Influence of sucrose on droplet flocculation in hexadecane oil-in-water emulsions stabilized by beta-lactoglobulin.
The influence of sucrose on the flocculation stability of hydrocarbon oil-in-water emulsions stabilized by a globular protein was examined using laser diffraction. Salt (150 mM NaCl) and sucrose (0-40 wt %) were added to n-hexadecane oil-in-water emulsions stabilized by beta-lactoglobulin (beta-Lg, pH 7.0) either before or after isothermal heat treatment (30-95 degrees C for 20 min). When salt was added to emulsions before heat treatment, appreciable droplet flocculation was observed below the thermal denaturation temperature of the adsorbed beta-Lg (T(m) approximately 70 degrees C), and more extensive flocculation was observed above T(m). On the other hand, when salt was added to emulsions after heat treatment, appreciable droplet flocculation still occurred below T(m), but little flocculation was observed above T(m). Addition of sucrose to the emulsions increased T(m) and either promoted or suppressed droplet flocculation depending on whether it was added before or after heat treatment. These results are interpreted in terms of the influence of sucrose on protein conformational stability, protein-protein interactions, and the physiochemical properties of aqueous solutions. This study has important implications for the formulation and production of protein stabilized oil-in-water emulsions.
Kim
Hyun-Jung
HJ
Biopolymers and Colloids Research Laboratory, Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Decker
Eric A
EA
McClements
David J
DJ
D000327:Adsorption; D000473:Alkanes / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004355:Drug Stability; D004655:Emulsions / Q000737:chemistry*; D005427:Flocculation; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007782:Lactoglobulins / Q000737:chemistry*; D010316:Particle Size; D011487:Protein Conformation / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology; D012996:Solutions; D013395:Sucrose / Q000494:pharmacology*; D014867:Water
D000473:Alkanes; D004655:Emulsions; D007782:Lactoglobulins; D012996:Solutions; D014867:Water; D012965:Sodium Chloride; D013395:Sucrose; C007932:n-hexadecane