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.
- multilayered emulsion,
- electrostatic deposition,
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