The presentation gives the basic information regarding the extraction in food matrix. It includes basics of extraction, principles of extraction and the theory behind the solvent extraction. It also involves terms and terminologies involved in the extraction process, Factors affecting extraction efficiency and Types of Extractors. Mixer-Settlers for extraction, Spray extraction towers, Plate towers contactors, etc.
2. Extraction may be defined as the removal of soluble constituents from a solid,
liquid or semi-solid with means of suitable solvent.
It may be defined as the treatment of the plant or animal tissues with
appropriate solvent, which would dissolve the medicinally active constituents.
Extraction
3. Extraction is the method of removal of a soluble fraction in the form of a solution
from an insoluble matrix with the help of a suitable solvent.
oThe soluble components may be present either as
a solid or liquid
oInsoluble matrix may be
in powder form, openly porous or non porous or cellular with selective
permeable cell walls as in case of vegetable and animal tissues.
Extraction
Extraction
Solid – Liquid
Extraction
Liquid – Liquid
Extraction
Leaching
4. Solvent extraction, or liquid–liquid extraction, is the separation of impurities (solutes)
from a liquid solution by contacting it with another immiscible liquid (solvent) in
which the impurities have a high affinity.
The high affinity driving the separation can be either
◦ Physical solubility differences
◦ Chemical reaction.
The solvent may be a
◦ Single component liquid
◦ Mixture
Liquid-liquid extraction
6. Basic steps in extraction
Typical liquid-liquid extraction operations utilize
the differences in the solubilities of the
components of a liquid mixture.
The basic steps involved include:
1. Contacting the feed with the extraction solvent.
2. Separation of the resulting phases
3. Removal/recovery of solvent from each phase.
7. Extraction is process of transferring substance of a water phase in organic
Menstrum is reagent which with investigated substance forms compound which then is
extracted
Extract - is a substance made by extracting a part of a raw material, often by using a
solvent such as ethanol or water. Extracts may be sold as tinctures or in powder form
Re-extraction is process of transferring substance of organic phase in water
Raffinate / Marc is a liquid from which impurities have been removed by solvent
extraction
Terminologies in Extraction
8. Polar : water (Di-electric constant: 80), Methanol : (33), Acetone : (21)
Non-polar : Chloroform (4.81), Hexane (1.88), Benzene(2.3) , toluene (2.38) , diethyl-
ether (4.3), Solvents with a dielectric constant of less than 15 are generally considered
to be non-polar.
Should not mix up with water.
Should be selective.
Should have the big capacity in
relation to extractive.
Conditions of a choice of solvent
The density of extragent should be
difference from water density.
Should have the minimum viscosity.
Should be inexpensive.
Cannot be explosive.
9. Single component liquid
oHexane
oEther
oToluene
oWater
oDichloromethane
oChloroform
Mixture
oWater and Ether
oEther and Methylene chloride
oAcetone and Ether
oWater and Acetone
oWater and Methylene chloride
oEther and Dichloromethane
Common used solvents
10. For a given compound, solubility difference between solvents is quantified as
Distribution Coefficient or partitioning coefficient.
Distribution Ratio: measure of how well a species is extracted.
It is the ratio, K of the solubility of solute dissolved in the organic layer to the
solubility of material dissolved in the aqueous layer.
K is independent of the actual amounts of the two solvents mixed.
Extraction efficiency
11. The constant K, is essentially the ratio of the concentrations of the solute in the two
different solvents once the system reaches equilibrium.
At equilibrium the molecules naturally distribute themselves in the solvent where they
are more soluble.
Inorganic and water soluble materials will stay in the water layer and more organic
molecules will remain in the organic layer.
K= distribution coefficient =
𝑆𝑜𝑙𝑢𝑏𝑖𝑙𝑖𝑡𝑦 𝑖𝑛 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 (𝑔/100𝑚𝐿)
𝑆𝑜𝑙𝑢𝑏𝑖𝑙𝑖𝑡𝑦 𝑖𝑛 𝑤𝑎𝑡𝑒𝑟 (𝑔/100𝑚𝐿)
Extraction efficiency
12. Extraction efficiency
Unless K is very large, not all of a solute
will reside in the organic layer in a single
extraction.
Usually more than one extractions of the
aqueous layer with an organic solvent are
carried out in sequence in order to remove as
much of the desired product from the
aqueous layer as possible.
13. Temperature
Suitable size reduction
Penetration of drug by the solvent
Solution of the soluble matter within the cells
Escape of dissolved material through the cell walls and through the boundary
layer surrounding the particles
Separation of the solution and exhausted drug
Factors affecting extraction efficiency
14. Separation of elements
Concentrating impurities
Clearings of the basic component from impurities
Definition of the basic component from impurities
Identification and quantitative definition of chemical agent or substances-
markers
Increase of sensitivity and selectivity of reactions
Studying of formation constant of complexes
Studying of substance condition in a solution (a charge, polymerisation degree)
Applications of Extraction
15. Column
Contactors
Mixer Settlers
Centrifugal
Used primarily in the metals
industry due to:
- Large flows
- Intense mixing
- Long Residence time
- Corrosive fluids
- History
Used primarily in the
pharmaceutical industry due to:
- Large flows
- Intense mixing
- Long Residence time
- Corrosive fluids
- History
Static Agitated
Spray Packed Tray Pulsed Rotary
Reciprocating
Rarely used Used in:
- Refining
- Petrochemicals
Used in:
- Refining
- Petrochemicals
Used in:
- Nuclear
- Inorganics
- Chemicals
Used in:
- Chemicals
- Petrochemicals
- Refining
- Pharmaceutical
Types of Extractors
21. Generally the desired liquid is dissolved in the solvent and then get extracted.
To improve the efficiency, pretreatments are given to the mixture.
The following pretreatments are generally applied to improve the efficiency.
Microwave pretreatment
Ultrasound pretreatment
High Pressure Processing
Pulse Electric Field Processing
Cold plasma pretreatment
Recent development in solvent extraction
A mechanical mixer is often used to provide intimate contact between the two liquid phases.
Used in extraction of uranium salts or copper salts from aqueous solutions.