ABSTRACT
This project work studied the refining of crude soya bean oil extracted from soya bean seed using alkali /caustic refining method. The work was carried out using phosphoric acid for the degumming /pretreatment process and sodium hydroxide for the neutralization /refining of the oil. Certain tests were carried out on both the crude and refined oil such as saponification value, acidic value, iodine value, specific gravity and viscosity, the results obtained after the tests include 42.075, 164.28, 589.05, 0.8944 and 0.038 respectively for refined oil and 44.88, 109.52, 448.8, 0.8148 and 0.035 respectively for the crude oil.
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TABLE OF CONTENTS
Title page … … … … … … … … … … i
Certification… … … … … … … … … … ii
Dedication… … … … … … … … … … iii
Acknowledgement… … … … … … … … … iv
Abstract… … … … … … … … … … … v
Table of contents… … … … … … … … … vi
List of table … … … … … … … … … … viii
List of figure… … … … … … … … … … ix
CHAPTER ONE
1.1 Introduction… … … … … … … … … 1
1.2 Background of the study… … … … … … … 3
1.3 Statement of the problem… … … … … … … 9
1.4 Objectives of the study… … … … … … … 9
1.5 Scope of the study… … … … … … … … 10
CHAPTER TWO
2.0 Literature Review… … … … … … … … 11
2.1 Historical Background of Soyabeans … … … … … 11
2.1.1 Composition of Soyabean … … … … … … 13
2.1.2 Soya Chemistry… … … … … … … … 14
2.2. Food Beans and Oil Beans… … … … … … … 15
2.2.1 Health and soya Foods… … … … … … … 17
2.3. Composition of Soyabean Oil… … … … … … 19
2.3.1 Triglyceric Structure… … … … … … … 20
2.3.2 Physical Properties of Soyabean Oil… … … … … 21
2.4. Recovery of Oil from Soyabean… … … … … … 24
2.4.1 Storage and Preparation of Beans… … … … … 24
2.4.2 Solvent Extraction… … … … … … … … 25
2.4.3 Oil Storage… … … … … … … … … 26
2.5. Edible Oil Processing… … … … … … … … 27
2.5.1 Basic Processing Operations and
Principle Edible Oil Product… … … … … … 28
2.5.2 Oil Degumming and Soyabean Lecithin… … … … 29
2.6. Refining Of Soyabean Oil… … … … … … … 31
2.6.1 Chemical (Caustic) Refining… … … … … … 33
2.6.2 Physical (Steam) Refining… … … … … … 35
2.7. Bleaching… … … … … … … … … … 36
2.7.1 Bleaching Process… … … … … … … … 38
2.7.2 Types of Adsorbents Used… … … … … … 40
2.8. Deodourization… … … … … … … … … 41
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2.8.1 Deodourization of Soyabean Oil… … … … … 42
2.8.2 Effect of Deodourization on Oil Quality… … … … 43
2.9. Evaluation of Finished Oil Quality… … … … … 43
2.9.1 Storage and Handling … … … … … … … 44
CHAPTER THREE
3.0 Materials and Methods… … … … … … … 46
3.1 Materials Used… … … … … … … … … 46
3.2 Equipments Used… … … … … … … … 46
3.3 Reagents Used… … … … … … … … … 47
3.4 Preparation of Reagents… … … … … … … 48
3.5 Procedures… … … … … … … … … 49
3.6 Testing of Oil… … … … … … … … … 50
3.6.1 Test for Saponification Value… … … … … … 51
3.6.2 Test for Iodine Value… … … … … … … 51
3.6.3 Test for Acidic Value… … … … … … … 52
3.6.4 Test for Specific Gravity… … … … … … … 52
3.6.5 Test for Viscosity… … … … … … … … 53
CHAPTER FOUR
4.0 Results and Discussion… … … … … … … 54
4.1 Results… … … … … … … … … … 54
4.2 Titration Readings… … … … … … … … 55
4.3 Discussion … … … … … … … … … 58
CHAPTER FIVE
5.0 Conclusion and Recommendation… … … … … 59
5.1 Conclusion… … … … … … … … … … 59
5.2 Recommendation… … … … … … … … 59
References … … … … … … … … … 60
Appendices… … … … … … … … … 62
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LIST OF TABLE
Table 2.1 Composition of soyabean oil… … … … … 19
Table 2.2: Average composition for crude
and refined soyabean oil… … … … … … 20
Table2.3 Selected physical properties of soyabean oil… … … 22
Table 2.4 Density of soyabean at several temperatures… … 22
Table 2.5 Smoke, flash and fire pointsâ€Ÿ
temperatures of soyabean oil … … … … … 23
Table 2.6 Classical refining of soyabean oil … … … … 32
Table 3.1 Degummed soyabean oil with different
quantities of sodium hydroxide … … … … … 50
Table 4.1 Result of the degummed soyabean oil… … … … 54
Table 4.2 Result of the canstic refining of soyabean
oil with different quantities… … … … … … 54
Table 4.3 Test results of the properties of the
refined oil and crude oil. … … … … … … 55
Table 4.4 titration reading of saponification value of refined oil… 55
Table 4. 5 titration reading of Iodine value of refined oil … … 56
Table 4.6 Titration reading of Acidic value of refined oil… … 56
Table 4.7 titration reading of saponification value of crude oil… 56
Table 4.8 titration reading of iodine value of crude oil… … 57
Table 4.9 titration of acidic value of crude oil… … … … 57
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LIST OF FIGURE
Fig 1:1-Generation flow sheet for refining and processing
fats and oils… … … … … … … … … 4
Fig 2:1 Front View of Soyabean Seed … … … … … … 12
Fig 2.2 A general outline of the soyabean food use based
on classification of oil and food Bean… … … … … 16
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CHAPTER ONE
1.1 INTRODUCTION
Refining of vegetable oils is essential to ensure removal of germs, phosphatides and free fatty acids (F.F.A) from the oil, to impact uniform colour by removal of colouring pigments and to get rid of unpleasant smell from the oil by removal of odiferous matter.
Refining is carried out either on batch operation or as continuous operation. With certain oils even physical refining can be carried out instead of chemical.
For processing less than thirty tones of oil per 24 hours, and when oil has F.F.A content of 1 percent or less normally batch process is recommended. Batch process involves low capital investments, simplicity of operation and low maintenance, making refining economically a viable proposition even at capacity as low as 10 tonnes per 24 hours. (According to Dietary fats and oils in Human Nutrition. (Rome 1977)).
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Soyabean oil is produced from the seed of the legume called soja max or calyclue max. The seed has an oil content of about 20%, it is the highest volume vegetable oil produced in the world. The crude oil is obtained by pressing or solvent extraction method. The main uses of the oil after refining, bleaching and deodorization and partial hydrogenation are in the manufacture of Magrine and shortening. The unhydrogenated oil is also used in blends with other oil but its tending to revert when exposed to air or higher temperatures limits its use. (Hand book of industrial chemistry, Reigel et al, (2003)).
Soyabean oil is also used extensively in the manufacture of drying oil products.
Crude soyabean oil of good quality has a lighter amber colour which upon alkali refining is reduced to the light yellow colour of most vegetable seed oils. Soyabean oil produced from green or immature beans may contain sufficient chlorophyll to have a greenish cast but this is not usually very evident until after the yellow red pigment of the oil have been bleached in hydrogenation (G.S Breck and S.C Bhatia, 2008).
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The crude oil particularly that obtained by solvent extraction contains relatively large amount of non-glyceride materials consisting chiefly of phosphatide. They are removed by water washing during refining processes. The phosphatides removed by water washing are converted to soya lecithin. The free fatty acid content of good crude soyabean oil like that many other vegetable oil is slightly in excess of 0.5 percent. (Hand book of Industrial chemistry,Reigel et al (2003)).