Laboratory Studies on Membrane Deoiling of Lecithin

Deoiling of lecithin using a nonporous membrane
was examined in a favorable solvent (hexane)
medium with soy and rice bran lecithins. During the
membrane process, the acetone insoluble (AI) content of
soy lecithin increased from 63.2 to 81.0% in a single step
batch operation. The membrane exhibited an excellent
selectivity since phospholipid (PL) reverse micelles formed
in the system were rejected almost completely due to low
solubility probably aided synergistically by size exclusion.
Diafiltration achieved greater oil removal from lecithin as
reflected in terms of higher AI and PL contents in the deoiled
lecithin. In discontinuous diafiltration, the PL content
increased from 33.3 to 85.5% in rice bran lecithin (150%
dilution to feed) and 56.6 to 85.7% in soy lecithin (200%
dilution), respectively. The simulated continuous diafiltration
run showed slightly greater PL content in soy lecithin
(91.3%) compared to discontinuous diafiltration (89.7%)
besides offering higher productivity. The membrane
showed a color reduction of*60% in soy lecithin but there
was no improvement in rice bran lecithin due to the retention
of degradation products. The proposed integrated
membrane process with nonporous (deoiling) and nanofiltration
(solvent recovery) membranes could be an attractive
preposition besides being an acetone free process.