Factors Affecting Foamed Emulsions Prepared with an Extract from Quillaja saponaria Molina: Oil Droplet Size, pH and Presence of Beta-Lactoglobulin

Oil is well-known to act as antifoam and to destabilize foam lamellae by bridging between two adjacent foam bubbles. It was hypothesized that an optimal oil droplet size exists with respect to the stability of a foamed emulsions, where the oil droplets are sufficiently small to postpone bridging and...

Full description

Saved in:
Bibliographic Details
Published in:Food biophysics 2017-06, Vol.12 (2), p.250-260
Main Authors: Böttcher, Sandra, Eichhorn, Marina, Drusch, Stephan
Format: Article
Language:English
Subjects:
Analytical Chemistry
Biological and Medical Physics
Biophysics
Capillary pressure
Chemistry
Chemistry and Materials Science
Droplets
Edible oils
Emulsification
Emulsifiers
Emulsion polymerization
Emulsions
Fluids
Food
Food Science
Lactoglobulin
Lamellae
Molecular interactions
Mud-water interfaces
Oils & fats
Original Article
pH effects
Pressure
Proteins
Saponins
Stability
β-Lactoglobulin
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Oil is well-known to act as antifoam and to destabilize foam lamellae by bridging between two adjacent foam bubbles. It was hypothesized that an optimal oil droplet size exists with respect to the stability of a foamed emulsions, where the oil droplets are sufficiently small to postpone bridging and the amount of free surfactant is sufficient to stabilize the oil/water-interface and the air/water-interface. Emulsions with 0.3% Quillaja saponin and a median oil drop-let size between 0.2 and 2.0 μm were prepared under varying homogenization conditions and characterized in a dynamic foam analyzer. Results confirmed the above mentioned hypothesis. Stability of the foamed emulsions considerably increased with increasing pH, which was attributed to electrostatic repulsion between oil droplets and the effect on the balance between disjoining pressure and capillary pressure. In a binary system containing proteins and saponins, stability of foamed emulsions can be further increased when emulsifiers are added sequentially. When the emulsion is stabilized by β-LG and QS is added after emulsification stability of the foamed emulsion is distinctly higher compared to systems, where QS and β-LG are added prior to emulsification. Future studies should deepen our understanding of these complex dispersed systems by investigating the molecular interactions including other proteins and additional food constituents.
ISSN:1557-1858
1557-1866
DOI:10.1007/s11483-017-9481-8