Oil-in-water (O/W) nanoemulsion loaded with biotransformation product containing limonene and α-terpineol stabilized with Tween®20: Formation and physicochemical stability along with time

Abstract

Aroma chemicals are essential in the food industry as they are added to numerous food products to enhance sensory experience. However, preserving the shelf-life and maintaining the physicochemical stability of these additives is a challenging task for food processors. Encapsulation techniques can help overcome these challenges by facilitating incorporation, increasing loading capacity and enabling controlled release of flavor oils. This study specifically focused on encapsulating a biotransformation product comprising a blend of alpha-terpineol (α-TOH), limonene (LIM), and soybean oil, obtained through bioconversion of limonene in a submerged liquid fermentation media using Sphingobium sp. as a biocatalyst. By using Tween®20 as a surfactant, an oil-in-water nanoemulsion system was used as encapsulation strategy to extend the shelf life of these sensitive flavor oils. Subsequently, the nanoemulsified samples were subjected to varying temperatures (5 °C, 25 °C, and 50 °C) for up to 600 days. The physical stability of the samples we assessed by measuring mean droplet diameter and turbidity, while chemical stability was analyzed using gas chromatography (GC). Findings revealed that physical stability was maintained for up to 600 days at 5 °C and 25 °C. Conversely, the nanoemulsion broke down on the 120th day when exposed to 50 °C. Furthermore, it was found that the chemical stability was temperature-dependent, with losses of LIM and α-TOH increasing as the storage temperature rose. In conclusion, this study emphasizes the critical role of encapsulation techniques in prolonging the shelf life of sensitive compounds such as aroma chemicals.