essential oil 7

8/12/2019 Essential Oil 7

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Technology of Essential Oil (7)

Nur Hidayati


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Technology for essential oil

production

Raw materials pre-treatment

The change of physical chemical properties

of essential oil during preparation

Production technology

Purification technology


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1. Chopping

To assure the quality of essential oil , raw material should be in

good condition. Essential oils in the plant is surrounded by the oil

glands, vessels (very small pipe), oil sacs or glandular hairs. If the

material is left intact, then the essential oils can only be taken if

the water vapour / solvent is able to go the system and pushthem to the surface (hydro diffusion). Rate of picked oil is

determined by the rate of diffusion processes. Therefore, the

raw material should be treated to get the oil as much as possible.

With chopping, it is expected to open or damage the oil glands.


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Since the purpose of chopping to facilitate the

evaporation of essential oils from the material, thereforeafter the material is cut / on rollers into small size, theyshould be distillated as soon as possible.

Chopping can have bad effects:

Reduce the yield of oil, due to some oil evaporateduring and after chopping.

Oil composition will change and will affect the odours.

Essential oils consist of several components that havedifferent boiling points. Loss of components having lowboiling point affect the composition of essential oils


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2. Materials Storage

Storage of raw material before chopping can affect the

yield of oil but its effects is not so serious compared to

chopping effect. Storage is usually carried out due to

distillation obstacle or the capacity of distillation vessel islow. Storage in long period is able to reduce the oil yield

because of oxidation and polymerisation process. If the

materials must be stored before next process, they

should be store in dry air, low temperature, not exposedto sunlight, and in uncirculated air. Therefore yield

reduction can be minimized.


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Factors affecting the loss of essential oils during thestorage of dry materials:

Materials condition

Method and duration of storage Essential oil component

General rules:

Flowers, leaves, and herbs should not be stored in longtime period. Seeds, peels, rhizomes, roots and woods areable to be stored longer (depend on storage method).


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3. Withering and drying

Withering and drying can reduce the oil in plants. Parts ofplants with high water content can be loss of volatile oilcontent in large numbers when dried in the open place.

The loss of essential oils during the withering and drying

of plant material is much greater than the loss ofessential oils that occur during storage of plant materialafter drying. In the early stages of withering and dryingplants still hold a large amount of water in the cells. Bydiffusion, water transport essential oil go to the surface

and helps the absorption. When the dew of water is lostand the plants are dry, then hydrodiffusion is not happenagain.


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The change of physical chemical properties of essential oil

during preparation

Essential oils produced from wet or dry plants showed the

different in chemical-physical properties and composition.

Especially essential oils derived from flowers, leaves, rhizomes

and roots, which in the wet state they contain a lot of water.

Essential oil from wet roots is more soluble in alcohol 70% than

that of from dry ones. Solubility of essential oil is reduced to

storage time. During the withering and drying, the membrane of

cells will gradually burst, the water penetrate from one cell to

another to form a volatile compound. Examples: whenharvested, fresh patchouli leaves are not smell, but the smell will

appear when the leaves are dried or stored.


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Production Technology

1. Distillation

Direct steam (water and steam distillation)

Indirect steam

Simple steam

2. Extraction

Extraction using solvent

Extraction using oil/fat

Wet oil/fat

Hot oil/fat

3. Expression process of sponge

Process of cuelle piquer

Process using abrasion machine

4.Special process


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Distillation

Equipments:

1. still

2. Condenser3. Decanter

4. Boiler


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Direct steam distillation (water and steam)

To produce essential oil from leaves, stem and

rhizomes. Example: clove leaf, patchouli leaf, betel

leaves, clove flower stalks, rhizomes of ginger and

lajagua.

Direct steamsteam that produced directly heat up

raw material


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The kettle used in the direct steam distillation is avessel equipped with perforated tray. This tray is

to separate the water with raw materials. Thebottom part is to boil the water, the height isabout a third of the kettle. The top of the kettle isused to put raw material to be distilled. When thekettle is heated, water vapour from the bottom ofthe kettle goes up through the perforated trayand the crevices of the materials. Essential oilscontained in the materials will be carried on bysteam and will be drained to the condenser. In

the condenser, the water vapour and essential oilare cooled and condensed, then collected in theseparator tank (decanter).


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The benefit:

cost for equipment is less/ cheaper because ofsimple equipment. This method is usedcommercially.

The weakness:The kettle is not able to produce steam in largequantity because the volume of water is limited.Usually the kettle is modified by recycling

separated water from decanter to the bottompart of kettle. This method can increase the yieldand to prevent lack of water caused burnt smell.


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To produce usually raw material from stem or

wood and seed. Example: cinnamon bark,

masoyi and gaharu.

The working principles is similar with the

direct method but the steam is produced

separately in a boiler. Steam is flown from a

boiler to the kettle.

Indirect Steam Distillation


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To produce the max result, raw material should be dried to

reduce the water content up to 15%, then it is cut/chopped to

make easily hydrodiffusion.

Raw material is fed to the kettle about 75% of full capacity and it

is not too tight or too slack.

This system can be started at low pressure (around 0,5 bar).

Then pressure in increased gradually up to 2 bar (especially for

vetiver (akar wangi) up to 3 bar) to get the essential oil out. If

the pressure is high at the beginning , chemical component can

be damage. When the all high volatile essential oil evaporate,

the pressure is increased to get the higher boiling point essential

oil.


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Jika hendak menerapkan sisitem ini, idealnya harus

menghitung volume uap panas yang dibutuhkan. Caranya

dengan mengukur volume uap air rata-rata yangdikondensasikan per menit (1 kg air per menit). Selain itu

juga mengukur kemampuan uap panas membawa minyak.

Misal setiap menit 1 kg uap panas membawa 0,5% minyak.

Keuntungan penyulingan dengan menggunakan boiler ini

adalah

waktu penyulingan yang relatif singkat (5-6 jam)

dibandingkan sistem penyulingan lain (12-14 jam)

mampu menyuling beberapa bahan baku pada ketel-

ketel yang terpisah secara bersamaan.


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Simple Steam Distillation

Plant material is immersed directly in a still filled withwater. This is then brought to a boil.

Heterogeneous vapours are condensed on a coldsurface.

Essential oil separates based on difference in densityand immiscibility.

This system is the simplest method compared to

others.

It is suitable for less quantity raw materials.

Water-raw material ratio is about 3:1.


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Simple steam distillation has some weakness:

Time is longer

The yield and quality are lower due to lots of oil is not

extracted.

It can conduce the oxidation process.

Some comodities used this method are ginger , palmarose,

and basil.


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Should be known:

1. Distillation Length

Length of distillation is depend on raw material. Some materialsrelease immediately the oil, oppositely some need longer time.

For example: lemongrass requires 3-4 hours, ginger 6 hours and

nutmeg 12 hours. Moreover, technology also affect the distillation

time.

Materials Length (hr) T (oC) and P (atm)

Pathcouli 5 3 jam (first) 105 oC & 1 atm

2 jam (the next) 130 oC & 2 atm

Nutmeg 12 105 oC & 1 atm

Gaharu 10 160 oC & 3 atm

Ginger 6 105 oC & 1 atm

vetiver 14 140 oC & 1.8 atm

Lemongrass scented 4 105 oC & 1 atm

cananga 14 105 oC & 1 atm


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2. The Yield .

Final volume of oil data is required to stop the distillation . For

some materiasl having high boiling point, the distillation can be

extend for a while to get the high fraction. Example: vetiverol in

vetivera , patchoulen in patchouli leaves and santalol insandalwood.


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Factor affecting the distillation process:

Diffusion or movement of the essential oil due

to hot water through glandular

(hydrodiffusion)

Hydrolisis of oil component

Decomposition of oil component

essential oil 7

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