title: Influence of droplet size on the antioxidant activity of rosemary extract loaded oil-in-water emulsions in mixed systems.
abstract: The influence of droplet size on the antioxidant activity of oil-in-water emulsions loaded with rosemary extract in mixed emulsion systems was investigated. Firstly, differently sized hexadecane-in-water model emulsions (10% (w/w) hexadecane, 2% (w/w) Tween 80, pH 5 or 7) containing 4000 ppm rosemary extract in the oil phase or without added antioxidant were prepared using a high shear blender and/or high-pressure homogenizer. Secondly, emulsions were mixed with fish oil-in-water emulsions (10% (w/w) fish oil, 2% (w/w) Tween 80, pH 5 or 7) at a mixing ratio of 1 : 1. Optical microscopy and static light scattering measurements indicated that emulsions were physically stable for 21 days, except for the slight aggregation of emulsions with a mean droplet size d₄₃ of 4500 nm. The droplet size of hexadecane-in-water emulsions containing rosemary extract had no influence on the formation of lipid hydroperoxides at pH 5 and 7. Significantly lower concentrations of propanal were observed for the emulsions loaded with rosemary extract with a mean droplet size d₄₃ of 4500 nm from day 12 to 16 at pH 7. Finally, hexadecane-in-water emulsions containing rosemary extract significantly retarded lipid oxidation of fish oil-in-water emulsions in mixed systems, but no differences in antioxidant efficacy between the differently sized emulsions were observed at pH 5.
authors.affiliation: Department of Food Physics and Meat Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 21/25, 70599 Stuttgart, Germany. j.weiss@uni-hohenheim.de.
authors.forename: Martin E
authors.initials: ME
authors.lastname: Erdmann
authors.forename: Benjamin
authors.initials: B
authors.lastname: Zeeb
authors.forename: Hanna
authors.initials: H
authors.lastname: Salminen
authors.forename: Monika
authors.initials: M
authors.lastname: Gibis
authors.forename: Ralf
authors.initials: R
authors.lastname: Lautenschlaeger
authors.forename: Jochen
authors.initials: J
authors.lastname: Weiss
mesh_terms: D000447:Aldehydes / Q000032:analysis / Q000037:antagonists & inhibitors / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry; D000818:Animals; D000975:Antioxidants / Q000032:analysis / Q000737:chemistry*; D004041:Dietary Fats / Q000032:analysis; D019587:Dietary Supplements / Q000032:analysis*; D004224:Diterpenes / Q000032:analysis / Q000737:chemistry; D004655:Emulsions; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D005395:Fish Oils / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008054:Lipid Peroxides / Q000032:analysis / Q000037:antagonists & inhibitors / Q000737:chemistry; D008823:Micelles; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D027542:Rosmarinus / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D000473:Alkanes; D000975:Antioxidants; D004041:Dietary Fats; D004224:Diterpenes; D004655:Emulsions; D005227:Fatty Acids; D005395:Fish Oils; D008054:Lipid Peroxides; D008823:Micelles; D010936:Plant Extracts; C005556:propionaldehyde; C007932:n-hexadecane