Determination of optimal ultrasound conditions for preparation of O/W emulsions with encapsulated juniper berry essential oil (Juniperus communis L.)
The microencapsulation of essential oils can provide their evaporation and oxidation protection, flavor retention or/and masking of unpleasant taste. The microencapsulation process involves emulsions preparation and drying of the obtained emulsion droplets. The aim of this study is the dete...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Faculty of Technology, Novi Sad
2019-01-01
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| Series: | Acta Periodica Technologica |
| Subjects: | |
| Online Access: | http://www.doiserbia.nb.rs/img/doi/1450-7188/2019/1450-71881950023B.pdf |
| Summary: | The microencapsulation of essential oils can provide their evaporation and
oxidation protection, flavor retention or/and masking of unpleasant taste.
The microencapsulation process involves emulsions preparation and drying of
the obtained emulsion droplets. The aim of this study is the determination
of optimal conditions for preparation of the stable O/W emulsions containing
juniper berry essential oil with minimal droplet size, as a preparatory
stage for microcapsule formation. As the first step for pre-emulsions
preparation, homogenization at 10000 rpm for 5 min. was chosen, which gave
emulsions with droplet size between 1.82 and 2.51μm, depending on
concentrations of the surfactant (Tween 20) and encapsulated essential oil.
The second step was ultrasound emulsification during 5 minutes at a
frequency of 99%, using pulsed 10:10 s (ON/OFF) ultrasound treatment, which
was chosen as an optimal, creating emulsions of droplet sizes of 320 nm in
diameter (for 5% essential oil and 1% Tween 20). The addition of wall
material changed the size and stability of emulsions, which depends on type
of biopolymer and its surface competition with used surfactant. The
maltodextrin (MD), gum arabic (GA) and their mixture in equal ratio were
used. GA emulsions can be singled out as the most stable without used
surfactant, with D4,3 = 1.11 ± 0.003 μm. Using MD as a wall material
requires addition of surfactant (1% w/v) to form stable emulsions. The
mixture of MD/GA can be used with or without surfactant. The addition of
Tween 20 (1% w/v) decreases droplet size from 14.86 to 0.99 μm, while
utilization of the ultrasound contributes to the droplet size decrease and
emulsions stability. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 46010] |
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| ISSN: | 1450-7188 2406-095X |