title: Cross-linking oppositely charged oil-in-water emulsions to enhance heteroaggregate stability.
abstract: The formation and subsequent enzymatic and chemical cross-linking of heteroaggregates from oppositely charged oil-in-water (O/W) emulsions was investigated. For this purpose, 10% (w/w) oil-in-water emulsions (d43<1 μm) were prepared at pH 4 using a positively charged emulsifier (Nα-lauroyl-L-arginine ethyl ester (LAE), cold water fish gelatin, or whey protein isolate) or a negatively charged one (sugar beet pectin or Quillaja saponins). The oppositely charged emulsions were then combined at a volume ratio of 1:1 and treated with laccase or glutaraldehyde in order to further stabilize the electrostatically attached aggregates by covalently cross-linking the oppositely charged membranes. Emulsions and heteroaggregates were characterized by their rheological properties, their surface charge, particle size distribution, and microstructure using dynamic and static light scattering as well as confocal laser scanning microscopy. Prior to cross-linking, the emulsifiers' stabilization mechanism were found to greatly influence the formation of heteroaggregates. Laccase treatment (1.34 mU/mL) increased aggregate expansion by ca. 30% for the combined emulsions stabilized by Quillaja saponins/whey protein isolate, while combined Quillaja saponins/fish gelatin stabilized emulsions remained unaffected. When combined emulsions were treated with 50mM glutaraldehyde, aggregate size significantly increased 2- and 3-fold, respectively. Thus, our study provides novel insights into the enzymatic and chemical cross-linking of heteroaggregates composed of oppositely charged O/W emulsions.
authors: Department of Food Physics and Meat Science, University of Hohenheim, Garbenstrasse 21/25, 70599 Stuttgart, Germany.
authors: Christiane
authors: C
authors: Maier
authors: Department of Food Physics and Meat Science, University of Hohenheim, Garbenstrasse 21/25, 70599 Stuttgart, Germany.
authors: Anja M
authors: AM
authors: Oechsle
authors: Department of Food Physics and Meat Science, University of Hohenheim, Garbenstrasse 21/25, 70599 Stuttgart, Germany. Electronic address: j.weiss@uni-hohenheim.de.
authors: Jochen
authors: J
authors: Weiss
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004355:Drug Stability; D045703:Emulsifying Agents / Q000737:chemistry; D004655:Emulsions; D005780:Gelatin / Q000737:chemistry; D005976:Glutaral / Q000737:chemistry; D042845:Laccase / Q000737:chemistry; D009821:Oils / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D000067816:Whey Proteins / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D045703:Emulsifying Agents; D004655:Emulsions; D009821:Oils; D012503:Saponins; D000067816:Whey Proteins; D014867:Water; D005780:Gelatin; D001120:Arginine; C489258:arginine ethyl ester; D042845:Laccase; D005976:Glutaral
keywords: Aggregation; Emulsifier; Glutaraldehyde; Laccase; Oil-in-water emulsion; Stability