Degumming and production of soy lecithin, and the cleaning of a ceramic membrane used in the ultrafiltration and diafiltration of crude soybean oil

The optimization of the cleaning process, aiming to recover the permeate flux, and diafiltration as a means to obtain and purify soybean lecithin, were analyzed in this study as a means of delaying the decrease in permeate flux during the ultrafiltration (UF) of vegetable oils and their derivatives. It also aimed to maximize the exploration of the use of this type of technology during the processing steps. Thus the influence of the transmembrane pressure, cross flow velocity, and the opening of the permeate valve during the cleaning process (hexane circulation) of a ceramic membrane with a permeation area of 0.2 m² and a pore diameter of 0.01 mm in a pilot unit with a processing capacity of 40 L, was studied. Four different operational cleaning conditions, associating combinations of pressure (0.5–2.0 bar) and velocity (1.0–5.0 m s⁻¹), as well as the influence of opening the permeate valve, were studied. Also the production and purification of soybean lecithin was carried out by diafiltration of the retentates derived from the UF of the miscella, resulting in a product with about 90% of acetone insoluble matter. The most favorable cleaning condition was associated with a low pressure (0.5 bar) and elevated velocity (5.0 m s⁻¹), with which it was possible to recover the permeate flux in about 85 min.