Laboratory Studies on Membrane Deoiling of Lecithin

Abstract

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.

Preparation of Deoiled Soy Lecithin by Ultrafiltration

“…An ultrafiltrationbased process was developed in 1998 by Archer Daniels Midland Company (ADM, USA) using polyvinylidene fluoride membrane with a molecular weight cut-off (MWCO) of 10-50 kDa, which produced deoiled lecithin with a 90% AI content [10], a relatively high purity, although not reaching the deoiled lecithin standard set by the Central Soya Company [11]. A nonporous membrane based on the diafiltration process has also been used in deoiling lecithin [12], resulting in an increase in the AI content of soy lecithin from 63.2 to 81.0% in a single-step batch operation. Nonporous membranes were able to reject PL reverse micelles as well as their monomers.…”

Soybean-based Surfactants and Their Applications

“…However, cost is a major concern as the processes are usually performed under high pressures and high temperatures. Manjula & Subramanian [2008] investigated the de-oiling of lecithin using a nonporous polymeric membrane and hexane as the solvent. Their results demonstrated that the membrane is a promising alternative for the de-oiling of lecithin, especially in terms of cost effectiveness.…”