Organic Agricultural Sciences UNIKASSELDepartment of Agricultural Engineering

Distillation technologyDistillation technologyof essential oil cropsof essential oil crops

Dipl.-Ing. Kai SvenssonDipl. Ing. Kai Svensson

Contents:

1 Introduction – definition and market information

1.1 Botany and physiology of essential oil crops1 2 Chemistry and quality of essential oils1.2 Chemistry and quality of essential oils1.3 Main uses of essential oils

2 Production of essential oils – distillation technology

3 Example: Helichrysum italicum project Corsica island

1 Introduction1 Introduction

Natural essential oils are obtained straight from the plant and t difi d h i ll h i ll ft dare not modified physically or chemically afterwards.

tifi i l il i hi ith l f itartificial oils > enriching with one or several of its components

synthetic oils > produced by combining chemically synthesised componentssynthesised components

Essential oils are:Essential oils are:

volatile constituents of plant material- volatile constituents of plant material

responsible for the characteristic odour of the plant material- responsible for the characteristic odour of the plant material

i t f h i l titi f i t f h i l t- mixtures of chemical entities of a variety of chemical types

ll l i iti- generally complex in composition

Some two hundred essential oils are produced and traded internationallyp y

Volumes range from 20-30,000 tonnes to less than 100 kg

Prices vary widely

but for the majority of oils fall within the range of US$4 $60/kg- but for the majority of oils fall within the range of US$4-$60/kg - for specialist minor oils the price can be many 1000 of US$/kg

E ti ti ld d ti d t d f ti l il i f ht ithEstimating world production and trade of essential oils is fraught with difficulties

Th E U i i th ld’ bi t i t f ti l ilThe European Union is the world’s biggest importer of essential oils (with France, Germany and UK being the major importing countries)

Th USA i th ld’ l t i ti t f ti l ilThe USA is the world’s largest importing country of essential oils followed by Japan

Source: ISO/TC 54 Business plan (2004)

The trade distribution for essential oils and oleoresins have a number of routes to market.

Source: Herbs, spices and essential oils Post-harvest operations in developing countries. UNIDO and FAO (2005)

1.1 Sources of natural essential oils –

botany and physiology of essential oil cropsy p y gy p

Essential oils are widely distributed over plant families

Some 4,000 plant species contain essential oilscontain essential oils

Only a few hundred of them have sufficient concentrationshave sufficient concentrations to allow extraction of essential oils

Quantity of essential oil varies

The primary products harvested for spice orharvested for spice or essential oil production can be divided into categories

Plant organsPlant organs containing natural essential oils are illustrated in Figure 3.

Source: Extraction Technologies for Medicinal and Aromatic Plants . CS-UNIDO (2008)

Synthesis & accumulation of essential oils are generallyessential oils are generally associated with the presence of specialized histological str ct res depending pon thestructures depending upon the plant family

Specialized plant structures that produce and storethat produce and store essential oils are shown in Figure 4

Source: Extraction Technologies for Medicinal and Aromatic Plants . CS-UNIDO (2008)

Function of the essential oils for the plant:

Attracting (help polination) or repelling insectsA tib t i l tAs antibacterial agentsComunication

1 2 Ch i l ti d lit f ti l il1.2 Chemical properties and quality of essential oils

An essential oil can contain dozens or even hundreds of componentscomponents

> particular taste or fragrance

A gas chromatography laboratory test is needed to determine the percentage of each constituentdetermine the percentage of each constituent

Essential oils are highlyEssential oils are highly complex chemical compoundsp

> consist of >

Source: Extraction Technologies for Medicinal and Aromatic Plants . CS-UNIDO (2008)

Physical properties of essential oils:Physical properties of essential oils:

Volatile and liquid at room temperature- Volatile and liquid at room temperature- Less dense than water (with exceptions)

refractory index- refractory index- soluble in alcohol, fat oils, organic solvents, high grade alcohol

li l bl d t l bl i t- lipo-soluble and not very soluble in water

Variability factors of essential oils compounds:Variability factors of essential oils compounds:

Occurrence of chemotypes I fl f th t ti lInfluence of the vegetative cycleInfluence of environmental factorsI fl f ti th dInfluence of preparation method

Chemotype = variation in chemical composition of anChemotype = variation in chemical composition of an essential oil of the same species

Thyme (Thymus vulgaris) has 6 different chemo-types depending on which is the main component

- timol, carvacrol, linalool, geraniol, tuyanol -4, or terpineoltimol, carvacrol, linalool, geraniol, tuyanol 4, or terpineol

Named using the name of the species followed by the i t f it h tmain component of its chemotype.

Thymus vulgaris linalool Thymus vulgaris timolThymus vulgaris linalool, Thymus vulgaris timol.

Composition of essential oils depends/varies from:p p

- plant geneticson place of origin- on place of origin

- growing conditions- cultivation practices

t f h ti- moment of harvesting- extraction methods- time of day-- temperaturetemperature-- humidityhumidity-- duration of daylightduration of daylighty gy g-- radiationradiation-- fertilizationfertilization-- watering regimentwatering regimentwatering regimentwatering regiment- amount of sun- type of soil-- ......

1 3 Main uses of essential oils1.3 Main uses of essential oils

Essential oils find a use in a variety of industries

Essential oils are used in a wide variety of consumer dgoods

spices (essential oil plants) have been added tospices (essential oil plants) have been added to foodstuffs not just for flavouring but to help preserve them

PharmacyPerfumeryPerfumeryFood technology Starting materials to synthesize other compounds AntisepticPreservativeAromatherapy

S H b i d ti l il P t h tSource: Herbs, spices and essential oils Post-harvest

operations in developing countries. UNIDO and FAO (2005)

2 Production of essential oils – distillation technologydistillation technology

Hi t i ll th fi t d f di till ti t k l i thHistorically, the first record of distillation took place in the lndus Valley in what is now known as Pakistan around 5000 years ago (ca 3000 B C )5000 years ago (ca. 3000 B.C.)

Distillation Fundamentals:Distillation Fundamentals: > an excellent discussion of these are given in a recent

publication of Denny (1991)publication of Denny (1991)

- Interrelationships between the First and Second Laws of pThermodynamics, Latent Heat and Vapor Pressure

Th l th t d ib th b h i f id l b d t- The laws that describe the behavior of ideal gases can be used to approximately describe the behavior of vapors.

Production technology is an essential element to improve the overall yield and quality of essential oil

There are five main methods of extraction:1. • Expression2. • Hydro- or water-distillation.

W t d t di till ti3. • Water and steam distillation4. • Steam distillation5 • Solvent extraction5. • Solvent extraction

The extraction of essential oils from plant material can be achieved by a number of different methodsy

Source: Extraction Technologies for Medicinal and Aromatic Plants . CS-UNIDO (2008)

Steam distillation in a still is the most common extraction methodmethod

The aromatic parts of the plant are placed in a still through p p p gwhich steam is passed

A ti ll l i th l l f ti l ilAromatic cells releasing the molecules of essential oils

The blend of steam and oil then passes through a condenserThe blend of steam and oil then passes through a condenser

From the condenser distillate flows into a separator where oil t t ti ll f th di till t tseparates automatically from the distillate water

H d di till ti f l t t i l i l thHydrodistillation of plant material involves the following main physicochemical processes:

Hydrodiffusion: Diffusion of essential oils and hot water through plant membranesthrough plant membranes

Hydrolysis in the present context is defined as aHydrolysis in the present context is defined as a chemical reaction between water and certain constituents of essential oils.

Decomposition by heat: Almost all constituents of p yessential oils are unstable at high temperature.

Items of a distillation assemblyItems of a distillation assembly

Site choiseTh till b dThe still bodyThe energy source Th d i t (h t h )The condensing sytem (heat exchanger)The oil seperator (florentine vessel)Labour saving devicesPurification and storage requirements

There are three types of hydrodistillation for isolating essential oils from plant materials:essential oils from plant materials:

1 Water distillation1. Water distillation2. Water and steam distillation3 Direct steam distillation3. Direct steam distillation

Source: Herbs, spices and essential oils Post-harvest

operations in developing countries. UNIDO and FAO (2005)

S H b i d ti l il P t h tSource: Herbs, spices and essential oils Post-harvest

operations in developing countries. UNIDO and FAO (2005)

S H b i d ti l il P t h tSource: Herbs, spices and essential oils Post-harvest

operations in developing countries. UNIDO and FAO (2005)

The final quantity and quality of the product depend on f l i icareful monitoring

the temperature and pressure inside the still- the temperature and pressure inside the still

- and to an even greater extent on the quality of the plants g q y pused, which must be picked at the right moment.

3 Example: Helichrysum3. Example: Helichrysum italicum project on Corsep j

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L d h di i l d f C i hLocated on the mediterranean island of Corsica, the "Bordeo„ farm is specialised in cultivation, distillation and extraction of aroma- and medicinal plants.extraction of aroma and medicinal plants.

The aromatic plants are either grown on the farm and p gtherefor organic certified with the label "Demeter" (Lemon verbena, Laurel, Rosmary, Hamamelis, Rose, Clementine and Lemon leaves Eucalyptus)Clementine – and Lemon leaves, Eucalyptus),

oror,

they are collected in the wild and certified organic by y g yEcocert (Italian Everlasting, Fragrant Aster, Myrtle, Corsican Pine,…).

The genus Helichrysum (family Asteraceae) from theThe genus Helichrysum (family Asteraceae) from the tribe Inuleae comprises more than 400 species widespread throughout the world.p g

Helichrysum italicum (Roth) G. Don, a typicallyHelichrysum italicum (Roth) G. Don, a typically Mediterranean species, is an aromatic shrub (50-70 cm high) with yellow flowers (blossoming time, May-June) growing on dry cliffs and sandy soil.

The cultivation of Helicrysum italicum, known as Immortelle, was developed since 2004 in Corsica by E N t ll C i t hi ithEssences Naturelles Corses in partnership with L’Occitane en Provence.

The technical support was provided by Civam Bio Corse (regional organic farming organism) and PAM' INNOV(regional organic farming organism) and PAM INNOV (aromatic plant expert).

This work made it possible to define a mechanized way of cultivation in conformity with the conditions of yEuropean organic farming.

P i i l f h f l i iPrinciple of the contracts of cultivation:

The objective of these contracts is to guarantee to the whole of the signatories a durable cooperation over atwhole of the signatories a durable cooperation over at least 5 years of production.

Price stability and security of the market.

Guarantee of the Corsica origin of the plant and specific quality of essential oil.

Respect of the environment and safeguarding of natural spaces.spaces.

H italicum oil is widely used in perfume industry andH. italicum oil is widely used in perfume industry and aromatherapy for their flavouring properties and biological activities (anti-inflammatory, anti-bacterial, anti oxidant)anti-oxidant).

The essential oils of three H. italicum subspecies have e esse t a o s o t ee ta cu subspec es a ebeen studied: subsp. serotinum, subsp. microphyllumand subsp. italicum.

The essential oil of H. italicum has an economic importance in Mediterranean areas particularly for C i I l d d t hi h t f l t tCorsica Island, due to high amount of neryl acetate.

The chemical composition of H italicum essential oilThe chemical composition of H. italicum essential oil showed chemical variability among geographic origins.

Bianchini et al. Flavour Fragrance Journal, 2001, 16, 30-34

Divers chémotypes identifiés:

Corse-Sardaigne: acétate de néryle, nérol, linalol, γ-curcumèneItalie: α-pinène (E)-β-caryophyllène α- and β-sélinèneCroatie: α-pinène, γ-curcumène, β-sélinène,

France continentale: β pinène 1 8 cinéole terpinèn 4 ol β dicétones

Italie: α-pinène, (E)-β-caryophyllène, α- and β-sélinène

France continentale: β-pinène, 1,8-cinéole, terpinèn-4-ol, β-dicétones

Grèce: géraniol, acétate de géranyle, (E)-nérolidol

Composition of Helichrysum italicum subsp. italicum essential oil showed chemical variability according toessential oil showed chemical variability according to vegetation cycle, environment and geographic origins.

M th h i l l hi f thi i iMoreover, the chemical polymorphism of this species is outstanding and its relation with both genetics and environmental factors is not yet well defined.

Investigations on the characterisation of H. italicum oil observed two chemical compositions (high amount of b-observed two chemical compositions (high amount of bdi-ketones or high amount of neryl acetate) according to the vegetation cycle.

These two chemical compositions appeared also to be dependent on the sampling locations.p p g

DP é / Fl iComposés Dormance(hiver)

Pré- / Floraison(été)

16 - 32%20 - 43%acétate de néryle

2 - 3%7 - 8%γ-curcumène

0,1 - 9%0,1 - 3%limonène

12 - 15%2 - 3%cétones

2 - 3%7 - 8%γ-curcumène

1 à 2%3 à 7%β-dicètones insaturées

14 - 18%4 - 10%β-dicètones saturéesBianchini et al. Flavour Fragrance Journal, 2001, 16, 30-34

Some studies have been also reported the influence of soil characteristics on the yield and composition of y pessentials oils from various aromatic plants.

Hence the question is no longer whether soilsHence, the question is no longer whether soils characteristics, vegetation cycles or inorganic plant composition influence essential oil composition but to q antif the relati e contrib tion of each of these factorsquantify the relative contribution of each of these factors.

References Bedi, S.& Tanuja & Vyas, S. P. (2008): A Handbook of aromatic an essential oil plants – Cultivation, chemistry, processing an uses. Agrobios, Jodhpur. Bianchini, A. & Tomi, P. & Costa, J. & Bernardini, A. F. (2001): Composition of

( ) G f f CHelichrysum italicum (Roth) G. Don fil. subsp. italicum essential oils from Corsica (France). Flavour and fragrance journal 2001, vol. 16, no1, pp. 30-34 (36 ref.) Denny, E. F. K. (1991): Field Distillation for Herbaceous Oils. Denny McKenzie Associates, Lilydale, Tasmania 2. Auflage.Dürbeck, K.& Wijesekera, R. O. B.& Ratnatunga, C. M. (1997): The distillation of essential oils. – Manufacturing and plants construction handbook. Protrade, Deutsche Gesellschaft für technische Zusammenarbeit GmbH.Gildemeister, E., Hoffmann, Fr. (1956): Die ätherischen Öle Band 1, 4. Auflage, [H ] Wilh l T ib Ak d i V l B li[Hrsg] Wilhelm Treibs. Akademie Verlag, Berlin.Hüsnü Can Baser, K.& Demirci, F.:(2006): Chemistry of essential oils. In: Berger, R.G. [Hrsg.]: Flavours and fragrances, Seite 43-83. Springer Verlag, Berlin Heidelberg.Oyen, L. P. A. & Dung N. X. (1999): Essential oil plants – Plant resources of south east asia. PROSEA, Backhuys, Leiden. Öztekin, S.& Martinov, M. & Müller (2007): Medicinal and aromatic crops –Harvesting, drying and processing. Haworth Press Inc., Binghamtion, New York.

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