Stability of Orange Oil-in-Water Emulsion Prepared by Multilayer Membranes

Abstract

Abstract

Due to the small molecular size of orange oil, primary orange oil–in-water emulsion can easilyundergo Ostwald ripening destabilization. To improve the stability of orange oil emulsion, multilayer emulsionwas prepared using Citrem as emulsifier and gelatin as coated biopolymer. Firstly, primary emulsioncontaining 20 wt% orange oil and 0.4 wt% Citrem was produced. Since Citrem was an anionic emulsifier,the primary emulsion had a negative charge of ~ -57mV. Then, the primary emulsion was suspended in0.5 wt% gelatin aqueous solution at pH 3 with the ratio of primary emulsion to gelatin aqueous solutionof 1:1. The gelatin that was positively charged at this pH condition coated around the primary emulsionand double layer emulsion (secondary emulsion) with a ζ-potential value of ~ +20 mV was Produced. Theparticle sizes of primary and secondary emulsions at various time intervals were detected using a laserdiffraction particle analyzer. The results showed that the average particle size (d3,2) of secondary emulsionon the first day was 1.5 (± 0.02) microns and that after storage at room temperature (~25 °C) for 14 dayswas 1.5 (± 0.02) microns, indicating good emulsion stability. The particle size of the primary emulsion (d3,2)increased from 1.3 (± 0.02) microns to 1.8 (± 0.02) micron, or increased by a factor of 1.4.

Keywords : Citrem; Emulsion; Gelatin; Multilayer emulsion; range oil; Ostwald ripening