mechanical & solvent extraction of essential oil.pptx

Food chemistry

1. ESSENTIAL OIL

2. ESSENTIAL OIL   Concentrated, plant derived extracts, characterized by their volatile and aromatic properties, used as flavorings, preser vatives, and nutritional enhancers in food products.

3. MECHANICAL EXTRACTION METHODS Cold pressing Screw pressing Hydraulic pressing Pelatrice method Scarification method

4. COLD PRESSING Cold pressing, also known as expression, is a common method for extracting essential oils from citrus fruits such as oranges, lemons, limes, grapefruits, and bergamots. This technique involves mechanically pressing the peels or rinds of the fruit to release the essential oil, without the use of heat or chemicals, which helps preserve the oil's natural aroma and properties . Process of Cold Pressing Essential Oils: Preparation : The fruit peels are washed thoroughly to remove any pesticides or impurities. The outer layer of the fruit (the peel or zest) is typically used because this part contains the oil glands. Puncturing or Scoring : The fruit peels are punctured or scored to rupture the oil sacs in the rind. Pressing : The punctured peels are mechanically pressed or squeezed, releasing the essential oils along with water and other juices from the fruit.

5. Separation : The liquid mixture (oil, juice, and water) is centrifuged or allowed to sit so that the essential oil can separate from the water and other components, since oil is lighter and will rise to the top. Collection : The essential oil is skimmed off and collected for use.

6. SCREW PRESSING Screw pressing, also known as expeller pressing, is a method where a screw press applies high mechanical pressure to the plant material, usually seeds or kernels, to extract oil. This is done without the use of heat (although some friction heat may occur). Steps : Feeding Plant Material : The seeds, nuts, or kernels are fed into a machine with a rotating screw that grinds the material. Mechanical Pressure : The screw presses the plant material against a stationary barrel, forcing out the oil. Separation : The oil is collected as it is expelled from the solid plant matter (which remains as a press cake). Common Uses : Commonly used for extracting oils from seeds and nuts, such as sunflower, sesame, and flaxseed oil.

7. HYDRAULIC PRESSING Hydraulic pressing involves applying high pressure through a hydraulic press to squeeze oil from the plant material. It is similar to screw pressing but often uses more controlled pressure and is suitable for higher-quality extractions. Steps : Preparation : The plant material, usually seeds, is cleaned, ground, and sometimes heated slightly to loosen the oils. Pressing : The material is placed between metal plates and high pressure is applied hydraulically to extract the oil. Separation : Oil is collected from the press, and solid residue is left behind Common Uses : Typically used for seeds and nuts like almond oil or olive oil, and also in cases where high-quality oil is desired.

8. PELATRICE METHOD This is a specialized mechanical method mainly used for citrus oils. It involves peeling the outer layer ( flavedo ) of the citrus fruit, which contains oil glands, followed by extraction of oil through pressing or grinding. Steps : Peeling : The fruit’s outer layer is mechanically removed. Grinding or Pressing : The flavedo is ground or pressed to extract the oil. Centrifugation : The oil and juice mixture is separated by centrifugation Common Uses : Used specifically for citrus oils like lemon, lime, and orange.

9. SCARIFICATION METHOD This is an older, traditional method for extracting essential oils from citrus fruits. In this method, a tool with small sharp projections is used to puncture the peel of the fruit to release essential oils. Steps : Piercing : The fruit is rolled over a metal bowl with sharp points that puncture the oil glands in the peel. Collection : The essential oil is collected in the bowl. Common Uses : Traditionally used for citrus oils but not widely used today due to its labor-intensive nature.

10. SPINNING CONE COLUMN EXTRACTION This is a relatively modern technique that uses centrifugal force to extract essential oils. Plant material is spun at high speeds, and the oil is extracted by mechanical means, aided by water or steam. Steps : High-Speed Spinning : The plant material is placed in a spinning cone column. Oil Separation : The centrifugal force separates essential oil from the plant material. Common Uses : Used in the flavor and fragrance industry, particularly for food-grade essential oils.

11. ADVANTAGES: No chemicals or solvents are used Environmentally friendly Retains natural aroma and compounds High quality oils DISADVANTAGES: Low yield Limited plant material Chance of contamination Time consuming

12. SOLVENT EXTRACTION

13. Solvent extraction Solvent extraction is a method used to extract essential oils from delicate plant materials that are not suitable for steam distillation or mechanical extraction. This process is commonly employed when the plant material is too fragile to endure the high heat involved in distillation, or when a higher yield of oil is desired. Solvent extraction is particularly useful for flowers and aromatic plants, such as jasmine, rose, and vanilla.

14. PROCESS: Plant Material Preparation : The plant material, such as flowers, leaves, or seeds, is collected and sometimes dried to reduce water content, depending on the type of material and oil being extracted. Mixing with Solvent : The plant material is immersed in a non-polar solvent like hexane, ethanol, or methanol. These solvents are chosen because they dissolve the aromatic compounds (essential oils) as well as other constituents such as waxes and pigments from the plant material. Solvent Contact and Extraction : The solvent penetrates the plant tissues and dissolves the essential oils. The mixture is left for several hours or even days to allow the solvent to absorb the aromatic compounds :

15. Filtration : After the extraction period, the plant material is separated from the liquid mixture through filtration or decanting. The solvent now contains a mixture of essential oils, pigments, waxes, and other non-volatile substances. Solvent Removal : The solvent is evaporated, typically under reduced pressure (vacuum) to protect the temperature-sensitive compounds from heat degradation. This leaves behind a waxy, fragrant substance known as concrete . Processing of Concrete : The concrete, which contains essential oils along with waxes and other plant compounds, is further treated with alcohol (usually ethanol) to separate the essential oils from the waxes. The alcohol dissolves the oils but leaves behind the waxes and other non-aromatic components.

16. Production of Absolute : The alcohol solution containing the essential oils is then subjected to a gentle distillation or evaporation process, which removes the alcohol and leaves behind the highly concentrated aromatic oil, called an absolute . Absolutes are considered high-quality essential oils used primarily in perfumery and aromatherapy. Commonly Used for: Solvent extraction is especially popular for flowers and delicate plant materials such as: Jasmine Rose Mimosa Tuberose Oakmoss It is also used when the aromatic compounds are too fragile or volatile to withstand the steam distillation process.

17. ADVANTAGES: Higher yield Preservation of fragile aroma No water required Suitable for non volatile compounds Highly concentrated product DISADVANTAGES: High cost Complex Process Not suitable for therapeutic use

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