Author(s): Candéa, Tatiana Vidal
Date: 2013
Persistent ID: http://hdl.handle.net/10362/10412
Origin: Repositório Institucional da UNL
Subject(s): Linseed oil; Premix membrane emulsification; Direct membrane emulsification; Food emulsions; Bioactive lipids
Dissertation presented to Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa for obtaining the master degree in Membrane Engineering
Food emulsions play an important role in product development and formulation, as well as to encapsulation of food additives. Conventional methods for emulsion production may present some drawbacks, such as the use of high shear stress, high energy demanding and polydisperse droplet size distribution. In this sense, membrane emulsification emerges as an alternative method to overcome all this issues and to produce fine and stable emulsions. Linseed oil has been widely studied in the last years, due to its nutritional composition, being the richest ω-3 vegetable source and for that reason it was used as the raw material for emulsion production. Premix and direct (cross flow) membrane emulsification were carried out using three different membrane materials: polissulphone, cellulose ester and α-alumina membrane. For premix membrane emulsification (PME) the variables transmembrane pressure, membrane material, surfactant type and membrane mean pore size were evaluated. The membrane mean pore size was the crucial factor to achieve emulsions by PME, once it was not possible to achieve stable emulsion with mean pore sizes lower than 0.8 μm. For direct membrane emulsification, transmembrane pressure, surfactant concentration and cross flow velocity were evaluated by means of a experimental design. The evaluated responses were stability, droplet size and distribution and dispersed phase flux. For all the variables studied, only dispersed phase flux showed to have significant influence of pressure. Comparing both methods of membrane emulsification, premix showed to be more suitable in terms of emulsion production throughput and droplet size correlation with membrane pore size, however, in terms of stability, direct membrane emulsification showed much better results. Encapsulation of linseed oil by spray drying was promoted using the optimum point of the performed experimental design and the droplets size distribution has considerably changed with the addition of the wall material to the emulsion.
The EM3E Master is an Education Programme supported by the European Commission, the European Membrane Society (EMS), the European Membrane House (EMH), and a large international network of industrial companies, research centres and universities
