The Bleaching of Palm Oil Using Activated Charcoal
Chapter One
OBJECTIVE OF THE STUDY
The objective/aim of this research project is to verify the effectiveness of ‘Activated charcoal’ in the bleaching of palm oil. It will also expose the improvement in the use of local raw material (charcoal) in a chemical process (bleaching), in lien of the imported fuller’s Earth or other adsorbents which more expensive.
CHAPTER TWO
LITERATURE REVIEW
Palm oil is produced by the processing of the fruit of the palm tree (Elaesis Guineassis). The sources (palm tree) is cultivated mainly as plantations in Malaysia, Indonesia, Nigeria and Congo, in various method. An other product obtained in the processing of palm oil is the palm kernel, from which the palm kernel oil and cake could be processed.
Palm oil is composed of two compounds:
Saturated and unsaturated glycosides of fatty acids, both having a principal component of palmitic acid (96) and oleic acid. The fatty acid glycerin composition of the oil varies according to country of origin, the species of tree; and method of processing.
According to Onwuna (1983) the physical and chemical characteristics of Nigerian palm oil shows that it is made up of specific gravity 0.921 – 0.925) Refractive Index (1.453 to 1.456) and melts at temperatures of between 270c. Its chemical properties are saporifivation value (195 – 205) iodine value (44 to 54) Oil content (30 – 40%) etc. Other composition by percentage Include:
Palmic acid 41.2%
Steasic acid 4.3%
Mynstic acid 2.3%
Carotene 2%
Lipids, phosphatides and Gum, for the saturated, while the unsaturated in made up of oleic acid (42.5%) and linaliec (9.6%).
CHEMICAL COMPOSITIONS OF PALM OIL
As stated above, palm oil consists of carotene, fatty acids, phospolipids (phosphotides) and Gums.
CAROTENES
This forms the minor constituent of palm oil which give it a characteristic deep orange colour and when it is conspicuous the oil is tuned “red palm oil”. It is also a source of vitamin A. the carotenoid pigment is made up of the groups, the &, B and Y, together with lycopene and lutein (xanthophylls) with the oil being uchec in carotene, which has twice the vitamin A activity of either & – carotene f the Y – carotene.
It could be pointed out that the deep orange pigment is caused by the extended corrugation of the carotenoid materials; and as a hydrocanton with long chain of double bond, its molecular fomular is (40 H56.
Vitamin A is produced when the carotene is molecular is split into two halves in an addition of water to both parts. The Beta (B) group of the carotene has identical equal halves, unlike is the other carotene types where only are halve constitute the necessary vitamin A formation.
CHAPTER THREE
EXPERIMENTAL PROCEDURE
MATERIALS
The materials used for this experiment are adsorbent (Bone charcoal)
Palm oil
Acid (H2 504)
MATERIAL TREATMENT
TREATMENT OF THE CHARCOAL PRIOR TO ACTIVATION
For the purpose of the activation, an already carbonized bone charcoal was used. Lumps of dried bone charcoal were crumbed into small particles in order to expose the surface area for reaction. The crushed bone charcoal was then carbonized at a temperature of 2500C for about 3½ hrs. it was allowed to cool-off and then saved to get a mesh size of 200 Um.
CHARCOAL ACTIVATION USING SULPHURIC ACID (H25S04)
To optimize the adsorptive strength of the charcoal, it was subjected to an acid activation using a concentrated sulphuric acid (H2 S04).
A sample of the sieved carbonized charcoal weighing 600g was poured inside a reactor (pot) and the concentrated H2 S04 acid, by weight 300g was poured into the same reactor with charcoal, that is sample (charcoal) to acid ratio is 2:1 by weight.
CHAPTER FOUR
EXPERIMENTAL RESULT
To determine the amount or degree in colour reduction of the palm oil, the absorbance of both the original palm oil and the bleaching oils were measured at a selected wavelength using a spectrophotometer. This result was converted and expressed percentage in colour reduction (% C.R)
The palm oil has the following properties specific gravity: 0.908g
Weight of the oil sample: 90.8g
Absorbance at 480 um (wavelength) : 1.65.
CHAPTER FIVE
DISCUSSION
The purpose of this experiment is to determine the bleaching effect of activated charcoal. It is worthy of note that the methods of colour removal or bleaching vary to some extent dependent on the type of pigment present and the fat being treated. In addition to this adsorption process depends on the affinity of the adsorbent for the colouring matter, whether it is dissolved or colloidally dispensed in the oil. Adsorption bleaching which was used in this study was based on the fact that charcoal is a kind of decolourising active carbon, as made from bone and also the adsorption process has an advantage of utilizing heat effect on the bleaching sample (oil) while the activated charcoal forms a solution with the oil.
It would be however recalled that the purpose of activating the charcoal is to enlarge the pores already existing in the charcoal and also develop new pores, by the removal of volatile material and / or by gasification of the basic substance so that adsorption becomes more permissible.
CHAPTER SIX
CONCLUSION
From researches and this project experiment sofar, it has been found that the use of ‘charcoal’ as an adsorbent for bleaching process is a good substitute for other kinds of adsorbents like, bleaching earths (clays, fuller’ Earth, Alumna, etc) and bleaching solvents.
A critical examination of the results (bleached oils) obtained with the acid treated charcoal and the ordinary acturated sample showed that efficiency in colour reduction is high with the acid (H2 So4) activated charcoal. Hence, the properties of the Bleached oil stands better than those of the original palm oil.
CHAPTER SEVEN
RECOMMENDATION
Bleaching of crude palm oil for various usages is recommended since the bleaching reduces the undeniable colour of the oil and criminates these organic compounds which can affect the flavour, taste and quality of produced foods; studies have shown that there is no fixed standards for bleaching oils, rather processors bleaches to their desire, depending on the use of the oil and other factors that right limit the process.
The use of charcoal for bleaching oil and other production is highly recommended, because not only that the materials are locally sourced at a cheap rate, “charcoal” on its own has been examined to be the most safe’ material on earth. It has no effect in living things, hence its wider application, in other areas.
But then, the acid effect of activated charcoal contradicts the safe nature of the original charcoal. Therefore, it is recommended that the activated charcoal be desulphurised after the activation before using for bleaching, to curtail the obnoxious effects of the sulphuric acid to the finished product (bleached oil)
For optimization of the bleaching, it is recommended that the temperature of the activation be high enough at a prolonged time and the acid be concentrated, so that the volatilization of the materials be enhanced.
The surface area can be increased or made more efficient by reducing the carbonized and activated charcoal to fines and sieving with mesh sizes of 150Um or less (200Um, 240Um) etc, even though the sieving seems difficult and wastes time.
Since heat has an appreciable effect on bleaching by adsorption, it is advisable to heat the solution (oil and charcoal sample) on a hot plate at temperatures between 1500c and above, while the system has to be prouder with self-stirring mechanism (magnetic stirrers) for proper making of the solution while heating.
To separate the oil from the charcoal after the heating, filteration by centrifigation is better recommended so that the gradual fall of the of sample ensures pure product. A more efficient device for this should be provided since filteration using filter paper is very slow and lasts for several hours.
Furthermore, the time of heating has to be very optimum. Excessive heating at high temperature, hence denatuning the quality and colour of the final bleached oil. Hence, 8minutes was used in this work since it was observed that at this time, colour reduction still occurred.
And the measurement and analysis of the nature and colour of the crude palm oil and bleached one is recommended to be done using a sulphisticated equipment as the spectrophotometer which gives an approximate and accurate results.
Finally, the use of local adsorbent like charcoal made from bone, for bleaching recommended instead of the imported fullers earth where extra cost is incurred and hence reduces economic value of the products.
REFERENCES
- Materials and Technology Handbook: Oils and Fats Bleaching J.H De Bussy, London, 1975, Vol 2, Pp 92-101, Vol 5 Pp 188-193.
- Anderson Mare and Rubin Man: Adsorption of Inorganic at Solid-hquid Interface” An Arbor Scince Publishers, Michigam, USA; 1981 Pp 122-124.
- Asiedu J. T: Processing Tropical Crops ‘Technological approach, MacMillian Education Ltd, London, 1989, Pp 176-187.
- Wayne Bucher (WB consulting): “The Basis of Bleaching”, Bleaching 101. As Adopted from the Internet, June 2005.
- Cocks L.V and C. Van Rede: Laboratory Handbook for Oil and Fats Analysis, Academic Press Inc., London. Pp 221-238.
