title: Chemical and physical stability of citral and limonene in sodium dodecyl sulfate-chitosan and gum arabic-stabilized oil-in-water emulsions.
abstract: Citral and limonene are the major flavor components of citrus oils. Both of these compounds can undergo chemical degradation leading to loss of flavor and the formation of undesirable off-flavors. Engineering the interface of emulsion droplets with emulsifiers that inhibit chemical reactions could provide a novel technique to stabilize citral and limonene. At present, emulsified flavor oils are usually stabilized by gum arabic (GA), which is a naturally occurring polysaccharide-protein complex. The objective of this study was to examine if citral and limonene were more stable in emulsions stabilized with a sodium dodecyl sulfate (SDS)-chitosan complex than GA. Citral degraded less in GA-stabilized than in SDS-chitosan-stabilized emulsions at pH 3.0. However, SDS-chitosan-stabilized emulsions were more effective at retarding the formation of the citral oxidation product, p-cymene, than GA-stabilized emulsions. Limonene degradation and the formation of limonene oxidation products, limonene oxide and carvone, were lower in the SDS-chitosan- than GA-stabilized emulsions at pH 3.0. The ability of an SDS-chitosan multilayer emulsifier system to inhibit the oxidative deterioration of citral and limonene could be due to the formation of a cationic and thick emulsion droplet interface that could repel prooxidative metals, thus decreasing prooxidant-lipid interactions.
authors.affiliation: Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors.forename: Darinka
authors.initials: D
authors.lastname: Djordjevic
authors.forename: Luisito
authors.initials: L
authors.lastname: Cercaci
authors.forename: Jean
authors.initials: J
authors.lastname: Alamed
authors.forename: D Julian
authors.initials: DJ
authors.lastname: McClements
authors.forename: Eric A
authors.initials: EA
authors.lastname: Decker
mesh_terms: D000080462:Acyclic Monoterpenes; D048271:Chitosan / Q000737:chemistry*; D053138:Cyclohexenes / Q000737:chemistry*; D004355:Drug Stability; D004655:Emulsions / Q000737:chemistry; D006170:Gum Arabic / Q000737:chemistry*; D000077222:Limonene; D039821:Monoterpenes / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013649:Taste; D013729:Terpenes / Q000737:chemistry*
chemical_list: D000080462:Acyclic Monoterpenes; D053138:Cyclohexenes; D004655:Emulsions; D039821:Monoterpenes; D013729:Terpenes; D012967:Sodium Dodecyl Sulfate; D006170:Gum Arabic; D048271:Chitosan; D000077222:Limonene; C007076:citral