August 4/Amherst, Mass./Chemical & Chemistry -- According to recent research from the U.S., "The oxidative stability and lipid digestibility of fish oil-in-water emulsions (d(43); 5.26-5.71 mu m) laminated by primary, secondary, and/or tertiary layers of interfacial membranes have been investigated. The primary emulsion (5 and 0.5% wt % of fish oil and Citrem in acetate buffer) was produced through a membrane homogenizer."

"The second and tertiary emulsions were prepared by electrostatic deposition of chitosan and sodium alginate on the surfaces of the oil droplets, respectively. The lamination of biopolymers was measured by zeta potential. The lipid oxidative stability was assessed with peroxide value, thiobabituric acid reactive substances, and headspace aldehydes of the emulsions stored at 20 degrees C for 40 days. The positively charged secondary emulsions (+56.27 +/- 2.5 mV) were more stable to lipid oxidation compared to negatively charged primary (-45.13 +/- 1.7 mV) and tertiary emulsions (-24.8 +/- 1.2 mV). An in vitro digestion model was used to study the impact of different layers on the digestibility of oil droplets. Lipid digestion was decreased with multilayer Coating, and chitosan coating further reduced the digestion," wrote V. Gudipati and colleagues, University of Massachusetts.

The researchers concluded, "These findings have implications for the design of structured emulsions to achieve better oxidative stability with more controlled digestibility of lipids."

Gudipati and colleagues published their study in the Journal of Agricultural and Food Chemistry ("Oxidative Stability and in Vitro Digestibility of Fish Oil-in-Water Emulsions Containing Multilayered Membranes." Journal of Agricultural and Food Chemistry, 2010;58(13):8093-8099).

For additional information, contact E.A. Decker, University of Massachusetts, Dept. of Food Science, Amherst, MA 01003.

From the August 16, 2010, Prepared Foods E-dition