Microencapsulation by Complex Coacervation of Lavender Oil Obtained by Steam Distillation at Semi-Industrial Scale

Abstract

Lavender oil (LEO) is one of the most well-known essential oils worldwide which, besides its extensive application in aromatherapy, serves as raw material for various fields, including the food, cosmetic, and pharmaceutical industries. Accordingly, several global requirements were established to warrant its quality. Microencapsulation represents an emerging technology widely applied for the preservation of essential oils, simultaneously providing new ways of application. In the current study, lavender oil was obtained from the flowering tops of Lavandula angustifolia Mill. on a semi-industrial-scale steam distillation system. According to the GC-MS investigation, lavender oil obtained in the third year of cultivation met the European Pharmacopoeia standards for linalyl acetate and linalool contents ≈38% and ≈26%, respectively. Microcapsules (MCs) containing the so-obtained essential oil were successfully produced by complex coacervation technology between gum arabic (GA) and three different grades of type-A gelatin (GE). Optical microscopic investigations revealed a significant difference in particle size depending on the gelatin grade used. The variation observed for coacervates was well reflected on the scanning electron micrographs of the freeze-dried form. The highest encapsulation efficiency values were obtained by UV-VIS spectrophotometry for microcapsules produced using gelatin with the medium gel strength. FT-IR spectra confirmed the structural modifications attributed to microencapsulation. According to the GC-MS analysis of the freeze-dried form, the characteristic components of lavender oil were present in the composition of the encapsulated essential oil.

Keywords: Lavandula angustifolia Mill.; complex coacervation; microencapsulation.

Figure 1

Requirements for the quantitative composition of LEO according to the European Pharmacopoeia 11th Edition and ISO 3515:2002 standard (“other origins” category).

Figure 2

Different development stages of lavender plantation (Lavandula angustifolia Mill.).

Figure 3

Parts of the semi-industrial-scale steam distillation system: perforated basket for biomaterial (a), bioreservoir with steam inlet ring (b), heat exchanger (c), and separation vessel (d).

Figure 4

Process steps of LEO microcapsule formation.

Figure 5

Optical microscopic images of experiments (LA011, LA010, and LA013) at different magnifications: (a) 40×, (b) 100×, and (c) 400×.

Figure 6

Macroscopic aspect of the lyophilized samples obtained with different gelatin grades (exp. no. LA011—300 Bloom; exp. no. LA010—175 Bloom; and exp. no. LA013—80–120 Bloom).

Figure 7

SEM image of freeze-dried microcapsules prepared with different gelatin grades: (a) experiment no. LA011, manufactured with gelatin, approx. 300 Bloom—100×; (b) experiment no. LA010, manufactured with gelatin, approx. 175 Bloom—100×; and (c1) experiment no. LA013, manufactured with gelatin, approx. 80–120 Bloom—100× and (c2) 500× magnification.

Figure 8

The FT-IR spectra of oil-free microcapsule (PL), gelatin (GE), gum arabic (GA), microcapsules prepared with three different gelatin grades (LA010, LA011, and LA013), and essential oil (LEO).