Phytochemistry I Lecture 2: Preparation Methods
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Questions and Answers

What is the main purpose of scarification and expression methods?

  • To increase the boiling point of oils
  • To enhance the color of the fruit
  • To liberate oil from plant material (correct)
  • To create a solid extract from fruits

Which of the following fruits is primarily used in the sponge method for oil extraction?

  • Lemon
  • Bergamot
  • Grapefruit
  • Orange (correct)

What does the ecuelle-à-piquer method utilize to extract oil?

  • A convex projection
  • A sponge soaked in oil emulsion
  • A funnel-shaped instrument with pins (correct)
  • A mechanical grater

In the expression of rasping process, what is the first step involved?

<p>Removing the outer layer of the peel (B)</p> Signup and view all the answers

What is the main disadvantage of water distillation?

<p>Burning of the plant material. (A)</p> Signup and view all the answers

What is the primary collection method used in the sponge method for oil extraction?

<p>Sponge filtration (A)</p> Signup and view all the answers

What characteristic of the fruits is essential for the successful application of scarification and expression methods?

<p>Presence of oil glands in the peels (D)</p> Signup and view all the answers

Which distillation method allows for modified steam pressure?

<p>Direct steam distillation (C)</p> Signup and view all the answers

Which of the following is a commercial preparation of clove oil?

<p>Cinnamon oil (D)</p> Signup and view all the answers

Which process involves using strong pressing after removing the outer peel?

<p>Expression of rasping process (D)</p> Signup and view all the answers

Which method is most suitable for oils rich in esters?

<p>Direct steam distillation (A)</p> Signup and view all the answers

Which type of oil extraction method is preferred for heat-sensitive oils found in fruit peels?

<p>Scarification and expression (D)</p> Signup and view all the answers

How is the removal of water and moisture typically accomplished?

<p>Filtration over anhydrous sodium sulphate (B)</p> Signup and view all the answers

What is a potential issue with hydrodiffusion in distillation?

<p>It could be affected by uneven charging. (C)</p> Signup and view all the answers

Which distillation method typically provides the highest rate of distillation?

<p>Direct steam distillation (A)</p> Signup and view all the answers

What is a notable advantage of water and steam distillation?

<p>No risk of hydrolysis (B)</p> Signup and view all the answers

What is the primary principle behind the distillation method for preparing volatile oils?

<p>Dalton’s law of partial pressure (C)</p> Signup and view all the answers

Which method of distillation is particularly beneficial for heat-sensitive materials?

<p>Saturated steam distillation (C)</p> Signup and view all the answers

What is one of the main purposes of cohobation in the distillation process?

<p>To enhance the yield of volatile oil (A)</p> Signup and view all the answers

What role does hydrodiffusion play in the distillation of volatile oils?

<p>It facilitates the penetration of water into plant tissue. (B)</p> Signup and view all the answers

What precaution is recommended to minimize hydrolysis during the distillation process?

<p>Comminution just before distillation (D)</p> Signup and view all the answers

Which of the following is NOT a reason why distilled oil may be considered artifacts?

<p>Reduction of energy usage (B)</p> Signup and view all the answers

Which component is essential in the water distillation apparatus used for volatile oil extraction?

<p>Condenser (D)</p> Signup and view all the answers

What effect does insufficient distilled oil boiling at high temperatures have?

<p>Introducing undesirable flavors (B)</p> Signup and view all the answers

What is the purpose of using enfleurage in the extraction process?

<p>To extract oils that cannot be obtained by distillation (B)</p> Signup and view all the answers

Which solvent type is primarily used in the enfleurage method?

<p>Fats like lard and tallow (B)</p> Signup and view all the answers

What is a key characteristic of oils extracted using enfleurage?

<p>They are made from thermolabile constituents (D)</p> Signup and view all the answers

How often should the old flowers be replaced in the enfleurage process?

<p>Every 2-3 days (D)</p> Signup and view all the answers

What is the final product obtained after the enfleurage process?

<p>Floral pomade (B)</p> Signup and view all the answers

Which extraction method is ideal for the preparation of delicate flower oils?

<p>Cold enfleurage (D)</p> Signup and view all the answers

What process follows the removal of the last charge of flowers in enfleurage?

<p>Defleurage (D)</p> Signup and view all the answers

Which of the following is NOT a product of the enfleurage method?

<p>Essential oil (C)</p> Signup and view all the answers

Which method of preparation is best suited for fresh materials rich in volatile oils?

<p>Distillation (A)</p> Signup and view all the answers

What is a key disadvantage of distillation in the preparation of volatile oils?

<p>It may affect heat-sensitive constituents (D)</p> Signup and view all the answers

Which of the following is an advantage of using extraction for volatile oils?

<p>Produces oils with natural odors (B)</p> Signup and view all the answers

Which method is commonly used for oils present in the outer peels of fruits?

<p>Scarification and Expression (B)</p> Signup and view all the answers

What is a major application for supercritical fluid extraction?

<p>Production of floral absolute (C)</p> Signup and view all the answers

What is the primary reason absolutes can be used in smaller concentrations than corresponding concretes?

<p>They are richer in oxygenated constituents (D)</p> Signup and view all the answers

What process is required to liberate volatile constituents from odorless glycosides in plant material?

<p>Hydrolysis (B)</p> Signup and view all the answers

What is a disadvantage of using scarification and expression for extracting oils?

<p>It requires a high number of workers (B)</p> Signup and view all the answers

Flashcards

Scarification

A mechanical process used to extract oil from plant material, involving puncturing and squeezing at room temperature.

Expression Methods

Methods for extracting oils from plants by mechanical pressing. Examples include sponge method, ecuelle-à-piquer, and rasping.

Sponge Method

An expression method for extracting oil from plant peels, using a sponge to collect oil emulsified with water.

Ecuelle-à-piquer Method

A method using a funnel-shaped tool to puncture the plant surface and release oil, collecting it through a tube.

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Expression of rasping process

A method of extracting oil by removing the outer layer of the peel with a grater, collecting the raspings, and pressing them.

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Solvent Extraction

A method of extracting compounds from a solid material by using a solvent.

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Heat Sensitive Oils

Oils that are easily damaged by high temperatures.

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Citrus Fruits

Fruits that are commonly used for extracting oils, examples are orange, lemon, and bergamot.

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Ester Hydrolysis

The chemical reaction of an ester with water to break the ester bond, creating an alcohol and carboxylic acid.

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Tertiary Alcohol Dehydration

Converting a tertiary alcohol into a hydrocarbon by removing a water molecule.

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Unsaturated Terpene Polymerization

Joining multiple unsaturated terpene molecules together to form a larger molecule.

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Oil Purification by Distillation

Using distillation methods to remove impurities from oil, like bad smells or colors, and water.

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Re-distillation in steam

A distillation method used to remove impurities from oil by heating with steam to partially evaporate the oil, then re-distilling.

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Dry Distillation under Reduced Pressure

A distillation method that utilizes reduced pressure to lower the boiling point and purify oil.

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Anhydrous Sodium Sulphate

A chemical compound that absorbs water effectively, used in drying oil to remove moisture.

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Water Distillation

A distillation method for extracting oil from plant materials using water as the heating medium.

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Water and Steam Distillation

A distillation process where steam interacts with the plant material that contains moisture, effectively extracting oil.

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Direct Steam Distillation

Oil extraction method that uses steam directly pumped into the material, more efficient in larger operations.

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Simple Steam Distillation

A method of separating volatile oils from plant material using steam. The oil and steam mixture is then condensed, separating the oil from the water.

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Saturated Steam Distillation

Distillation using steam saturated with water vapor. This method is often used for heat-sensitive materials.

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Hydrolysis

Chemical reaction that breaks down a compound by the addition of water.

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Scarification

The process of breaking down the outer covering of plant material like seeds or fruits.

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Expression

The mechanical extraction of oils from plant material by pressing or squeezing, like pressing olives to extract oil.

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Enzymatic Distillation

A specific method of separating volatile oils that relies on enzymes to break down components that can impede extraction.

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Dalton’s Law of Partial Pressures

The total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas.

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Cohobation

The process of returning the aromatic water (water saturated with volatile oil) from distillation back to the still for further distillation to improve the yield of oil.

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Comminution

The process of reducing plant material to smaller pieces.

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Hydrodiffusion

The process by which water penetrates the plant tissue.

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Distilled Oil Artifacts

Impurities or altered components in the oil, potentially originating from incomplete distillation or high boiling point constituents.

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Solvent Extraction

Method of extracting volatile oils from plant material using a solvent.

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Non-volatile Solvent Extraction

Solvent extraction using non-volatile solvents like fats (lard/tallow).

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Enfleurage Method

Process of extracting delicate flower oils using fat mixtures.

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Enfleurage Product

Fat saturated with floral oil after the process.

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Supercritical Fluid Extraction

Extraction method utilizing special fluids at high pressure and temperature.

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Volatile Solvent Extraction

Solvent extraction using volatile solvents.

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Thermolabile Constituents

Substances easily damaged by heat.

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Delicate Flower Oils

Fragrant oils from flowers present in small amounts and easily damaged by heat.

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Cold Enfleurage

Enfleurage process using a cold fat mixture.

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Hot Enfleurage

Enfleurage process using a hot fat mixture.

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Volatile Oil Extraction

Methods used to extract volatile oils from plant materials, categorized into distillation, solvent extraction, and supercritical methods.

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Distillation (Volatile Oil)

A method for extracting volatile oils by heating plant material, vaporizing the oil, and then condensing it.

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Solvent Extraction (Volatile Oil)

Method for extracting volatile oils using solvents to dissolve and separate the target compounds.

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Supercritical Fluid Extraction

An extraction method using supercritical fluids to isolate specific volatile oils or aromatic components.

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Absolute (Volatile Oil)

A concentrated, alcohol-free, semi-solid product produced from solvent extraction, richer in fragrant molecules compared to concretes.

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Enfleurage

Type of solvent extraction technique.

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Glycosidic Combination (Volatile Oil)

Volatile oils in a plant that are bonded to a sugar molecule. Requires hydrolysis to separate and then further extraction.

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Hydrolysis (Volatile Oils)

Chemical process to break glycosidic bonds, releasing bound volatile compounds.

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Scarification/Expression

Mechanical methods for extracting oils from the peels and outer layers of fruits. Suitable materials rich in volatile constituents.

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Extraction (Volatile Oil)

A method of extracting heat-sensitive volatile oils at room temperature, requiring skilled labor.

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Study Notes

Phytochemistry I, Lecture 2: Methods of Preparation

  • Methods of preparation for volatile oils include distillation, scarification and expression, extraction, and enzymatic hydrolysis.

Distillation Method

  • Depends on Dalton's law of partial pressure.
  • Immiscible liquids boil at a temperature below their individual boiling points when heated together.
  • Types:
    • Simple steam distillation (water distillation)
    • Saturated steam distillation
      • Direct steam distillation
      • Water and steam distillation

Water Distillation Apparatus

  • Consists of:
    • Still (vessel for plant material and water)
    • Condenser (cools and condenses vapor)
    • Receiver (collects volatile oil)
  • Oil is sent for purification processes like removal of solids, water, redistillation, and centrifugation.
  • Hydrosol (water layer)

Cohobation

  • Return aromatic water (water saturated with volatile oil) to the still for redistillation.
  • Improves oil yield.

B-Saturated Steam Distillation (Direct Steam Apparatus)

  • Uses a steam boiler, heating jacket, removable lid, plant material, cooling water, condenser (multi-tube), and oil separator (for oils lighter than water).
  • Separated oil is collected by the oil separator, and the water condensate.

Process Adoption

  • Shortens distillation duration, suitable for heat-sensitive materials.
  • Limits alteration of constituents.
  • Conserves energy.

2-Water and Steam Apparatus

  • Includes a flask with plant (herb) material, for water refills. This is to avoid air pressure issues; it is essential in this method of distillation because it allows consistent boiling of the water and allows for the controlled addition of water to the flask.
  • Water is heated, vapor travels through the condenser, and is distilled into a separating funnel. This is collected at a controlled rate in a 50 ml collecting tube.
  • Cooling water runs into the condenser and out, and the outlet equalizes pressure.

Precautions in Handling the Plant

  • Comminution (crushing) the plant material just before distillation.
  • Wetting of dry plant material.
  • Even packing/charging to enable hydrodiffusion.

Hydrodiffusion

  • Water penetration into plant tissue.
  • Higher hydrodiffusion rate = lower hydrolysis and decomposition of constituents.
  • Coarse comminution and even charging are recommended.

Distilled Oil Artifacts

  • Insufficient distillation time results in oil fractionation.
  • High-boiling point constituents might not be carried with steam.
  • Volatile impurities (e.g., amines) can contaminate the product.
  • Sensitive constituents are affected by boiling water.

High Temperatures and Oil Purification

  • Esters hydrolyze.
  • Tertiary alcohols dehydrate to hydrocarbons.
  • Unsaturated terpenes polymerize.
  • Removal of bad-smelling or colored impurities by:
    • Re-distillation in steam.
    • Dry distillation under reduced pressure.
  • Removal of water and moisture by filtration over anhydrous sodium sulfate.

Comparison of Distillation Methods

  • Notes on the differences in types of plant materials suitable, mode of charging, hydrodiffusion, steam pressure, temperature, rate of distillation, and commercial preparation advantages and disadvantages.

Scarification & Expression Methods

  • Mechanical procedures at room temperature.
  • Puncturing and squeezing plant material to release oil.
  • Used for heat-sensitive oils (citrus fruits, other Rutaceae).

A- Sponge Method

  • Squeeze removed peels (e.g., orange).
  • Fruits are washed, halved, and fleshy parts removed.
  • Peels are soaked in water, turned inside out, pressed between a convex projection and sponge in a vessel saturated with oil emulsion.

B- Ecuelle-à-piquer Method

  • Puncturing (scarifying) whole fruits (e.g., lemon).
  • Oil forms an emulsion from the outer peel zone.
  • The instrument is funnel-shaped with a tubular projection at the center.
  • The bowl has numerous pins to scarify glands and release oil.
  • The tubular part acts as a handle and receiver.

C- Expression of Rasping Process

  • Removes the peel outer layer with a grater.
  • Collects raspings in special bags for strong pressing.
  • Collected oil emulsion in large vessels.

3. Solvent Extraction Methods

  • Extracting volatile oil from plant material using a suitable solvent.
    • Volatile solvent extraction
      • Enfleurage method
    • Non-volatile solvent extraction
    • Supercritical fluid extraction
  • Used for delicate flower oils (e.g., jasmine, violet, tuberose, narcissus).
  • Oils from thermolabile constituents (decomposed by heat).
  • Non-volatile solvents like fats (lard, tallow).
  • Products: Enfleurage product, Triple extract, Absolute of Enfleurage, or Volatile oil, and Fixed oils.

"Enfleurage" Process (Cold and Hot)

  • Method of extracting delicate flower oils using fat.

Enfleurage Process Preparation of Jasmine Oil

  • Details about equipment (lots of glass plates), procedure (spreading fat mixture on plates, layering flowers, replacing flowers, repeating until fat saturated, removing last charge, scraping, collecting, filtering, and cooling).

Volatile Solvent Extraction

  • Preparation of "floral concrete" and "floral absolute".
  • Absolutes are richer in oxygenated constituents responsible for odor.
  • Absolutes used in much smaller concentrations than concretes.

Supercritical Fluid Extraction

  • Extraction by supercritical gas.

Methods of Volatile Oil Preparation Summary

  • Comparison table of process, application, advantages, and disadvantages of different preparation methods (distillation, scarification/expression, and extraction).

4. Preparation of Volatile Oils from Glycosidic Combinations

  • Plant material hydrolyzed to free volatile constituents from a parent glycoside using specific plant enzymes.
  • Distillation or extraction of the plant material follows.
  • Purification of the volatile oils.

Storage of Volatile Oils

  • Remove metallic impurities (catalysts for decomposition).
  • Dry over anhydrous sodium sulfate to remove moisture.
  • Store in dark-colored, completely filled, and tightly closed containers.
  • Keep away from light, low temperature (in CO2 or N2 atmosphere, if necessary).

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Phytochemistry I Lecture 2 PDF

Description

This quiz covers the methods of preparation for volatile oils in phytochemistry. Key techniques such as distillation, extraction, and enzymatic hydrolysis are discussed, along with the apparatus used in water distillation. Test your knowledge on these important concepts!

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