Separating Tocotrienols from Palm Oil by Molecular Distillation

Abstract

Crude palm oil contains approximately 1% minor components, including carotenoids and vitamin E (tocopherols and tocotrienols), which contribute to the stability and nutritional properties of palm oil. Palm oil is considered one of the best sources of vitamin E. The vitamin E content in palm oil is unique because it is composed of tocotrienols rather than tocopherols. Palm fatty acid distillate (PFAD) is the volatile organic material recovered as a valuable by-product in the deodorization of palm oil. Several processes have been proposed for recovering tocopherols and tocotrienols from PFAD. For this separation process, it is necessary to develop a processing procedure to extract the valuable tocotrienols and other minor components from PFAD using molecular distillation. Molecular distillation occurs at low temperatures and reduces the problem of thermal decomposition. High vacuum also eliminates oxidation that might occur in the presence of air. The rate of evaporation is controlled by the rate at which the molecules escape from the free surface of the liquid and condense on the condenser. The effects of feed-flow rate and temperature of distillation on extraction of minor components from PFAD are based on concentrations, distribution coefficients, and relative volatilities. The separation of tocotrienols from PFAD approached maximum values at low temperatures and fell drastically as temperature increased. For the optimum conditions for the extraction of tocotrienols with high yield and purity, it is necessary to determine the effect of processing variables on the extraction of minor components (i.e., tocotrienols, α-tocopherol) from the PFAD in terms of concentrations in the liquid and vapor phases, to reveal the behavior of target components in the evaporation process, and to determine the evaporation and volatility properties of tocotrienols and other minor components from PFAD.