Aromatic plants: from extraction to analysis

Transcription

1 Aromatic plants: from extraction to analysis Thierry TALOU Agro-industrial Chemistry Laboratory National Polytechnic Institute of Toulouse ENSIACET 4 allée Emile Monso Toulouse

2 Olfactory system

3 Olfactory system

4 Olfactory system

5 Base Materials ζ Aromatic plants ψflowers, fruits, herbs, spices, roots, seeds, wood, leaves,

6 Extraction of aromatic compounds ζ Methods for extraction of organic odorous compounds are based on 2 physico-chemical properties of aromatic molecules: low polarity high volatitily

7 Main extraction methods ζ Volatility: methods based on HeadSpace or on vacuum distillation ζ Polarity: methods based on solvent extraction ζ Volatility & Polarity : methods based on steam distillation ou Simultaneous Distillation- Extraction

8 Main extraction methods ζ Maceration /»Enfleurage» ζ Cold expression ζ Hydrodistillation/fractionnation ζ Extraction by volatile solvents ζ HeadSpace extraction ψstatic headspace (SPME) ψdynamic headspace (trapping)

9 Main extraction methods

10 Hot Maceration Old process for flowers not producing perfume AFTER pickling Rose Orange flower Absolute of pomade

11 Cold «Enfleurage» Flowers supporting badly heating and keeeping their perfume AFTER pickling Jasmine Tubéreuse Absolute of pomade

12 ζ This process is ONLY applied to citrus familly (lemon, orange, ) Cold Expression

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14 Hydrodistillation : method based on steam distillation Could be used on the differents parts of plants resisting to heating Principle : Hydrodistillation is based on evaporation followed by condensation of liquids Alambic Essencier

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17 Florentin flask

18 Extraction by volatile solvents For plants sensible to heating AND giving consequent extraction yields Vegetable Matter Extractor Washing with solvent (hexan) Decantor / Concentrator Partial Distillation Odorous molecules, waxes and dyes Solvent to re-use Resinoïd : from processing of dry plants Concrete : from processing of fresh plants Absolute : resinoid or concrete washed several times with ethanol and cold filtered

19 Trapping of leaving flower odor by using HeadSpace technique

20 Static HeadSpace analysis Fiber support Silica Fiber Stationary phase ζ Solid Phase Micro Extraction (SPME) ψ adsorption of headspace volatiles at the surface of the fiber ψ Direct injection on a classical GC injector Vial HeadSpace Fiber Sample (liquid or solid) Fiber characteristics: -PDMS (polydimethylsiloxane) : general use -CAR/PDMS (Carboxen/polydimethylsiloxane) : traces analysis - CW/DVB (Carbowax/divinylbenzene) : polar compounds analysis Problems : Variability between fibers Life time: 50 desorptions

21 Analysis of components ζ Gas Chromatography (GC-FID) ξ Obtention of aromatic profiles (Finger Print) ξ Pre-Identification by using Kovats Index or Retention Index determined on polar AND ξ Quantification by intern standart method ζ High Pressure Liquid Chromatography (HPLC) ξ Example:Titration of piperine in pepper

22 Analysis of components

23 Typical GC profile of Essential Oil

24 Identification & Authentification ζ Gas chromatography coupled to mass spectrometry ψ Identification: comparison of mass spectra obtained with data bank ψ Various ionization modes: Electronic Impact, Chemical Ionization ζ Chiral chromatography (mono or bi-dimensionnal) - FID ψ Determination of the naturality of chiral compounds ONLY (enantiomers have NOT the same odor: carvone, menthol,..) ζ Gas chromatography coupled to isotopic mass spectrometry ψ Determination of the naturality of ALL components

25 Gas Chromatography coupled to Olfactometry: GC-O ζ Gas chromatography coupled to olfactometry is a technique presently widely used in aromatic industry which couple instrumental analysis to sensory analysis. ζ The sniffing consists to identify the odor associated to the peaks during the chromatographic separation ζ The objective is to determine the key odor compounds of an aromatic extract by providing either qualitative (descriptive) nor quantitative (scaled) sensorial data

26 What is the interest to «sniff» odors at the end of the GC column? ζ Volatility # odorous activity ζ Human nose is more sensible than GC detector ζ The odor human thresholds are VERY different to the instrumental detection thresholds : factor from one compound to another. ζ All the identified compounds by instrumental methods do not contribute identically to the overall odor of the product

27 Gas Chromatography coupled to Olfactometry (sniffing) 1 fruity 1 - Aromatic extract 2 - Chromatograph 3 - Sniffing Port 4 - Panelist 5 - Computer 6 - Voice Recorder

28 Chromatogram GC-FID Aromagram of detected compounds at the sniffing port

29 Odors descriptors ζ Classification of perfumes (CFP) ζ The Field of Odors (J.N. Jaubert 1984) ζ Data base of T.E. Acree ( ζ Descriptors of Aldrich ζ Descriptors of Firmenich ζ Reference Book of S. Arctander (ISBN ) ζ Lexicon of G.V. Civille et B.G. Lyon (ISBN ) ζ AFNOR standards (définition of vocabulary for sensorial analysis)

30 Odors descriptors

31 Odors descriptors

32 Formulation? After the mandatory analytical step, the flavorist or the «NEZ» has now informations on the hundreds of molecules identified in the plant and to be used for formulating the corresponding flavoring «Tous les chemins mènent... Arôme», P.Duby & E.Bôlcs, FIS. Formulation MUST Determine these factors The key flavor compounds are chemically and sensorially identified What are their REAL ratios? Do synergic effects exist?

33 Formulation by using the Perfume Organ After selecting among hundreds of compounds the genuine odors, their association in precise ratios is the key factor for designing the best flavoring or perfume. Analogy with painting and music «Note», «accords», «nuances», «palet», «organ» of base materials ζ Essential Oils ζ Aromatic Extracts ζ Synthetic Molecules