Abstract

The aim of this study was to encapsulate orange peel oil (OPO) using microemulsion technique. Microemulsification of OPO with T60 and propanol was studied in 1:1, 1:2 and 2:1 surfactant:cosurfactant ratios. Dynamic light scattering results showed that the particle sizes of the OPO capsules in O/W microemulsions with 1% wt. oil were less than 20 nm. O/W microemulsion systems are good OPO vehicles and OPO release from these systems was more efficient than noncapsulated OPO. The protective effect of microemulsions on OPO was confirmed by exposing the pure and microemulsified essential oil to UV light. The effectiveness of microemulsions in encapsulating of OPO was verified by sensory assessment of beverages containing microemulsified OPO in comparison with ones containing free essential oil.

INTRODUCTION

Orange peel oil (OPO) is a popular flavoring agent in the food and pharmaceutical formulations due to its specific aroma and low cost but its application has been limited in different foods owing to its low aqueous solubility as well as stability during processing and storage which leads to changes in the sensory properties of the OPO and the products containing it (1). In order to increase the stability of products formulated with OPO and the possibility of OPO usage in aqueous formulations, encapsulation can be used as a method for entrapping the essential oil within a protective layer of coating materials. Microemulsions, potentially can be used for coating volatile compounds such as essential oils in order to increase their stability during storage or processing. Microemulsions are homogeneous, clear, and thermodynamically stable solutions, which consist of different ratios of oil, surfactant, cosurfactant and water (2). The transparency of the microemulsions is due to their droplet size (5 to 100 nm) which is smaller than the wavelength of the visible light (150 nm) (3). Surfactants play very important role in the formation of such syst ...