinylation, first stage membrane separation, and second stage membrane separation. ne final tocopherols concentration derived from this combined process was twice as much as that of the original DOD.