Previous reports showed that vitamin E in palm oil consists of various isomers of tocopherols and tocotrienols [alpha-tocopherol (alpha-T), alpha-tocotrienol, gamma-tocopherol, gamma-tocotrienol, and delta-tocotrienol), and this is normally analyzed using silica column HPLC with fluorescence detection. In this study, an HPLC-fluorescence method using a C30 silica stationary phase was developed to separate and analyze the vitamin E isomers present in palm oil. In addition, an alpha-tocomonoenol (alpha-T1) isomer was quantified and characterized by MS and NMR. (alpha-T1 constitutes about 3-4% (40+/-5 ppm) of vitamin E in crude palm oil (CPO) and is found in the phytonutrient concentrate (350+/-10 ppm) from palm oil, whereas its concentration in palm fiber oil (PFO) is about 11% (430+/-6 ppm). The relative content of each individual vitamin E isomer before and after interesterification/transesterification of CPO to CPO methyl esters, followed by vacuum distillation of CPO methyl esters to yield the residue, remained the same except for alpha-T and gamma-T3. Whereas alpha-T constitutes about 36% of the total vitamin E in CPO, it is present at a level of 10% in the phytonutrient concentrate. On the other hand, the composition of gamma-T3 increases from 31% in CPO to 60% in the phytonutrient concentrate. Vitamin is present at 1160+/-43 ppm, and its concentrations in PFO and the phytonutrient concentrate are 4,040+/-41 and 13,780+/-65 ppm, respectively. The separation and quantification of alpha-T1 in palm oil will lead to more in-depth knowledge of the occurrence of vitamin E in palm oil.

The application of supercritical fluid chromatography (SFC) coupled with a UV variable-wavelength detector to isolate the minor components (carotenes, vitamin E, sterols, and squalene) in crude palm oil (CPO) and the residual oil from palm-pressed fiber is reported. SFC is a good technique for the isolation and analysis of these compounds from the sources mentioned. The carotenes, vitamin E, sterols, and squalene were isolated in less than 20 min. The individual vitamin E isomers present in palm oil were also isolated into their respective components, alpha-tocopherol, alpha-tocotrienol, gamma-tocopherol, gamma-tocotrienol, and delta-tocotrienol. Calibration of all the minor components of palm as well as the individual components of palm vitamin E was carried out and was found to be comparable to those analyzed by other established analytical methods.

The qualities of oils extracted from fresh and dried palm-pressed mesocarp fiber were evaluated. The means of extraction included conventional solvent extraction and supercritical carbon dioxide (SC-CO 2 ) extraction with and without addition of ethanol. Extraction efficiency using pure SC-CO 2 and the effect of moisture content on efficiency were studied. Minor components, such as vitamin E, carotenoids, squalene and phytosterols, obtained by different methods were compared. The quality of oil recovered from fresh palm-pressed fiber is generally better than that of oil recovered from dried fiber. The SC-CO 2 extraction rate was lower for fresh fiber than for dried fiber. The incorporation of ethanol with SC-CO 2 resulted in oil with higher oxidative stability than did SC-CO 2 alone. Concentrations of minor components and the acylglycerol compositions of the oils extracted from both types of fibers were similar. SCHEME 1 FIG. 1. Effect of CO 2 flow rate on the extraction of residual oil from dried palm-pressed fiber using supercritical CO 2 (SC-CO2) and n-hexane.

This study reports the effect of physical refining on palm vitamin E including α tocopherol, α-, Γ- and δ- tocotrienols as well as δ-tocomonoenol. A method using HPLC with fluorescence detector using normal phase silica column is described. An isocratic elution with n-hexane/THF/2-propanol (1000:60:4, by vol.) as mobile phase was used. The structure of the α- tocomonoenol was determined using gas chromatography coupled with mass spectrometry. The composition of the vitamers were α-tocopherol (14–17%), ß-tocotrienol (22–24%), Γ-tocotrienol (49–53%), δ-tocotrienol (6–7%) and α-tocomonoenol (3%) throughout the physical refining. The concentration of all vitamers in crude palm oil was 1273±18 ppm. The concentrations of all vitamers in degummed palm oil, bleached palm oil and deodorized palm oil were 1134±20 ppm, 1095±18 ppm and 1029±18 ppm, respectively. This method provides fast and valuable information with minimal analysis time and no sample pre-treatment

Supercritical carbon dioxide (SC‐CO2) was used to extract palm oil from palm mesocarp (Elaeis guineensis). The conditions surveyed were 40 to 80C and 14 to 30 MPa. The free fatty acid content in SC‐CO2 extracted palm oil was found to be 0.61% as compared to 3.15% in commercial crude palm oil (CPO). The average peroxide value of the SC‐CO2 extracted CPO was 1.68 meq O2/kg, which indicated that SC‐CO2 extraction does not induce the formation of undesirable peroxides and hydroperoxides. The deterioration of bleachability index of SC‐CO2 extracted palm oil met the specification of fairly good CPO with average value of 2.60. The oxidative stability of SC‐CO2 extracted palm oil was slightly lower than commercial and n‐hexane extracted CPO. The pro‐oxidants such as iron and copper were significantly reduced in the SC‐CO2‐produced oil. Minor components such as carotenes, vitamin E (e.g., tocopherols and tocotrienols), phytosterols and squalene were co‐extracted during the SC‐CO2 extraction. The overall quality of SC‐CO2 extracted CPO appears equivalent to those obtained by commercial processing of CPO.

Palm-pressed fiber, a by-product of palm oil milling, was extracted successively with hexane and 95% ethanol; the ethanol extracts yielded 46,800 ppm of phospholipids. The phospholipid composition, as analyzed by HPLC coupled with an ELSD, was found to be predominantly PC, PE, phosphatidylglycerol, and PA; as expected, the FA were more unsaturated than the TAG. Palm-pressed fiber is estimated to be able to provide 21,645 tonnes of palm lecithin based on the present total world production of fresh fruit bunches and thus be an alternative source of lecithin, which is normally obtained from soybeans.

Successful separation of triglycerides, diglycerides, free fatty acids, carotenes, tocopherol, and tocotrienols from crude palm oil has been achieved by supercritical fluid chromatography (SFC) with a combination of a C18 and a silica gel column. The separation was carried out by the programmed extraction elution method. Free fatty acids were separated into five components by gas‐liquid chromatography; tocopherol and tocotrienols were also separated into four components by SFC analysis, and the pure fractionated carotenes were obtained by preparative SFC. Thus, by using supercritical fluid chromatography, crude palm oil components can be separated and fractionated, based on differences in their functional groups.

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