References 1 Kober, P.A. (1917) ‘Pervaporation, Perstillation and Percrystallization’ in 1. Am. Chem. Sot. 39,944-948 2 Maeda, Y. and Kai, M. (1991) ‘Recent Progress in Pervaporation for Water/Ethanol Separation’ in Pervaporation Membrane Separation Processes (Huang, R.Y.M., ed.), pp. 391-435, Elsevier 3 Mulder, M. (1992) Basic Prmciples ofMembrane Technology, Kluwer Academic Press 4 Karlsson, H.O.E. and Tr&@dh, C. (1993) ‘Aroma Compound Recovery with Pervaporation - Feed Flow Effects’ in 1. Membr. Sci. 81, 163-171 5 Hiimpler, C. and Bode, E. (1995) ‘Single Permeant Pervaporation Through Surface Modified and Multiple Layers Membranes’ in Proceedings of the Seventh International Conference on Pervaporation Processes in the Chemical Industry (Bakish, R., ed.), pp. 182-l 92, Bakish Materials Corporation, Englewood, NJ, USA 6 Koops, C.H. and Smolders, C.A. (1991) ‘Estimation and Evaluation of Polymeric Materials for Pervaporation Membranes’ in Pervaporation Membrane Separation Processes (Huang, R.Y.M., ed.), pp. 253-278, Elsevier 7 Karlsson, H.O.E. and Tr;igdrdh, G. (19931 ‘Pervaporation of Dilute Organic-Water Mixtures. A Literature Review on Modelling Studies and Applications to Aroma Compound Recovery’ in 1. Membr. Sci. 76, 121-l 46 8 Sulc, D. (1984) ‘Fruchtsaftkonzentrierung und Fruchtaromaseparierung’ in Confructa Studien 28, 258-318 9 Mannheim, C.H. and Passy, N. (1975) ‘Aroma Recovery and Retention in Fruit Juices’ in fnt. F/avows Food Addit. 6, 323-328 10 Karlsson, H.O.E. and Tr;igdrdh, G. (1994) ‘Aroma Compound Recovery with Pervaporation - The Effect of High Ethanol Concentrations’ in 1. Membr. Sci. 91, 189-198 11 Bomben, J.L., Kitson, J.A. and Morgan, A.I. (1966) ‘Vacuum Stripping of Aromas’ in Food Jechnol. 20, 125-l 28 12 Escoudier, J.L., Le Bouar, M., Moutounet, M., Jouret, C. and Barillere, J.M. (1988) ‘Application and Evaluation of Pervaporation for the Production of Low Alcohol Wines’ in Proceedings of the Third Jnternational Conference on Pervaporation Processes in the Chemical Industry (Bakish, R., ed.), pp. 387-397, Bakish Materials Corporation, Englewood, NJ, USA 13 Hickey, P.J. and Cooding, C.H. (1994) ‘The Economic Optimization of Spiral Wound Membrane Modules for the Pervaporative Removal of VOCs from Water’ in /. Membr. Sci. 97, 53-70 14 BrOschke, H.E.A. (1990) ‘Removal of Ethanol from Aqueous Streams by Pervaporation’ in Desalination 77, 323-329 15 Kimmerle, K. and Gudernatsch, W. (1991) ‘Pilot Dealcoholization of Beer by Pervaporation’ in Proceedings of the Fifth International Conference on Pervaporation Processes in the Chemical /ndustry (Bakish, R., ed.), pp. 291-307, Bakish Materials Corporation, Englewood, NJ, USA 16 Lee, E.K. (1993) in Science for the Food /ndustry of the Zlst Century, Biotechnology, Supercritical Fluids, Membranes and Other Advanced Technologies for low Calorie, Healthy Food Alternatives (Yalpani, M., ed.), pp. 195-212, ATL Press 17 Lee, E.K., Kalyani, V.J. and Matson, S.L. (1991) ‘Process for Treating Alcoholic Beverages by Vapor-arbitrated Pervaporation’, US Patent 5 013 447 18 Koseoglu, S.S., Hernandez, E., Shah, V. and Tuohey, D. (1995) ‘Opportunities for Pervaporation: Processing Edible Oils and Fats’ in Proceedings ofthe Seventh International Conference on Pervaporation Processes in the Chemical Industry (Baklsh, R., ed.), pp. 263-270, Bakish Materials Corporation, Englewood, NJ, USA 19 Rautenbach, R., Klatt, S. and Vier, I. (1992) ‘State of the Art of Pervaporation - 10 Years of Industrial PV’ in Proceedings oithe Sixth International Conference on Pervaporation Processes in the Chemical Industry (Bakish, R., ed.), pp. 2-l 5, Bakish Materials Corporation, Englewood, NJ, USA 20 van Gemert, R.W. and Cuperus, F.P. (1995) ‘Newly Developed Ceramic Membranes for Dehydration and Separation oi Organic Mixtures by Pervaporation’ in 1. Membr. Sci. 105,287-291 21 Sano, T., Hasegawa, M., Kawakami, Y. and Yanagishita, H. (1995) ‘Separation of Methanol/Methyl-terf-butyl Ether Mixture by Pervaporation Usmg Zeolite Membrane’ in 1. Membr. Sci. 107, 193-l 96 Review Lipid oxidation is a major cause of quality deterioration in food emulsions. The design of foods with improved quality depends on a better understanding of the physicochemical mechanisms of lipid oxidation in these systems. The oxidation of emulsified lipids differs from that of bulk lipids, because of the presence of the droplet membrane, the interactions between the ingredients, and the partitioning of ingredients between the oil, aqueous and interfacial regions. Lipid oxidation in food emulsions John N. Coupland and D. Julian McClements Lipid oxidation is of great concern to the food industry because it leads to the development of undesirable ‘off- flavors’ (rancidity) and potentially toxic reaction prod- ucts’. Food manufacturers must therefore develop meth- ods of preventing, or at least retarding, lipid oxidation in foods. To do this effectively, it is necessary to have a John N. Coupland and D. Julian McClements (corresponding author) are at the Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA (fax: +l-413-545-1262; e-mail: mcclements@foodsci.umass.edu). Trends in Food Science & Technology March 1996 [Vol. 71 thorough understanding of the mechanisms of lipid oxi- dation, and how these are affected by the physicochemical environment of the lipids. Lipid oxidation has been extensively studied in bulk fats and oils, and there is now a fairly good understand- ing of the factors that affect oxidation in such systems’. Research in this area has attempted to elucidate the mechanisms by which lipid oxidation proceeds under various conditions, and the resultant reaction products. Understanding of the factors that affect lipid oxidation in systems in which the fat is dispersed as emulsion 01996, Elsewer Scmce Ltd 83