The document discusses various methods for refining fats and oils, including chemical refining, physical refining, miscella refining, and the Zenith process. Chemical refining uses an alkaline solution to saponify free fatty acids and is the most commonly used method. Physical refining uses steam stripping under vacuum to remove free fatty acids and other impurities. Miscella refining involves refining crude oil prior to solvent stripping in a solvent extraction plant. The Zenith process passes oil droplets down a column of sodium hydroxide solution and consists of acid treatment, neutralization, and bleaching steps.

1. REFINING OF FATS & OILS
(Oil Neutralization Process)
Dr.Raj Kumar Kudari
Professor
Hindu College of Pharmacy, Guntur Andhra Pradesh, India.
.

2. INTRODUCTION
Terminology is all the same
Neutralization/ Deacidification Chemical refining/Caustic
refining Alkali refining
Refining : In Europe and America
Edible oil refining is a series of procedures to
remove
solid impurities
free fatty acids
phospholipids
gels
waxes
pigments
odors etc. from vegetable oils.
Edible oil refining plant technology is divided
into physical refining and chemical refining.

4. INTRODUCTION cont’d
Objectives of Neutralization:
In addition to the removal of FFA (Free Fatty Acids) other
undesirable non - glyceride materials are also removed.
These are mainly:
Phospholipids (gums)
Oxidized products
Metal ions (e.g. iron, copper)
Color pigments (e.g. gossypol)
Insoluble impurities (e.g. meal fines)
There are 4 Processes of Refining:
1. Chemical Refining
2. Physical Refining
3. Miscella Refining
4. Zenith Process

5. 1. CHEMICAL REFINING
The most commonly used method.
The process is widely known as CAUSTIC
DEACIDIFICATION. The main purpose of
chemical refining is to saponify the FFA by an
alkaline solution.The addition of an alkali solution
to a crude oil brings about a number of reactions.
These soaps are removed by separators either by
static separation or centrifugal separation.
The steps in Chemical Refining are:
Degumming
Neutralization
Bleaching
Deodourization

6. Steps in Chemical Refining
I. DEGUMMING
Chemical
Water
Acid
Soft Degumming
Total Degumming
Enzymatic
Membrane
II. DEACIDIFICATION
Alkali
Physical
Re-esterification
Chemical
Enzymatic
Biological
Solvent Extraction
III. BLEACHING
Membrane Bleaching
Natural Adsorbants
Activated Adsorbants
IV. DEODORIZATION
Steam stripping
Adsorption

7. . These conventional deacidification methods
are not best suited for oils that contain more
than 8–10% FFA.
The basic unit operations in vegetable oil
processing have remained relatively
unchanged for the past 5–6 decades.

8. 1. Chemical Refining cont’d
Advantages
Successful reduction of FFA up to thedesired
level irrespective of FFA content in raw/crudeoil.
Can be used for reliably refining virtually all crude oils,
including oils of low quality
Soaps formed during deacidification have thecombined
effects of purifying, degumming and partially
decolouring the oils.
Disadvantages:
 considerable oil loss due to:
the hydrolysis of neutral oil by caustic
in the form of occlusion insoapstock.
 FFA content in the crude oil has a direct bearing on the
neutral oil loss
 Generates more waste which is difficult and expensive
treat

9. 2. Physical Refining
 Physical deacidification uses steam stripping
under vacuum, that removes FFA, unsaponifiable
substances, and pungent compounds.
 Steam stripping can convert the carotenoids and
remove FFAs, most off-flavors, and pesticides,
but the other impurities must be handled before
the distillation step.
 To obtain good-quality fats and oils with
physical refining, it is essential to have a
phosphorus content lower than 5 ppm before
steamstripping.

10. Advantages
Physical deacidification offers many advantages over alkali
neutralization such as:
 Oil losses are reduced, the quality of FFA is improved,
and the operation is simplified.
 It consumes less steam, water and power.
 Improved product yield, elimination of soapstock as well as
reduced effluent quantity.
 Disadvantages
 Certain oils contain impurities that cannot be adequately
removed by the pretreatment process to enable them to be
physically refined.
 It has been reported that physical deacidification reduces
the tocopherol content and destroys all carotenes present
in palm oil.
 Physical refining requires high temperature and high
vacuum, and often forms side reactionproducts.
2.Physical Refining cont’d

11. 3. Miscella refining
 The refining of crude oil in the solvent
extraction plant, prior to solvent stripping,
is termed as miscella refining.
 Miscella refining has been applied to a variety
of oils, including cottonseed, soybean,
sunflower, palm, coconut and tallow.

12. 3. Miscella refining cont’d

13. 3.Miscella refining
• Advantages:
Higher oil yield due to less occluded neutral
oil in the soapstock.
Elimination of the water-wash and vacuum
drying step
Extraction of the color pigments before
solvent
• stripping has set the color
Miscella does not easily emulsify and the
soap tends not to entrain oil.
Reduction in energy requirements due to
physical properties of miscella.
cont’d

14. 3.Miscella refining cont’d
Disadvantages:
 Equipment — All equipmentand facilities
must be explosion proof for solvent
handling.
 Maintenance — The equipment and facilities
must be well maintained to avoid excessive
solvent losses and accidents.
 Laboratory — More elaborate laboratory
facilities and staffing are necessary to
control this process.
 The soapstock can be sticky and awkward to
handle.
 Its being tied to a running solvent extraction
plant.

15. 4.Zenith Process
The process used for refining vegetable oils. It
involves passing droplets of oil down a column of
aqueous sodium hydroxide. The Zenith process
was developed in Sweden in 1960 to enable
better refining of only oilseed crop grown in that
country: rapeseed.
[Rapeseed (Brassica napus subsp. napus), also known
as rape, oilseed rape, is a bright-yellow flowering member
of the family Brassicaceae (mustard or cabbage family),
cultivated mainly for its oil-rich seed.]
The stainless steel continuous process consists
of three main refining steps, two of which are
semicontinuous to maintain the desired reaction
times.
Zenith plants are designed for crude oil
capacities in the range of 20-200 tons per 24 hrs.

16. 4.Zenith Process cont’d
In the Zenith Process, non-fatty substances are
removed from the oil by treatment with
concentrated phosphoric acid.
The acid treatment is claimed to remove
calcium and magnesium from the gums,
thereby transforming nonhydratable
phosphatides into a hydratable form.
In the neutralization step, the oil, in the form of
droplets 1-2 mm in diameter, is introduced into
the bottom of a vessel almost filled with 0.35 N
alkaline solution.
In this weak alkyl solution, soaps are quickly
and completely dissolved on formation.
• .

17. 4.Zenith Process cont’d
The final step in the refining process is
bleaching. Citric acid solution is added to the
neutralized oil and the soap splitting process
starts.
After drying the oil under vacuum, bleaching
earth is added and allowed to contact the oil
for at least 30 min with agitation.
It is claimed that it is not necessary to water
wash the neutralized oil, that refining losses
are reduced, and that refined oil quality is
excellent.
• .

18. These conventional deacidification methods are
not best suited for oils that contain more than
8–10% FFA.
The basic unit operations in vegetable oil
processing have remained relatively unchanged
for the past 5–6 decades.
.

19. Thank You