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Physicochemical properties and microencapsulation process development for fish oil using supercritical carbon dioxide Open Access


Other title
gum arabic
quartz crystal microbalance
fish oil
supercritical carbon dioxide
beta glucan
interfacial tension
particle formation
gas expanded ethanol
Type of item
Degree grantor
University of Alberta
Author or creator
Seifried, Bernhard
Supervisor and department
Temelli, Feral (Agricultural, Food and Nutritional Science)
Examining committee member and department
Jessop, Philip G. (Chemistry, Queen's University)
Bressler, David (Agricultural, Food and Nutritional Science)
Vasanthan, Thava (Agricultural, Food and Nutritional Science)
Yeung, Anthony (Chemical and Materials Engineering)
Department of Agricultural, Food and Nutritional Science

Date accepted
Graduation date
Doctor of Philosophy
Degree level
Fish oil is an excellent source of long chain polyunsaturated fatty acids (LC-PUFA), which can reduce the risk of cardiovascular disease in addition to other health benefits. However, the average intake of LC-PUFA in the Western diet is much lower than the recommended levels. Fish oil is prone to oxidative deterioration when exposed to oxygen and thus must be protected in order to be used in food products. Microencapsulation is one possibility that is already applied by the industry to protect fish oil. However, most of the conventional microencapsulation techniques suffer from shortcomings such as harsh processing conditions or the use of numerous chemicals. The main objective of this thesis was to develop a novel spray process to microencapsulate fish oil based on supercritical fluid (SCF) technology using supercritical carbon dioxide (SC-CO2) and CO2-expanded ethanol (CX EtOH). Fundamental physicochemical properties essential for optimal process design were lacking in the literature; therefore, density, interfacial tension (IFT) and viscosity of fish oil in the form of triglycerides and fatty acid ethyl esters were determined at different temperatures and pressures. Fish oil when equilibrated with SC-CO2 at elevated pressure expanded by up to about 40% in volume and increased in density by up to about 5%. Furthermore, IFT of fish oil in contact with SC-CO2 decreased substantially by an order of magnitude with an increase in CO2 pressure. When fish oil was in contact with CX EtOH, IFT decreased to ultra low levels at pressures of less than 10 MPa. Viscosity of fish oil equilibrated with SC-CO2 decreased substantially with pressure but increased with shear rate. Based on the physicochemical properties determined in this research, a novel process to produce micro- and nano-sized particles containing fish oil was developed based on a SCF spray-drying method. Key processing parameters have been evaluated and can be further optimized to improve encapsulation efficiency. Determination of physicochemical properties contributed to the fundamental understanding of the behavior of the fish oil+CO2 system with and without ethanol under high pressure conditions. The new microencapsulation process shows great potential for the delivery of bioactives in various product applications.
License granted by Bernhard Seifried ( on 2010-04-15T18:16:23Z (GMT): Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of the above terms. The author reserves all other publication and other rights in association with the copyright in the thesis, and except as herein provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
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