Membrane-based simultaneous degumming and deacidification of vegetable oils Abdellatif Hafidi a, * , Daniel Pioch b , Hamid Ajana a a Laboratoire Sciences des Aliments, Universite ´ Cadi Ayyad, Faculte ´ des Sciences Semlalia, BP 2390, Marrakech, Morocco b Physico-Chemistry of Processes and Bioenergy Laboratory, Agrifood Systems Programme CIRAD-AMIS, TA 40/16, 34398 Montpellier Cedex 5, France Received 20 January 2004; accepted 16 December 2004 Abstract An efficient membrane based process for simultaneous degumming and deacidification of vegetable oil was investigated. Appropriate crude oil conditioning allow the formation of submicronic aggregates, composed with soaps molecules resulting from the neutralisation of FFA and PL, which are retained when microfiltrating. Initial flux for the 0.8 Am membranes (~560 l/h m 2 ) was about twice that of the 0.5 Am and about 10 times that of 0.2 Am membrane. The filtered oils showed good quality in the case of 0.2 and 0.5 Am membranes, but the use of 0.8 Am membranes has allowed some soaps to pass through. Two types of crude oils behaviour were noticed. Oppositely to some oils for which just simple neutralisation led to a satisfactory elimination of the phospholipids, others were very tough to refine. The operating pression seems not to affect the efficiency of the separation, whereas the stability of the vesicle-like aggregates is found to be greatly affected by the increase of the temperature above 25 8C. Beside the quasi-elimination of FFA, PL and water, minerals and pigments contents were also greatly lowered. When using an NaOH 20%, the lovibond yellow score lowered from around 28 to 10 in the case of sunflower oils and from ~34 to 6–20 in the case of soya and rapeseed oils. The monoglycerides were almost undetectable after membrane processing whatever the type of the conditioning used. After processing, the diglycerides contents, which ranges in the tested crude oils between 0.8% and 1.0%, showed almost no changes for two oils, whereas noticeable increases were obtained for the other oils. Total phytosterols contents were systematically reduced. The reductions vary from 3% to 44% upon the case. Neutralisation with an NaOH 20% lead to higher sterol losses in comparison to NaOH 40%. All the sterol components contents were found to be reduced in almost similar proportions. D 2005 Elsevier Ltd. All rights reserved. Keywords: Vegetable oils; Degumming; Deacidification; Microfiltration; Minor components; Quality Industrial relevance: Conventional oil recovery and purification processes are continuousely sought to be replaced by gentler processing conditions. Membrane based oil refining operating at low temperatures and without the generation of waste water offer an interesting and promising approach towards bgreenerQ technologies. 1. Introduction Excepting extra virgin olive oils and some speciality oils, vegetable oils must undergo refining operations to remove undesirable components granting them thus satisfactory purity and stability characteristics (acidity, colour, oxidative, and sensory). Classical edible oil refining processes include degumming, neutralisation, bleaching, and deodorisation. These series of operations aim mainly to remove phospho- lipids (PL), free fatty acids (FFA), pigments, hydroper- oxides, and waxes. Such a processing can be operated according to two main schemes differing essentially in the manner the FFA are removed. In the so called chemical or alkali refining, they are turned to soaps by an alkali and, subsequently, removed from the neutral oil by centrifuga- tions and washing steps, whereas in physical refining they are distilled during the deodorisation operation. The two processes are reputed to be very energy-consuming. In addition, all the refining operations subject oils to high temperatures; consequently, quantitative and qualitative 1466-8564/$ - see front matter D 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.ifset.2004.12.001 * Corresponding author. Tel.: +212 44 43 46 49; fax: +212 44 43 74 12. E-mail address: a.Hafidi@ucam.ac.ma (A. Hafidi). Innovative Food Science and Emerging Technologies 6 (2005) 203– 212 www.elsevier.com/locate/ifset