Science Laboratory Technology





Cymbopogon citratus is also known as lemon grass is a genus of about 55 species of grasses, native to worm temperature and tropical regions of the old word and oceania. It is fall povennial grass, common names include barbed wire grass, silky heads, citronella grass, fever grass or hierba luisa (Adsimon 2001) among many others.

Lemon grass is native to Indian. It is widely used as a herb in Asaia Cuisine. It has citrus flavor and can be dried and powdered or use fresh. Lemon grass is commonly used on teas, soups and carries it is also suitable for poultry, fish and sea food, it is often used as a tea in African and Latin American. Example of other countries include: Toyo, Mexico, Congo. Research also shows that Lemon grass oil has anti-fungal properties. They are also antispectics, hence are use in household disinfectants, and soaps. Besides oil production, citronella grass is also used for culinany purpose, in tea and also in flavoring. Lemon grass oil, used as a pesticide and preservative, it put on the ancient manuscripts found in Indian in oriental research institute mysove. The lemon grass oil also injects natural fluidity into the brittle palm leaves and the hydrophobic nature of the oil keeps the manuscript dry so that the text is not lost to decay due to humidity. East Indian lemon grass (cymbopogon flexusus) also called cochin grass or malaba grass (malayalami (inchinpull), is native to Cambodia, Indian, strilanaka Burma and Thailand while the west Indian lemon grass (Cymbopogon Citratus) also known as serai in malay, is assumed to have its origin in Malaysia. Indonessian people used to call are seral to or search while both can be used interchangeably, but citrates is more suitable for cooking. In India, citrates is used both as a medical herb and in perfumes. Cymbopogon citratus is consumed as a tea for anxiety in Brazilian Folk medicine, but a study in human found no effect. The tea caused a recurrence of contact thermatitis in on the case lemon grass is also known as gavatichoha in the Marathi language (gavati grass, chaha-tea) and is used as an addition to tear and in preparation like “Kadha” which is a traditional herbal “soup” against cough, cold etc. it has medical properties and is used extensity in ancient Indian Ayhroetic medicines. It is supposed to help with relieving cough and nasal congestion. Anti cancer properties Weinstein, incumbent of the albent katz chair in cell differentiation and malignant disease from the department of microbiology and immunology at Ben Gurion University on Isreal, led a research team and found out that lemon grass (Cybopogon on citrates) caused apoptosis (programmed cell death) (Wristh 2002). Justification objectives of the study.



Occurrence and formation oil essential in plant. Essential oil are those adoroferous (diffusing – usually pleasure) oily products of plant which are distillable. Essential oil are produced on the protoplasm of plant cells. The oil being extracted which does not participate on the metabolism of the plant is very active in energy and also chemically active. Thus, some investigators maintain that many of these material are simply waste products of plants biosynthesis. Essential oil were viewed by (Mesnald 1998) as degradation products of chlorophyll, this chlorophyll is converted into essential oils which are volatile (evaporation rapidly). These oils are found to formed from glycosides (formal in the green plants). Once the glycosides encounter a medium at favoured condition, it decomposes to essential oil. The oils formed are stored in the form of moirodroplets in the glands of the plants.


Lemon grass oil has a wild range of industrial application in areas like scap and detergent production cosmetics perfumes, pharmaccuticals, beverage and flavouring industries, others are deodorants, toiles preparations, food flavouring beverage examples of tobacco and some may be used as antiseptics, stimulants or ingredient in medical products. Some are used as laboratory reagent or in paints, some are component in inks and insecticides.


The major principal constituent of essential oil are the terpenes, Benzenoids, Alophatic compounds and reterocylic compounds. The oil from lemon grass contains mainly citral, while that of mustard contains organic isothiocyanates, garlic and onions contain sulphide indole and anthranilates which at times occurs in small amounts.


The different physical method available for the extraction of essential oil from their natural sources include the following expression, enfleurage, maceration, solevent extraction and steam distillation.


This method is mainly used for citrus, this process is done by hand or machine. The essential oil of citrus is contained in numerous oval shaped sacs distributed throughout the peel (skin of certain fruits and vegetables). This process involves mechanical rupturing of the sac to liberate oil which is collected as a slurry with all water and debris (scattered broken pieces). The oil is separated by process of decantation centrifugation a filtration.


Essential oil of delicate flower petals still are prepared by enfleurage which is the absorption of oil on purified fat on special pressing machine equipments. The process is repeated many times until the fat is saturated. The fat is removed and extracted with alcohol and recycled.


This is an alternative form of enfleurage instead of long enfleurage process, the flower petal in hot fat 40 – 60c for a shorter period of time, in an attempt step.


This is the extraction of oil from plant using solvent. The solvent to be used depend on the plant to be treated. The solvent enters the cell of the vegetable and not only dissolved the essential oil but also dissolved waxes and colours. After extraction, remove the solvent by distillation a semi floral concrete are left behind. This concretes extracted with high-proof alcohol, after which this second extraction is cooled to precipitate the waxes and then filtered. This method is costly due to the solvent of high grade used.


This method of isolation of essential oil is the most common and is used when the stability of the oil is very high. Steam distillation may be used under reduced pressure when the stability of the oil is low.

There are three different method of steam distillation;

  1. Water Distillation: In this method, the vessel containing water which is in direct. Contact with the chopped plant material is recovered through a water cooled condenser. Water distillation is a mild but slow process which yield a superior product from cloves and nutmeg.
  2. Wet Steam Distillation: This method involves the introduction of steam which is produced on a separated vessel (steam can) into another vessel (distillation chamber) which contains the raw materials and water acts either directly or through a spiral covered by water. The oil is collected from the condenser, which is water cooler, this is the most common method used.
  3. Dry Distillation: Here the vessel containing the plant material is heated to prevent only water condensation from the incoming steam, thus achieving a dry steam distillation and the gives rise to grading in order to prevent burning of plant materials. The forest and second losses owing to hydro solubility of certain component of the oil.




This is used to know or weight, the weight of the extracted oil, thible, the bottle or the raw material (lemon grass).


This is used to hold or stand the round bottom flask.


This is the cool the extractor (sourcelect extraction apparatus).


This is the raw material which the solvent (hexane) act on in order to produce the essential.


This is where the water passes through into the condenser tube.


This is acts as a source of heat supply to the experiment.


The retort stand was used to stand the sourcelect extraction apparatus, two boilers was immersed in a water bath which acts as a sources of heat supply to the round bottom flask which contains the solvents (hexane). The vapour or the steam from the solvent now acts on the thible which contains the dried and chopped raw material (lemon grass) sold with cotton wool in the extractor. The delivery tube was connected from the bucket to the condenser tube where it cools the sourcelect extraction apparatus and goes off from the other delivery tube to the other bucket. As the level of water decreases it was refilled.

Back as the process continues. As the water from the water bath gets hot the solvent (hexane) in the round bottom flask started boiling after ten minutes thereby releasing hot stream which helps to release the aromoso molecules. The molecules of these volatile oils than escape from the raw materials and evanorate into the steam. The steam is produced at greater pressure than the atmosphere and therefore boils as above loodegrees Celsius which facilitate the removal of the essential oil from the raw material at a faster rate and in so doing prevents damage to the oils. Some oils like lavender is heat sensitive (thermolabile) and with this extraction method, the oil is not damage and ingredients like linalyl acetate will not decompose to ionalool and acetic acid. The vapour or steam from the solvent (hexane) now act on the thible containing the raw material (lemon grass) thereby extracting oil from it which passes from the extractor to the round bottom flask. The whole experimental process lasted for 2 hours for complete distillation.


This method can be defined as the isolation of essential oil from the solvent used. Therefore steam distillation method was used in isolating or separating the solvent (hexane) from the oil in order to know the quantity of the essential oil extracted. The essential oil produced was collected and weighed; the weight of the essential oil is 11.38g. The weight of the thible be form extraction 4.0g weight 0 the thible after extraction 9.0g the weight of the bottle without oil 68.28g weight of the bottle with extracted oil produced 79.66g therefore, 7.66g – 68.28g = 11.38g (weight of oil produced).




The oil produced from the raw material (Lemon grass) was dark in colour when freshly distilled.But its normal colour is greenish yellow which has a whole application in durgs,beverages etc. the weight of the essential oil extracted is 11.38g.


When a few drops of lemon grass oil is dropped in 1cm3 of acetone, there is a formation of a cloudy solution which indicates that it is insoluable. It is also insoluble in ethanol. But it may be soluble in some organic solvents.

Specific gravity is the ratio of mass of a substance to the mass of equal volume bottle and a chemical balance, and also calculated.

Thus: Mass of oil

Mass of equal volume of H2O

Is present on standing

Refractive index is define as the ratio of the since of angle of incidence to the sine of angle of refraction. This is done by a refractometry method analysis from the index of refraction =

sin i

Sin r


Generally the colour of essential act are greenish when freshly distilled, but the colour may change from red to blue when foreign matter is present on standing the gradually yellow.

The table below sow result which were obtained from the analysis of the result.

TABLE 1: Percentage yield and colour of the oil.

Sample Percentage Colour
Essential oil Extracted 11.38g Greenish yellow

TABLE 2: Some physical constants

Physical parameter Quantity
Specific gravity 1.332
Refractive index 1.332
Solvbility of acetone Insoluble
Solubility of etanol Insoluble


Chemical test and analysis are carried out the extracted product. These serve to determine the quantity of the oil and they are the characteristics test of the extract oil. These may also be employed in the synthesis of other important compounds. The reactions include:

  1. Reduction Reaction: Citral upon reduction wit sodium amalgam yields geranoil an important component of rose perfumes.
  2. Oxidation Reaction: Oxidation of citral wit alkaline potassium permoganate, followed by chronic acid gives a cetone oxalic laevolic acids.
  3. Condensation: Reaction citral when condensed with acetone yields an important intermediate pseudo 4ionone to B-ionone.
  4. Reaction with potassium hydrogen sulphate on heating wit major component of the oil forms B-cynen (ii) (semmiller 1891)


For organoleptic testing, the end of a strip of odourless blotting, paper (about 15cm long and 0.6cm wide) was dipped into the oil exactly the same amount of the standard oil was placed on a second blotter. Two odour evolved were garfully studied and noted at intervals. The move volatile adulterants, as well as solvent by notes of extracted oils. Often are discovered when the oil was freshly applied to the blotters. When blotters have dried considerably, it is often possible to defect less volatile adulterants, as well burnt by notes resulting from faulty distillation. Highly trained experts are then capable of differentiating various constituents. This serve as confirmatory test for the extracted oil.



The oil extracted from the lemon grass was certified to retain the same properties with standard oil. There is also nolegal constraints on the use of lemon grass and also fema grass (2624) and council of Europe listed extraction of the oil was effectively achieved by steam distillation method. This was preferred to every type of extraction method because it yield a good amount of oil and a high quality when compared with other methods. Te percentage yields and qualities of the oil from lemon grass can be applied in many cosmetics and pharmaceuticals industries as a substitute for these oils imported at exorbitant prices from oversea. It also serve to reduce the costs incurred in the production of most finished products like cosmetics, perfumes, beverages, drugs etc.

Therefore, the aim and objectives of this project work has been achieved the research work, which has been successfully completed, encountered some problems and difficulties on the course of it. These include, the scare availability of the lemon grass at this part of the country. In the midst of the above and other difficulties not withstanding, the purpose and aim of the research work is feasibly arrived at the end.

Its was observed that when the extracted oil was stored in a transparent bottle look dark on colour from far view but greenish yellow at closer look, with is its normal colour.


On the light of the project work and the above case 1 intend to submit the following recommendation and enhancing the efficiency of the extraction of oiland procurement of these oils overseas.

That effort should also be made by government agencies and agricultural researcher toward finding and bleeding the improved strains of the grass which can with stand adverse climatic conditions especially during dry season. The government should also provide some of the sophisticated and computerized equipment to get the oil maximum yield and of highest quantity.


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