Processing of Edible
Oil (Palm Oil)
CHAPTER 3
Learning Outcomes
At the end of this chapter, students should be
able to:
• state basic refining process from crude oil until
intermediate products such as Palm olein & stearin
and others
• describes important parameters such pressure,
temperature and others in the processes
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3.1 Refining Process
Vegetables Oils and Fats
(Palm Oil)
• Palm Oil: composition
• C12:0 Lauric - 0.2%
• C14:0 Myristic - 1.1%
• C16:0 Palmitic - 44.0% saturated fatty acid
• C18:0 Stearic - 4.5%
• C18:1 Oleic - 39.2% unsaturated fatty acid
• C18:2 Linoleic - 10.1%
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Vegetables Oils and Fats
• Palm Oil characteristics:
Saponification value 195-205
Iodine value 44-58
Nonsaponifiable matter 0.5%
Melting point 36-40 °C
Refractive Index at 40 °C 1.453-1.456
Carotene Content 50-2000 ppm
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Input Output
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Characteristics of Crude Palm Oil
Impurities
• Hydrolytic
• Moisture, dirt, free fatty acids, partial glycerides and
enzymes
• Oxidative
• Metals, oxidation products, pigment, tocopherols, and
phospatides
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Characteristics of Crude Palm Oil
Impurities
• Catalyst poison
• Compounds containing nitrogen, sulphur & halogens
• Hydrocarbons
• Terpenes, resdin, waxes and unsaturated compounds
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Refining
• The aim of refining is therefore to convert the crude
oil to quality edible oil by removing objectionable
impurities to the desired levels in the most efficient
manner.
• And also to neutralized Free Fatty Acid present in
the crude oil
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Refining….
• The refining routes of palm oil is quite identical depends
on its characteristic:
• Product approach and refiners requirement
• Higher oil yield,
• Reduction of the use of chemical
• Reduction in water use
• Effluent 75 to 90% reduce
• Quality and acidity of crude oil
• Ability to remove soap stock
• Environmental legislation
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Refining….
• There are two routes are taken to process crude oil
into refined oil:
• chemical refining
• physical refining
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Refining….
• Characteristics of Crude Palm Oil….
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Refining….
Refining involves with four stages:
1. Pre-cleaning- neutralization by treatment of lye
2. Degumming- remove phospholipids
3. Bleaching- decolorization by adsorptive
treatment
4. Deodorization- stripping in vacuum
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Refining….
• Refining can be categorized into two types:
• Alkali/chemical refining
• Physical refining
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Chemical Refining
• During chemical refining, the free fatty acids are neutralized by
an addition of the appropriate quantity of lye.
• The resulting so-called ”soapstock”
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Chemical Refining
• The phosphatides and gums are absorb alkali and
coagulated through hydration or degradation
• Coloring is degraded & absorbed by gums or become
water soluble by the alkali
• Insoluble matters is trapped with others coagulable
materials.
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Chemical Refining
• Heat, time plus excess caustic can caused saponification
and producing glycerols and salts of fatty acid form the
neutral oil
• Separated either by decanting or - continuously - by
means of centrifuges. At this time, the non-hydratable
phosphatides are also separated.
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Chemical Refining
• Factors contribute of alkali refining success:
• NaOH(lye) strength/ concentration
• Mixing time
• Mixing energy
• Temperature
• NaOH excess.
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Chemical Refining
• Crude oil with high levels of phospatides such as canola,
soybean will be treated with food grade phosphoric acid
before mixed with caustic soda
• This step to ensure:
• Precipitate phosphatidic material
• Precipitate natural calcium & magnesium as insoluble
phospate
• Inactive trace metals such as iron and copper
• Reduce neutral oil losses.
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Physical Refining
• Physical refining, is a process which eliminates the need
for an effluent plant for the soap stock, involves
subjecting the oil to steam distillation under higher
temperature and vacuum for removal of the free fatty
acids . Expensive to removed
• Loss of neutral oil and reduce overall yield of crude oil.
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: Simplified Flowsheet of Physical Refining
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Physical Refining
• Suit when raw materials is low gums and high FFA, un-
saponifiable and others by stream stripping
• Need pretreatment with 2 steps:
• Addition of chemical to remove small amount of
gums
• Using steam distillation to remove FFA and
impurities.
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Physical Refining….
Low Phosphatides High Phosphatide
Crude fats & Oil Physical refining process flow Crude Fats & Oil
diagram
Acid Refining or
Degumming (Water Acid,
Enzymatic or Another
Process
Dry Degumming Dry Degumming or
Bleaching
Dewaxing, fractionation
Hydrogenation
Steam Distillation
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Deodorized Fat or Oil
Physical Refining
• Requirement of pre-treament:
• Phosphorus reduced to less than 30 ppm to support
on bleaching or dry degumming process
• After that trace level of element and phosphorus will
reduce approx. to 5 ppm
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Chemical vs Physical Refining
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Influence of initial Free Fatty Acid (FFA) content on the
direct refining cost.
Chemical
refining
Physical
Diriect refining cost
refining
Crossing point shows effective point at
(lower or higher) consideration to
swap any technique
1.2 % 2.0 %
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FFA %
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RESULTS
Colour of oil
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