Enhancement of the Stability of W/O/W Double Emulsion by Chitosan Modified Rice Husk Silica

Abstract

The awareness of the need for healthy food continues to increase, hence, the demand for healthy food is also increasing. Water-in-oil-in-water (W/O/W) double emulsion can provide lowfat emulsion-based products due to a lower fraction of oil compared to the corresponding O/W emulsion. However, the stability of double emulsion has been quite tricky to be established due to the presence of two interfacial layers between oil and water. This research aims to study the use of biosilica in the form of rice husk ash (RHA) combined with both chitosan particles and chitosan solution to stabilize the interfacial layer between oil droplets and the outer aqueous phase. The concentrations of chitosan and biosilica, as well as pH of the outer aqueous phase in the acidic ranges, were varied to obtain W/O/W emulsion with higher stability. The primary emulsion was prepared by using the emulsifier mixtures of Tween 20 and Span 80. The resulting primary emulsion was subsequently dispersed into the outer aqueous phase, loaded with the combination of biosilica and chitosan particles/ solution. Emulsification processes were conducted using a rotorstator homogenizer. The resulting W/O/W emulsions with high stability of ~80-100% were obtained by using the combination of 0.5% biosilica and 1.25% chitosan particles/ 5.25% chitosan solution at the pH of 4. The use of biosilica and chitosan seemed promising to be applied in the manufacturing of healthier food emulsion-based products.