Influence of droplet charge on the chemical stability of citral in oil-in-water emulsions.
The chemical stability of citral, a flavor component widely used in beverage, food, and fragrance products, in oil-in-water emulsions stabilized by surfactants with different charge characteristics was investigated. Emulsions were prepared using cationic (lauryl alginate, LAE), non-ionic (polyoxyethylene (23) lauryl ether, Brij 35), and anionic (sodium dodecyl sulfate, SDS) surfactants at pH 3.5. The citral concentration decreased over time in all the emulsions, but the rate of decrease depended on surfactant type. After 7 d storage, the citral concentrations remaining in the emulsions were around 60% for LAE- or Brij 35-stabilized emulsions and 10% for SDS-stabilized emulsions. An increase in the local proton (H(+)) concentration around negatively charged droplet surfaces may account for the more rapid citral degradation observed in SDS-stabilized emulsions. A strong metal ion chelator (EDTA), which has previously been shown to be effective at increasing the oxidative stability of labile components, had no effect on citral stability in LAE- or Brij 35-stabilized emulsions, but it slightly decreased the initial rate of citral degradation in SDS-stabilized emulsions. These results suggest the surfactant type used to prepare emulsions should be controlled to improve the chemical stability of citral in emulsion systems.
Choi
Seung Jun
SJ
Dept. of Food Science, Univ. of Massachusetts, Amherst, MA 01003, USA.
Decker
Eric Andrew
EA
Henson
Lulu
L
Popplewell
L Michael
LM
McClements
David Julian
DJ
D000080462:Acyclic Monoterpenes; D000464:Alginates / Q000737:chemistry; D055598:Chemical Phenomena; D004492:Edetic Acid / Q000737:chemistry; D045703:Emulsifying Agents / Q000737:chemistry*; D004655:Emulsions; D005421:Flavoring Agents / Q000032:analysis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007502:Iron Chelating Agents / Q000737:chemistry; D039821:Monoterpenes / Q000032:analysis / Q000737:chemistry*; D009821:Oils / Q000737:chemistry; D009994:Osmolar Concentration; D011092:Polyethylene Glycols / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000080462:Acyclic Monoterpenes; D000464:Alginates; D045703:Emulsifying Agents; D004655:Emulsions; D005421:Flavoring Agents; D007502:Iron Chelating Agents; D039821:Monoterpenes; D009821:Oils; C555020:lauryl alginate; D014867:Water; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols; D004492:Edetic Acid; C515901:Brij 35; C007076:citral