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. 2025 Jul 13;13(7):e70604.
doi: 10.1002/fsn3.70604. eCollection 2025 Jul.

Characterization of Microencapsulated Thymus schimperi Essential Oil Prepared by Spray and Freeze-Drying Using Gum Arabic as Carrier Material

Yisgedu Asres  1   2 , Ariaya Hymete  3 , Habtamu Admassu  4   5 , Amare Ayalew  6
Affiliations

Characterization of Microencapsulated Thymus schimperi Essential Oil Prepared by Spray and Freeze-Drying Using Gum Arabic as Carrier Material

Yisgedu Asres et al. Food Sci Nutr. .

Abstract

The process of microencapsulation is used to coat essential oils that are vulnerable to oxidation, dampness, UV light, and high temperatures. It serves to shield the active chemicals from the environment while boosting the core material's controlled release, stability, and solubility. This work used spray and freeze-drying procedures to microencapsulate essential oil extracted from Thymus schimperi (T. schimperi) leaves using hydro distillation. The objective of this study was to investigate the impact of gum Arabic as a coating agent on the physicochemical properties of T. schimperi essential oil microcapsules through spray and freeze-drying encapsulation procedures. Water content, surface morphology, solubility, bulk density, tapped density, surface oil, flowability, particle mean diameter, and other physical and chemical properties were examined. The physico-chemical properties of the microencapsulated samples were examined, including their releasing property, functional group identification, thermal property, and storage stability. The features of microcapsules made by spray drying differ greatly from those made by freeze drying. According to the results, spray drying was shown to have a higher encapsulation efficiency (71.05%) than freeze drying (68.89%). The solubility index of spray-dried microcapsules was higher than that of freeze-dried microcapsules. When compared to freeze-dried encapsulated T. schimperi EO, the bulk density of spray-dried encapsulated EO is lower, whereas the tapped density is reversed. Compared to freeze-dried microcapsules, spray-dried microcapsules had a more spherical shape.

Keywords: Thymus schimperi; freeze drier; gum Arabic; microencapsulation; morphology; spray drier.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

FIGURE 1
FIGURE 1
Scanning electron microscopic photographs of microcapsules (A) for spray and (B) for freeze dried powders.
FIGURE 2
FIGURE 2
Particle size distribution of spray and freeze‐dried microcapsules.
FIGURE 3
FIGURE 3
FTIR spectrum. FD, freeze‐dried microcapsules; Gum, Gum Arabic; SD, spray‐dried; TEO, thyme essential oil.
FIGURE 4
FIGURE 4
TGA curve of spray‐dried and freeze‐dried encapsulated Thymus schimperi essential oil.
FIGURE 5
FIGURE 5
Cumulative oil release graph of spray and freeze‐dried Thymus schimperi essential oil microcapsule.
FIGURE 6
FIGURE 6
Storage stability of spray and freeze‐dried powder.
FIGURE 7
FIGURE 7
Linear curves of changes in % of DPPH scavenging values during storage in first‐order reaction.
See this image and copyright information in PMC

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