In the perfume industry, most modern essential oil production is accomplished by extraction, using volatile solvents such as petroleum ether and hexane. This feature is of considerable importance to the perfume industry; however, the established distillation method is of lower cost than the extraction process.
Destructive distillation means distilling volatile oil in the absence of air. When wood or resin of members of the Pinaceae or Cupressaceae is heated without air, decomposition takes place and a number of volatile compounds are driven off.
The residual mass is charcoal. Hydrodistillation In order to isolate essential oils by hydrodistillation, the aromatic plant material is packed in a still and a sufficient quantity of water is added and brought to a boil; alternatively, live steam is injected into the plant charge. Due to the influence of hot water and steam, the essential oil is freed from the oil glands in the plant tissue. The vapor mixture of water and oil is condensed by indirect cooling with water.
From the condenser, distillate flows into a separator, where oil separates automatically from the distillate water. Mechanism of Distillation Hydrodistillation of plant material involves the following main physicochemical processes: i Hydrodiffusion ii Hydrolysis iii Decomposition by heat Hydrodiffusion Diffusion of essential oils and hot water through plant membranes is known as hydrodiffusion.
In steam distillation, the steam does not actually penetrate the dry cell membranes. Therefore, dry plant material can be exhausted with dry steam only when all the volatile oil has been freed from the oil-bearing cells by first thorough comminution of the plant material. But, when the plant material is soaked with water, exchange of vapors within the tissue is based on their permeability while in swollen condition.
Membranes of plant cells are almost impermeable to volatile oils. Therefore, in the actual process, at the temperature of boiling water, a part of volatile oil dissolves in the water present within the glands, and this oil-water solution permeates, by osmosis, the swollen membranes and finally reaches the outer surface, where the oil is vaporized by passing steam.
Another aspect of hydrodiffusion is that the speed of oil vaporization is not influenced by the volatility of the oil components, but by their degree of solubility in water. Therefore, the high-boiling but more water-soluble constituents of oil in plant tissue distill before the low- boiling but less water-soluble constituents. Since hydrodiffusion rates are slow, distillation of uncomminuted material takes longer time than comminuted material.
Hydrolysis Hydrolysis in the present context is defined as a chemical reaction between water and certain constituents of essential oils. Esters are constituents of essential oils and, in the presence of water, especially at high temperatures, they tend to react with water to form acids and alcohols.
Therefore, if the amount of water is large, the amounts of alcohol and acid will also be large, resulting in a decreased yield of essential oil. Furthermore, since this is a time-dependent reaction, the extent to which hydrolysis proceeds depends on the time of contact between oil and water. This is one of the disadvantages of water distillation. Effect of Heat Almost all constituents of essential oils are unstable at high temperature. To obtain the best quality oil, distillation must be done at low temperatures.
The temperature in steam distillation is determined entirely by the operating pressure, whereas in water distillation and in water and steam distillation the operating pressure is usually atmospheric. All the previously described three effects, i. The rate of diffusion usually increases with temperatures as does the solubility of essential oils in water. The same is true for the rate and extent of hydrolysis.
Three Types of Hydrodistillation Three are three types of hydrodistillation for isolating essential oils from plant materials: 1. Water distillation 2. Water and steam distillation 3. Direct steam distillation Water Distillation In this method, the material is completely immersed in water, which is boiled by applying heat by direct fire, steam jacket, closed steam jacket, closed steam coil or open steam coil.
The main characteristic of this process is that there is direct contact between boiling water and plant material. When the still is heated by direct fire, adequate precautions are necessary to prevent the charge from overheating.
When a steam jacket or closed steam coil is used, there is less danger of overheating; with open steam coils this danger is avoided. But with open steam, care must be taken to prevent accumulation of condensed water within the still. Therefore, the still should be well insulated.
The plant material in the still must be agitated as the water boils, otherwise agglomerations of dense material will settle on the bottom and become thermally degraded.
Certain plant materials like cinnamon bark, which are rich in mucilage, must be powdered so that the charge can readily disperse in the water; as the temperature of the water increases, the mucilage will be leached from the ground cinnamon. This greatly increases the viscosity of the water-charge mixture, thereby allowing it to char.
Consequently, before any field distillation is done, a small-scale water distillation in glassware should be performed to observe whether any changes take place during the distillation process.
From this laboratory trial, the yield of oil from a known weight of the plant material can be determined. The laboratory apparatus recommended for trial distillations is the Clevenger system. During water distillation, all parts of the plant charge must be kept in motion by boiling water; this is possible when the distillation material is charged loosely and remains loose in the boiling water. For this reason only, water distillation possesses one distinct advantage, i. Other practical advantages of water distillation are that the stills are inexpensive, easy to construct and suitable for field operation.
These are still widely used with portable equipment in many countries. The main disadvantage of water distillation is that complete extraction is not possible. Besides, certain esters are partly hydrolyzed and sensitive substances like aldehydes tend to polymerize. Water distillation requires a greater number of stills, more space and more fuel.
It demands considerable experience and familiarity with the method. The high-boiling and somewhat water-soluble oil constituents cannot be completely vaporized or they require large quantities of steam.
Thus, the process becomes uneconomical. For these reasons, water distillation is used only in cases in which the plant material by its very nature cannot be processed by water and steam distillation or by direct steam distillation. Traditional Method of Producing Attar Using Hydrodistillation Floral attars are defined as the distillates obtained by hydrodistillation of flowers such as saffron, marigold, rose, jasmine, pandanus in sandal wood oil or other base materials like paraffin.
Attar manufacturing takes place in remote places because the flowers must be processed quickly after collection. The apparatus and equipment used to manufacture attar are light, flexible, easy to repair, and have a fair degree of efficiency. Water and Steam Distillation In water and steam distillation, the steam can be generated either in a satellite boiler or within the still, although separated from the plant material. Like water distillation, water and steam distillation is widely used in rural areas.
Moreover, it does not require a great deal more capital expenditure than water distillation. Also, the equipment used is generally similar to that used in water distillation, but the plant material is supported above the boiling water on a perforated grid. In fact, it is common that persons performing water distillation eventually progress to water and steam distillation. It follows that once rural distillers have produced a few batches of oil by water distillation, they realize that the quality of oil is not very good because of its still notes subdued aroma.
As a result, some modifications are made. Using the same still, a perforated grid or plate is fashioned so that the plant material is raised above the water. The application of essential oils as antimicrobial, anticancer, anti-inflammatory and anti-viral agents is due to their effective and efficient properties, inter alia.
Method: Several advanced supercritical fluid extraction, subcritical extraction liquid, solvent-free microwave extraction and conventional hydrodistillation, steam distillation, hydrodiffusion, solvent extraction methods have been discussed for the extraction of essential oils.
Advanced methods are considered as the most promising extraction techniques due to less extraction time, low energy consumption, low solvent used and less carbon dioxide emission.
For water analysis, It has the target of allowing students to analyze different physico-chemical parameters such as pH, alkalinity, conductivity, total dissolved solids, Hardness, color, turbidity, etc and determine the concentration of different ions in given samples of water. The second session was the extraction of essential oils. We know that Essential oils are highly concentrated, volatile substances extracted from flowers, leaves, stems, roots, seeds, barks, or fruit rinds of plants and they are used for their characteristic smell and their therapeutic or odoriferous properties, in a wide selection of products such as foods, medicines, and cosmetics.
The world production and consumption of essential oils are increasing very fast. So, during internship, we were interested in knowing the amount of essential oil that are produced by different plant species and compare them in overall yield and quality of essential oil they produce. The other covered activity is the extraction of oil and fats from natural products such as soybeans and groundnuts. Oils and fats are lipids extracted from vegetables, nuts, seeds, milk, avocadoes, etc.
These Fats and oils are extensively used as food and also in cosmetics, pharmaceuticals and other industries. They constitute an important resource in the food and cosmetic fields. In the internship, we found out the amount of oil in two lipid- containing seeds which are soybean and groundnut. The extraction of oil and fat was done using soxhlet extractor apparatus.
A Soxhlet extractor is a piece of laboratory apparatus invented in by Franz von Soxhlet and it was originally designed for the extraction of a lipid from solid materials as ours soybean and groundnut. But due to the increased human population, industrialization, use of fertilizers in the agriculture and man-made activity it is highly polluted with different harmful contaminants.
This contamination causes water born-diseases which have led to the death of millions of people. Adefemi and Awokunmi, It is very essential and important to test the water before it is used for drinking, domestic, agricultural or industrial purpose. Water must be tested with different physic-chemical parameters and the parameters to test in water are solely depend upon for what purpose we going to use that water and what extent we need its quality and purity. Lipids fats and oils are a group of substances that, in general, are soluble in organic solvents but are relatively insoluble in water.
Lipids Fats and oils have became an integral part of human diet. It is also projected to continue growing. The increase in oil production which began with the application of solvent extraction method, made the access to these commodities easier.
Because of commercial regulations, it is important for food producers and consumers to be able to report fat content in a serving size of a food item. The Soxhlet procedure allows for the calculation of total lipids fat and oils content in seeds like soybeans and groundnuts or other natural products.
In many of its published methods, the U. Environmental Protection Agency requires Soxhlet extraction of components from a variety of sample matrices including foods and soils. The other purpose is to improve the personal ability for using laboratory materials and apparatus. It also experiences us about working in team and being familiar with working environment. Introduction Seed oils, Nuts oils and oils of fruits and vegetables are receiving growing interest due to their high concentration of bioactive lipid components, such as polyunsaturated fatty acids and phytosterols, which have shown various health benefits.
Fats and oils, and their several lipid components are extensively used in the food and also in cosmetics, pharmaceuticals, oleochemicals and other industries. Supercritical fluid extraction allows obtaining extracts free of toxic residues that can be directly used, without any further treatment, and with excellent features and ultra pure composition of final product.
Objectives The objective of oil and fats extraction is to determine lipid contents of various oil-seeds by weight in a sample. This session helped me to calculate the yield of oils from two different seed species and compared them in oil production. It also helped in gaining some skills about operation of a Soxhlet extractor. The later method was used during this session. Mechanical methods Mechanical extraction of the oil is accomplished by exerting sufficient force on confined seed.
Chemical methods Those methods are applicable to almost of fats-containing products. They consist of using the chemical solvents to remove oils from seeds. Chemical method is commonly used at small scale and for research purposes. Soxhlet method It is a method of extraction in which the soxhlet extractor is used. A Soxhlet extractor is a piece of laboratory apparatus invented in by Franz von Soxhlet. It was originally designed for the extraction of a lipid from a solid material.
However, a Soxhlet extractor is not limited to the extraction of lipids. Typically, a Soxhlet extraction is only required where the desired compound has a limited solubility in a solvent, and the impurity is insoluble in that solvent. If the desired compound has a significant solubility in a solvent then a simple filtration can be used to separate the compound from them insoluble substance.
Figure 1soxhlet extractor connected with condenser and round-bottomed flask. We weighed 0. Note: It is better to use the powder of sample in order to facilitate its dissolution in solvent. From the obtained powder, we weighed in About ml of petroleum Ether is poured into ml round-bottomed flask with boiling chips. The solvent is boiled ; the vapors rise to the condenser where they condense and drip down through the sample back into the boiling solvent below. The extraction process is continuous and was completed between3 and 4 hours.
In the condenser, the vapors are condensed and drip into the sample-containing thimble. When the level of liquid reaches the same level as the top of the siphon, the liquid containing the extracted material is siphoned back into the boiler.
Figure 3 : Rotary evaporator Rotavapor Figure 4: Rotary evaporator in use Once the extraction is finished, the solvent is removed from the extracted oil by distillation using a Rotavapor, also called Rotary evaporator, Which is the instrument used in distillation to separate solvents and oils at low pressure. Note: At low pressure the boiling point of a compound becomes slightly low, this is important for some organic compounds that can be destroyed or volatilized at high pressure high temperature.
At the end of distillation , we got separately both , oils and solvents. Solvent should also be used again and again since it's regained at the end of distillation. From sample of Groundnut peanut. Mass of Sample Groundnut powder : From sample of Soybeans.
Mass of Sample Soybean powder : This means that, the groundnut is a higher lipid- containing species than soybeans. Introduction Essential oils are highly concentrated, volatile substances extracted from flowers, leaves, stems, roots, seeds, barks, resins, or fruit rinds of plants.
Not all plants produce essential oils. These oils are present in natural products at small amount because the amount of essential oils found in these plants can be anywhere from 0. That's why tons of plant material are required for just a few hundred pounds of oil.
Extraction of essential oils is one of the most time- and effort- consuming processes. There are a wide number of ways to extract the Essential oil but the quality never remains the same, it means that the way in which oils are extracted from plants is important because some processes use solvents that can destroy the therapeutic properties. So, based on their uses, the objective of extracting essential oils from different plant species is to know the amount and yield of essential oils produced, so that we make a comparison of plant species in production of essential oils.
Chemical Constituents of Essential Oils The chemical composition of both vegetable oils and essential oils is complex and the exact chemical composition of each oil depends on the plant species from which it was extracted from. Pure essential oils are mixtures of more than components, normally mixtures of terpenes or phenylpropanic derivatives, in which the chemical and structural differences between compounds are minimal. They can be essentially classified into two groups: Volatile fraction, such as aliphatic aldehydes, alcohols, and esters.
Nonvolatile residues, such as fatty acids, sterols, carotenoids, waxes, and flavonoids. Hydrocarbons: Essential Oils consist of Chemical Compounds that have hydrogen and carbon as their building blocks. Ketones Essential oils containing ketones are beneficial for promoting wound healing and encouraging the formation of scar tissue. Ketones are usually not always very toxic.
The most toxic ketone is Thujone found in mugwort and wormwood oils. Other toxic ketones found in essential oils are pulegone in pennyroyal, and pinocamphone in hyssops. But there are Some non-toxic ketones like jasmone in jasmine oil, fenchone in fennel oil, and menthone in peppermint oil.
Alcohols Alcohols exist naturally, either as a free compound, or combined with a terpenes or ester. They improve the quality of essential oils for their anti-septic, anti-viral, bactericidal and germicidal Properties. Here are some alcohols found in typical essential oils: linalool found in ylang-ylang and lavender, Geraniol in geranium and rose. Terpenes are anti- inflammatory, antiseptic, antiviral, and bactericidal.
Terpenes can be further categorized in monoterpenes, sesquiterpenes and diterpenes. Limonene Menthol 5. Aldehydes Medicinally, essential oils containing aldehydes are effective in treating Candida and other fungal infections because of their anti-fungal, anti-inflammatory, and anti-viral Properties. Example of Citral in lemon and citrus eucalyptus. Plant acids act as components or buffer systems to control acidity.
Example of Cinnamic and benzoic acid in benzoin. Ester Essential oils containing esters are used for their soothing, balancing effects. Because of the presence of alcohol, they are effective antimicrobial agents. Medicinally, esters are characterized as antifungal and sedative, with a balancing action on the nervous system. Some methods that are used for extractions of essential oils are given below: a. Hydro distillation This method is often used in primitive countries.
The risk is that the still can run dry, or be overheated, burning the aromatics and resulting in an Essential Oil with a burnt smell. Hydro distillation seems to work best for powders spice powders, ground wood, etc. This method is cheaper and was preferred during our internship.
Solvent Extraction An hydrocarbon solvent is added to the plant material to help dissolve the essential oil. From the concentrate, pure alcohol is used to extract the oil. When the alcohol evaporates, the oil is left behind. Steam Distillation The most essential oils are commonly extracted from the plants using this technique.
One type of distillation places the plants or flowers on a screen. Steam is passed through the area and becomes "charged" with the essence. The steam then passes through an area where it cools and condenses. This mixture of water and essential oil is separated and bottled. Cold Pressing This method involves the simple pressing of the rind at about degrees F to extract the oil.
The rinds are separated from the fruit, are ground or chopped and are then pressed. The result is a watery mixture of essential oil and liquid which will separate given time. It is important to note that oils extracted using this method have a relatively short shelf life, so make or purchase only what you will be using within the next six months.
Cold pressing is used to extract the essential oils from citrus rinds such as orange, lemon, grapefruit and bergamot.
0コメント