**7. Other purification techniques**

There has been also limited literature reported on the following alternative methods for purification of tocopherols and sterols from SODD. Hence, Nagesha and coworkers (Nagesha, G. *et al.*, 2003) using nonporous denser polymeric membranes to separate tocopherols from SODD by permeation. The separation in a denser membrane is generally based on a solution-diffusion mechanism. The lower polarity of tocopherols compared to that of free fatty acids appears to have facilitated the preferential permeation of tocopherols through the hydrophobic membrane. Selectivity of the membrane for tocopherols improved with esterified SODD, because the presence of FAME decreased the viscosity of the feed and thereby increased convective flow, which in turn improved permeate flux.

Alternatively, Maza and coworkers (Maza, 1992) concentrated tocopherols and sterols by addition of melted deodorizer distillates to a solution of urea and alcohol which separate fatty acids from the mixture.

In addition, Gunawan and coworkers (Gunawan *et al.*, 2008a) proposed a facile procedure to isolate naturally occurring FASEs from SODD without degradation of FASEs. SODD was first subjected to a modified soxhlet extraction (MSE) to enrich FASEs in a non polar lipid fraction (NPLF). Modified silica gel column chromatography (MSE) was then applied to NPLF to collect FASEs in a third fraction with a purity of 79.99 wt% and a recovery of 97.38%. The third fraction was then subjected to a binary solvent (water/acetone = 20/80, v/v) extraction to purify FASEs to a purity of 86.74 wt% with a total recovery of 85.32%.

solvent-to-feed ratio of 35, the phytosterol esters were concentrated in the raffinate up to

Other supercritical fluids have been explored but unsuccessfully for the separation of different pairs of components. An attempt at using similar methodology to (Mendes, 2000) and (Mendes, 2005) but using liquid gas petroleum instead of carbon dioxide did not change the poor concentration factor between the critical pairs of components (Buczenko *et al.*, 2003). Buczenko and coworkers (Buczenko, 2003) performed the saponification of the raw

As discussed above, there are a lot of experimental studies proving the efficiency of the supercritical extraction to concentrate the vitamin E from different raw material or in some cases, from synthetic mixtures representing the deodorizer distillate, but the extraction of sterols using supercritical fluid from the deodorizer distillate was not described in the

On the other hand, due to the low content of squalene in SODD, specific extraction processes of squalene using supercritical fluid from SODD was not described in the literature. Existing studies are models of fractionation of artificial mixtures such as those mentioned above (Chang, 2000). For example, Brunner (Brunner, 1994a) studied the phase equilibrium for recovering α-tocopherol from a mixture of squalene, tocopherol, and campesterol. He concluded that the separation factor for squalene/α-tocopherol varied between a value of 4 at low squalene concentrations (0.5 wt %), to a value of 1 at high squalene concentrations (85 wt %), at pressures ranging from 200 to 300 bar and

Bondioli and coworkers (Bondioli *et al.*, 1993) esterified FFAs into their corresponding glycerides and then applied a supercritical carbon dioxide extraction to produce a squaleneenriched fraction (purity 90.0%, yield 91.1%), but from olive oil deodorizer distillates.

There has been also limited literature reported on the following alternative methods for purification of tocopherols and sterols from SODD. Hence, Nagesha and coworkers (Nagesha, G. *et al.*, 2003) using nonporous denser polymeric membranes to separate tocopherols from SODD by permeation. The separation in a denser membrane is generally based on a solution-diffusion mechanism. The lower polarity of tocopherols compared to that of free fatty acids appears to have facilitated the preferential permeation of tocopherols through the hydrophobic membrane. Selectivity of the membrane for tocopherols improved with esterified SODD, because the presence of FAME decreased the viscosity of the feed and

Alternatively, Maza and coworkers (Maza, 1992) concentrated tocopherols and sterols by addition of melted deodorizer distillates to a solution of urea and alcohol which separate

In addition, Gunawan and coworkers (Gunawan *et al.*, 2008a) proposed a facile procedure to isolate naturally occurring FASEs from SODD without degradation of FASEs. SODD was first subjected to a modified soxhlet extraction (MSE) to enrich FASEs in a non polar lipid fraction (NPLF). Modified silica gel column chromatography (MSE) was then applied to NPLF to collect FASEs in a third fraction with a purity of 79.99 wt% and a recovery of 97.38%. The third fraction was then subjected to a binary solvent (water/acetone = 20/80, v/v) extraction to purify FASEs to a purity of 86.74 wt% with a total recovery of 85.32%.

thereby increased convective flow, which in turn improved permeate flux.

material and the extraction of unsaponifiable matter as pre-treatment of VODD.

82.4 wt-% with satisfactory yield (72%).

temperatures ranging from 70 to 100 ºC.

**7. Other purification techniques** 

fatty acids from the mixture.

literature.

These methods do not present a significant advance regarding the most frequently utilized methods and probably their application to production scale would be little profitable. However, they can be used to isolate tocopherols and sterols from SODD at laboratory scale or complement other methods at industrial scale.
