Phytochemistry I Lecture 2: Preparation Methods
40 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

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</p> Signup and view all the answers

    What is the main disadvantage of water distillation?

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

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

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

    Which distillation method allows for modified steam pressure?

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

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

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

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

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

    Which method is most suitable for oils rich in esters?

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

    How is the removal of water and moisture typically accomplished?

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

    What is a potential issue with hydrodiffusion in distillation?

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

    Which distillation method typically provides the highest rate of distillation?

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

    What is a notable advantage of water and steam distillation?

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

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

    <p>Saturated steam distillation</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</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.</p> Signup and view all the answers

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

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

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

    <p>Condenser</p> Signup and view all the answers

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

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

    Which solvent type is primarily used in the enfleurage method?

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

    What is a key characteristic of oils extracted using enfleurage?

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

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

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

    What is the final product obtained after the enfleurage process?

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

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

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

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

    <p>Defleurage</p> Signup and view all the answers

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

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

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

    <p>Distillation</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</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</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</p> Signup and view all the answers

    What is a major application for supercritical fluid extraction?

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

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

    <p>Hydrolysis</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</p> Signup and view all the answers

    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).

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    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!

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser