Formulation and physicochemical stability of oil-in-water nanoemulsion loaded with α-terpineol as flavor oil using Quillaja saponins as natural emulsifier

Abstract

Alpha-terpineol (α-TOH) is a promising monoterpenoid detaining several biological activities. However, as a volatile molecule, the incorporation of α-TOH within formulated products poses several challenges related to its stability. In this sense, nanoencapsulation works as a key technology to protect the bioactivity of low molecular weight oils, like α-TOH, against environmental stresses (heat, light, and moisture), mitigating their susceptibility to degradation (oxidation and volatilization). Physical properties of encapsulated flavor/essential oil have been extensively reported, whereas there is a lack in the literature regarding their chemical stability, which is usually the main purpose of encapsulation. Thus, in this study, the physicochemical stability of the formulated oil-in-water nanoemulsion loaded with α-TOH stabilized with Quillaja saponins (QSs) as a natural emulsifier (α-TOH-QSs-NE) were tracked in a long-term (up to 280th day). Along with time, mean droplet diameter (MDD) and turbidity were used as a reference for physical parameters; while the chemical stability was monitored using gas chromatography analysis to quantify the mark content of α-TOH into the NE. Results indicated that α-TOH-QSs-NE was successfully formulated with a high-load amount of α-TOH (90 mg mL−1). α-TOH-QSs-NE showed great physicochemical stability regardless the storage-temperature (5 °C or 25 °C) up to 280th day, with no significant alterations in the MDD or turbidity, where c.a. 79% of the initial amount of the nanoemulsified α-TOH remained detectable in α-TOH-QSs-NEs, with no finding of degradation products. Thus, the data here disclosure may be useful for innovative application of α-TOH in foodstuffs.