Development of Optimized Origanum vulgare L. Essential Oil-Loaded Chitosan/Gum Arabic Nanocapsules by Complex Coacervation

TL;DR

Researchers developed stable nanocapsules to protect oregano essential oil, which is useful for food applications.

Contribution

A novel nanoencapsulation method using chitosan and gum arabic was optimized for preserving oregano oil's bioactive compounds.

Findings

Optimized nanocapsules had a diameter of 323 nm and high encapsulation efficiency (95%).

The method preserved carvacrol, the main bioactive compound in oregano oil, with structural integrity over 120 days.

Electrostatic interactions between chitosan and gum arabic were confirmed via FTIR analysis.

Abstract

Oregano essential oil (OEO), rich in carvacrol and thymol,
has
bioactive properties but is prone to degradation due to its volatile
nature. Nanoencapsulation by complex coacervation, using chitosan
(CHI) and gum arabic acid (GA), emerges as an alternative to increase
its stability in food matrices. This study investigated the influence
of the CHI/GA mass ratio on the formation of OEO-containing nanocapsules
and quantified the encapsulated carvacrol using validated GC–MS.
A Box–Behnken experimental design optimized the OEO concentration,
CHI/GA ratio, and amount of Tween 80. Physicochemical properties such
as the diameter, PdI, and zeta potential were evaluated. Morphology
was analyzed by SEM and AFM, and thermal stability by TGA and DSC.
Stability was monitored for 120 days at 4 °C, 25 °C, and
40 °C. The optimized formulation (470 mg of OEO, 659 mg of CHI/GA
1:5, and 13 mg of Tween) resulted in nanocapsules with a diameter
of 323 ± 22 nm, a PdI of 0.20 ± 0.02, and a zeta potential
of +15.8 ± 0.8 mV. FTIR analysis confirmed electrostatic interactions
between CHI and GA. GC–MS identified 24 constituents in the
OEO, with carvacrol as the main compound (78.8%). The validated method
showed an R
2 of 0.9976, proving to be
specific, precise, and accurate. The encapsulation efficiency was
95% ± 0.7, indicating that the technique preserved the oil’s
composition and concentration. The nanocapsules maintained stability
under different temperatures with confirmed structural integrity.
It is concluded that nanoencapsulation via complex coacervation, combined
with experimental design, allows for the production of stable and
effective nanocapsules for the delivery of lipophilic bioactive compounds.
The validated analytical method reinforces the system’s applicability
in future research and the development of functional products.

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