Food & Nutrition

Arab Journal of Food & Nutrition
107. Nanoencapsulation of Omega-3 Fatty Acid and Modeling its Thermal
Stability (2010)
Salam M. Habib\ University of Jordan
Supervisor: Dr. Ayed S. Amr, Prof.
Co-Supervisor: Dr. Imad M. Hamadneh
Α-linolenic acid (α-LA), an omega-3 fatty acid, was nanoencapsulated by a
modified emulsion diffusion technique using polylactic acid (PLA) as the
encapsulating polymer. Combinations of acetone and ethyl acetate as organic solvents,
Tween 20, Pluronic–F68 and gelatin as stabilizers were used in the preparation with
varying organic to aqueous phase ratios. Organic phase that contains α-LA and PLA in
organic solvent was added drop wise to the aqueous phase that contains 1% stabilizer
in water. High shear mixing for five minutes at 10,000 rpm/min was applied to the
mixture. Water as dilution phase was added to allow for organic solvent diffusion and
nanocapsule formation by the precipitation and aggregation of polymer on the surface
of the hydrophobic α-LA core.
The nanocapsule dispersions obtained had a diameter of less than 100 nm as
verified by the scanning electron microscopy images. Particle size and Zeta potential
as measured by the dynamic light scattering technique using a particle size analyzer
were influenced by different preparation conditions such as the type of solvent,
stabilizer and the ratios of organic to aqueous phases used. Acetone as a solvent,
Tween 20 as a stabilizer and an organic to aqueous phase ratio of 1:5 were the best
conditions among those which were tried to produce smaller nanocapsules.
Accelerated storage studies showed a superior thermal stability exhibited by the
nanoencapsulated α-LA compared to the non-encapsulated α-LA, where the percent
retention of α-LA was about five to six times higher in the nano- over the nonencapsulated
α-LA after ten hours of storage at 40 and 80ºC. Moreover,
nanoencapsulated α-LA showed a significant superior storage stability compared to the
non-encapsulated fatty acid when used as an ingredient of infant formula. The
developed mathematical model of the behavior of nanoencapsulated α-LA showed a
more pronounced effect of time of storage as compared to the temperature in the
stability of the acid. The noted high stability of nanoencapsulated α-LA makes it
possible to present it as a novel enrichment technique for food.
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Volume 11, No. 25, 2011
135