1.palm oil refining

PEMURNIAN MINYAK SAWIT

Tek. Peng. Nabati 2 - Teti Estiasih - THP FTP UB

TUJUAN

Pemurnian (purification) bertujuan untuk menghilangkan senyawa ikutan yang sering disebut sebagai impurities (kotoran) dalam minyak

Perubahan minyak kasar (crude oil) menjadi minyak makan (edible oil)

Meliputi satu atau lebih proses berikut: degumming, netralisasi atau physical refining, bleaching, dan deodorisasi

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JENIS-JENIS IMPURITIES

Proses ekstraksi minyak menyebabkan sejumlah senyawa non trigliserida terbawa

Meliputi: asam lemak, gliserida, fosfatida, sterol, tokoferol, hidrokarbon, pigmen (klorofil, karoten), fragmen protein.

Jenis minyak yang berbeda: kotoran berbeda Contoh: minyak hewani, CPO dan PKO :

asam lemak bebas; minyak canola: klorofil Kotoran tertentu dikehendaki seperti sterol

dan tokoferol Tek. Peng. Nabati 2 - Teti Estiasih - THP

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PROSES PEMURNIAN

Menghilangkan senyawa yang tidak dikehendaki tertentu dengan meminimalkan kerusakan trigliserida

kotoran yang dihilangkan: asam lemak bebas, fosfatida, gum, dll

Proses pemurnian meliputi: bleaching (penghilangan warna), deodorisasi (penghilangan bau), refining (penghilangan asam lemak bebas), degumming (penghilangan gum)


Proses pemurnian PROSES PROSEDUR KOTORAN YANG DIHILANGKAN

Degumming H3PO4, H20, 70-80C

fosfolipid, trace metal, pigmen, karbohidrat, protein

Netralisasi NaOH (alkali lain)

Asam lemak, fosfolipid, pigmen, trace metal, senyawa bersulfur, oil-insoluble, water soluble

Pencucian H2O Sabun

Drying Na2SO4 anhidrat Air

Bleaching

Bentonit, adsorben lain

Pigmen, produk hasil oksidasi, trace metal, senyawa bersulfur, trace of soap

Filtrasi Spent of bleaching earth

Deodorisasi atau

Physical refining

Steam under reduced pressure

Asam lemak, MG dan DG, produk oksidasi, produk dekomposisi pigmen, pestisida, trace of oil-insoluble Tek. Peng. Nabati 2 - Teti Estiasih - THP

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Proses pemurnian secara kimiawi (kiri) dan fisik (kanan)

Storage of crude oil

Degumming Netralisasi Washing Drying Bleaching Filtration

Storage of partly refined oil

Bleaching Filtration

Storage of refined oil

Deodorization Polishing Cooling

Steam refining Polishing Cooling


By Product

PROSES BY-PRODUCT

Degumming Lesitin

Netralisasi

Pencucian

Asam lemak

Steam refining Asam lemak, mono dan digliserida


DEGUMMING

Pada proses ini minyak dipanaskan dengan penambahan asam fosfat

Perlakuan ini dilakukan jika sebagian besar senyawa berfosfor dapat terhidrasi dan menggumpal/tidak larut

By product dari proses ini adalah lesitin


NETRALISASI

Netralisasi merupakan perlakuan dengan alkali yang dilakukan pada kondisi tertentu sehingga kehilangan minyak netral (trigliserida) serendah mungkin

Pemurnian fisik (physical refining atau steam refining) merupakan alternatif lain untuk menghilangkan asam lemak bebas


BLEACHING

Terutama ditujukan untuk menjernihkan Dilakukan dengan pemanasan minyak (80-

180C) tetapi biasanya dilakukan antara 90-120 C.

Pada kondisi tanpa oksigen dengan menggunakan adsorben

Adsorben dapat berupa bentonit, fullers earth, karbon aktif, silika amorf

Tingkat penggunaan adsorben adalah 0.2-2.0% dari berat minyak

Minyak sawit dapat dibleaching dengan pemanasan suhu tinggi tanpa menggunakan adsorben Tek. Peng. Nabati 2 - Teti Estiasih - THP

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DEODORISASI ATAU PEMURNIAN FISIK

Merupakan langkah terakhir proses pemurnian yang bertujuan mendapatkan minyak yang tidak berbau dan daya simpan tinggi

Proses ini terutama bertujuan menghilangkan produk hasil oksidasi yang berperan terhadap bau minyak

Dilakukan dengan pemanasan suhu tinggi (170-250C) pada tekanan rendah dengan menggunakan uap air

Penggunaan suhu yang tinggi (lebih dari 220C beresiko terhadap streomutasi yang biasa terjadi pada asam linolenat


PEMURNIAN MINYAK SAWIT


EKSTRAKSI MINYAK SAWIT KASAR (CPO, CRUDE PALM OIL)

Beberapa tahapan ekstraksi minyak dari tandan sawit adalah:

1. Sterilisasi

2. Pelepasan buah (bunch stripping) 3. Digesti

4. Ekstraksi minyak

5. Klarifikasi dan Purifikasi

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Klarifikasi dan Purifikasi

CPO yang diekstrak mengandung air, padatan, dan partikel-pertikel terlarut yang harus dihilangkan

Partikel serat dipisahkan dari CPO dengan melewatkan minyak pada penyaring bervibrasi.

Pasir dan kotoran dipisahkan dengan cara pengendapan

Air dipisahkan dengan cara pengendapan atau sentrifugasi dilanjutkan dengan pengeringan vakum Tek. Peng. Nabati 2 - Teti Estiasih - THP

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Crude Palm Oil


PEMURNIAN dan FRAKSINASI


Komponen Minor

Komponen minor dalam CPO adalah fosfolipid, karbohidrat, trace metal, ALB, mono- dan digliserida, sterol, pigmen karotenoid, tokoferol, tokotrienol, produk hasil oksidasi, dan komponen-komponen berbau

Pemurnian mengurangi komponen pengotor yang dapat mempengaruhi mutu minyak akhir dengan tetap mempertahankan tokoferol dan tokotrienol

Proses pengolahan setelah ekstraksi adalah pemurnian dan fraksinasi


Refining Crude Palm Oil: Unit Processes


Refining Bleaching Deodorizing of Palm Oil


Neutralizing, Bleaching, Deodorizing of Palm Oil


A. PHYSICAL REFINING

Dilakukan dengan steam distillation pada suhu tinggi dan kondisi vakum

Terdiri dari dua tahap utama, yaitu pretreatment dan distilasi


1. Pretreatment

Dilakukan dengan proses degumming menggunakan asam fosfat dilanjutkan dengan bleaching

Bleaching dilakukan dengan proses adsorpsi pada kondisi vakum, suhu 90-130C, dilanjutkan dengan filtrasi

Pretreatment mengurangi kadar fosfolipid, trace metal, peroksida, dan karotenoid.


2. Degumming Pretreatment refers to the initial degumming of

crude palm oil with concentrated phosphoric acid and the subsequent adsorptive cleansing with bleaching clay.

Crude palm oil is dosed with phosphoric acid (8085% concentration) at a rate of 0.050.2% (of the feed oil), heated to 90110C, and given a residence time of 1530 min before passing to the bleacher where bleaching earth is added as a slurry.

The earth required ranges from 0.8 to 2.0%, depending on the quality of the crude oil.


The purpose of the phosphoric acid is to precipitate the nonhydratable phosphatides while the function of the earth is fourfold:

to adsorb the undesirable impurities such as trace metals, moisture, insolubles, and part of the carotenoids and other pigments

to reduce the oxidation products

to adsorb the phospholipids precipitated by the phosphoric acid

to remove any excess phosphoric acid present in the oil after degumming.


Removal of Phosphoric Acid

Complete removal of residual phosphoric acid in the bleaching stage is also critical as any slip through can result in the rapid rise of free fatty acid content and color of the final RBD oil

As a further assurance, a suitable quantity of calcium carbonate is often added after dosing of the bleaching earth to the degummed oil, to help neutralize the residual phosphoric acid Tek. Peng. Nabati 2 - Teti Estiasih - THP

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3. Bleaching

Bleaching is carried out under a vacuum of 2025 mmHg and at a temperature of 95110C with retention time of 3045 min

The slurry containing the oil and earth is then filtered to recover a clear, light orange color pretreated oil

Usually a small amount of diatomaceous earth is used to precoat the filter leaves to improve the filtration process.

As a quality precaution, the filtered oil is polished through another security filter bag in series, to trap any earth particles that escape through the first filter Tek. Peng. Nabati 2 - Teti Estiasih - THP

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Loss of Oil

This is essential as the presence of spent earth particles in the pretreated oil reduces the oxidative stability of the final RBD oil

The spent bleaching earth from the filter normally contains about 2040% oil, and this is the major source of oil loss in the refining process


4. Deodorization

The pretreated oil is then ready for deacidification and deodorization.

The pretreated oil is first deaerated followed by heating to 240270C in an external heat exchanger before pumping into the deodorizer, which is kept under a vacuum of 25 mm Hg

Superheated high-pressure steam is now commonly being used,


Temperatures above 270C are to be avoided to minimize loss of neutral oil, tocopherols/tocotrienols, and also the possibilities of isomerization and undesirable thermochemical reactions

Under such conditions and with the help of stripping steam, the free fatty acids, which were still present in the pretreated oil, are distilled together with the more volatile odoriferous and oxidation products such as aldehydes and ketones, which otherwise would impart undesirable odor and taste to the oil

At the same time, the residual carotenoids present are also thermally decomposed, and the end result is the production of a light-colored, bland RBD palm oil Tek. Peng. Nabati 2 - Teti Estiasih - THP

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Cooling after Deodorization

To maximize the recovery of thermal energy, the hot deodorized oil is heat exchanged against incoming pretreated oil to be cooled down to a temperature of 120150C

Further cooling is effected by water down to 5565C prior to storage

Antioxidant and citric acid, if required, are dosed into the RBD palm oil at this stage


DALMS/PFAD


Desirable Quality of Pretreated and RBD Palm Oil from the Factory


B. CHEMICAL REFINING

Also called caustic refining, chemical refining involves three stages:

(1) gum conditioning and neutralization

(2) bleaching and filtration

(3) deodorization.


Alkali refining sesuai untuk minyak dengan

kadar ALB tinggi Kelemahan alkali refining: terjadi

penyabunan minyak netral menyebabkan refining loss

Steam refining: hanya menghilangkan ALB sehingga refining loss rendah

Syarat minyak untuk steam refining: kadar fosfatida rendah dan tidak sensitif panas

Sebelum refining: fosfatida harus dihilangkan Tek. Peng. Nabati 2 - Teti Estiasih - THP

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1. Gum Conditioning and Neutralization

The crude oil is heated to a temperature of 8090C. Phosphoric acid of 8085% concentration is then dosed in at a rate of 0.050.2% (of the feed oil)

This serves to precipitate the phospholipids

After this, the degummed oil is further treated with a caustic soda solution


Neutralization A caustic soda solution of about 4 N (or 20 Be)

concentration with a calculated excess (based on free fatty acid content of the crude oil) of about 20%

The reaction between caustic soda and the free fatty acids in the degummed oil results in the formation of sodium soap, which is readily removed by a centrifugal separator

The lighter phase discharged consists mainly of neutralized oil containing 5001000 mg/kg of soap and moisture while the heavy phase is mainly soap, insoluble impurities, gums, phosphatides, excess alkali, and a small quantity of oil loss through emulsification

As an excess of alkali is used, it is unavoidable that a slight loss of neutral oil through saponification also occurs


Washing

The neutralized palm oil (NPO) is then washed with 1020% hot water to remove traces of soap still present

After another stage of centrifugal separation, the washed oil is then dried under vacuum to a moisture level below 0.05%.


2. Bleaching and Filtration

The neutralized palm oil is treated with bleaching earth in a similar manner as that described in physical refining

In this case, the earth also removes traces of soap that are present


3. Deodorization The neutralized and bleached oil is then channeled to the

deodorizer in a similar manner to that in the physical refinery

The oil is subjected to distillation at a temperature of 240260C and a vacuum of 25 mm Hg with direct steam injection

Under such conditions, residual free fatty acids, volatile oxidation products, and odoriferous materials are removed together with thermal decomposition of carotenoids

The final product, called neutralized, bleached, and deodorized (NBD) palm oil is then cooled down to 60C and passed through polishing filter bags before pumping to the storage tanks Tek. Peng. Nabati 2 - Teti Estiasih - THP

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Refining Factor

The efficiency of the refining process is estimated by the use of a refining factor (RF)


Desirable Quality of Freshly Produced Intermediate and Final Products in Alkaline Refining of Palm Oil


FRAKSINASI

Trigliserida utama dalam minyak sawit adalah oleodipalmitin dengan titik leleh 37C dan palmitodiolein dengan titik leleh 19C

Tujuan fraksinasi adalah menghasilkan fraksi olein yang cair (slip melting point 21.6C dan cloud point 8.8C) dan fraksi padat stearin

Fraksi olein digunakan terutama untuk minyak goreng dan minyak masak, sedangkan fraksi stearin digunakan untuk, margarin, shortening, dan minyak goreng

Fraksinasi dilakukan dengan dua proses yaitu dry fractionation dan detergent fractionation


Fractionation and PMF


Fatty Acid Compositions (%)


Melting and Solidification Characteristics


Dry Fractionation

Minyak dipanaskan pada suhu 70-75C untuk melelehkan inti-inti kristal

Minyak panas tersebut dimasukkan ke dalam crystallizer dan didinginkan pada suhu 18-20C selama 4-8 jam

Proses ini menghasilkan minyak dalam bentuk sluri

Fraksi padat dan cair dipisahkan dengan filtrasi membran


Detergent Fractionation

Pada proses ini pemisahkan fraksi padat dan cair dalam sluri dari crystallizer dilakukan dengan mencampur sluri dengan deterjen

Deterjen yang digunakan natrium lauril sulfat atau magnesium sulfat

Pada proses sentrifugasi fraksi olein yang lebih ringan terpisah dari fraksi akueous yang mengandung stearin

Fraksi olein kemudian dicuci dan dikeringkan, sedangkan fraksi stearin direkoveri dari fraksi akueous dan deterjen didaur ulang


Solvent Fractionation This process is the most expensive because of solvent loss, solvent

recovery equipment, much lower temperature requirement, and stringent safety features

The process involves the use of solvents such as hexane or acetone

The oil is first dissolved in the solvent followed by cooling to the desired temperatures to obtain the desired crystals

The miscella containing the partially crystallized oil and solvent is then filtered under vacuum suction in an enclosed drum filter

The olein miscella and stearin miscella are then separately distilled to remove the solvent and recover the fractions

Yield of olein is about 80%

The solvent process nowadays is only viable in the production of high value products such as cocoa butter equivalent or other specialty fats Tek. Peng. Nabati 2 - Teti Estiasih - THP

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Second Fractionation/ Double Fractionation

Dilakukan untuk mendapatkan superolein dengan titik leleh dan titik kabut rendah dan bilangan iodin tinggi

Palm Mid Fraction (PMF) diperoleh sebagai fraksi stearin dari fraksinasi kedua ini

PMF lebih lunak


Jenis Asam Minyak Sawit dan Fraksinya

Jenis Asam Lemak

Refined

Palm Oil

RBD Palm Olein

RBD Olein (Double Fractionation)

RBD Stearin

PMF

Laurat 0.2 0.2 0.1 0.3 0.1

Miristat 1.1 1.0 1.0 1.5 1.2

Palmitat 44.0 39.8 36.6 52.0 51.0

Palmitooleat 0.1 0.2 0

Stearat 4.5 4.4 4.0 4.9 5.6

Oleat 39.2 42.5 44.8 33.3 34.0

Linoleat 10.1 11.2 12.6 7.6 7.4

Lunolenat 0.4 0.4 0.2 0.1 0.1

Arakhidat 0.4 0.4 0.7 0.3 0.6

Jenuh 50.2 45.8 42.4 59.0 58.5

MUFA 39.2 42.5 44.8 33.3 34.0

PUFA 10.5 11.6 12.8 7.7 7.5 Tek. Peng. Nabati 2 - Teti Estiasih - THP FTP UB

Krakteristik Minyak Sawit dan Fraksinya

Karakteristik Refined

Palm Oil

RBD Palm Olein

RBD Olein (Double Fractionation)

RBD Stearin

PMF

Bil. iodin 53.3 58.0 61.4 44 42.5

Slip melting point (C)

36.0 21.6 19.0 44-56

Solid Fat Content (%)

5C 62.2 51.1 67.2

10C 50.3 37.0 16.7 61.2 76.1

15C 35.2 19.2 5.0 53.1 66.2

20C 23.2 5.9 3.1 43.4 52.1

25C 13.7 33.9 21.9

30C 8.5 27.0 18.3

35C 5.8 22.2 13.4

40C 3.5 17.3 7.9 Tek. Peng. Nabati 2 - Teti Estiasih - THP

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QUALITY ASSURANCE

The two main quality problems associated with palm oil are hydrolysis, leading to formation of fatty acids, and oxidation, leading to rancidity


Hydrolysis

The hydrolysis of palm oil is promoted by the presence of free moisture and heat and also by lipolytic enzymes endogenous to the plant tissue

This mode of deterioration occurs during the bruising of fruits in the harvesting and transportation of the FFB to the mill and also their extended storage under unfavorable conditions

In the case of oil during storage, the hydrolysis is attributed to a chemical reaction that is autocatalytic ith poor cold stability


Hydrolysis The presence of high FFA in crude palm oil is undesirable:

(1) reduces the yield of RBD palm oil through higher loss of PFAD by-product

(2) reduces the capacity of refining

(3) results in poor bleachability of crude oil and poor stability in the final product

Crude palm oil with high FFA content invariably also contains a high amount of partial glycerides, especially diglycerides

Interactions between the diglycerides and the triglycerides often lead to formation of eutectics resulting in poor crystal formation during fractionation, difficulty in separation of olein and stearin by filtration, and also in production of olein with poor cold stability


Oxidation

Oxidation of oils and fats is due to prolonged exposure to air

Palm oil is relatively more stable to oxidative deterioration than the polyunsaturated vegetable oils

In the presence of trace metals such as iron and copper, excessive oxidation at the olefin bonds of the oleic and linoleic acids can occur, resulting in rancidity

Highly oxidized crude palm oil is known to have poor bleachability and thus requires more bleaching earth and more severe refining conditions, and the final product will likely be of poor stability


Quality Assurance Measures in Plantation and Milling

Availability of goodquality crude palm oil is a prerequisite for the production of good-quality refined palm oil products

The criteria for good-quality crude palm oil are:

Low free fatty acid content

Low in oxidation characteristics

Good bleachability

Low in trace metals and insoluble impurities

Moisture content of about 0.150.20%

High in deterioration of bleachability index (DOBI) Tek. Peng. Nabati 2 - Teti Estiasih - THP

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DOBI = Deterioration of Bleachability Index

DOBI, which is defined as the ratio of the uncorrected absorbance values at 446 nm to that at 269 nm, was introduced as a quality parameter to differentiate the refinability of good- and poor-quality crude palm oil

The relation to quality is DOBI >3, good; 2.42.9, fair, and

Quality Control


Type Action

Raw material Each and every delivery must be carefully inspected to ensure that specifications are met and that the shipment is free from contamination. Good raw material is a prerequisite to good-quality product

FFB handling Minimize bruising and sterilize as soon as possible (24 hr)

Sterilization optimize conditions, avoid overheating, do not mix boiler condensate with crude palm oil

Clarification eliminate water and impurities; use hermetic system

Drying reduce moisture to 0.170.2% before storage

Quality Control


Type Action In-process materials

Regular analyses of important quality parameters will serve as a check that proper processing has been achieved

Process control Proper processing conditions (dosage of processing aids, temperature, pressure/vacuum, flow rate, etc.) must be closely adhered to and monitored to ensure the oil is processed correctly and to minimize undesirable side reactions. In order to assess process efficiency, the oil losses through spent clay or soapstock (as in the case of alkaline refining only) must also be monitored

Finished products Regular checks on the finished products must be carried out to ensure compliance to quality specifications before the products are permitted for discharge to storage or shipment

Crude Palm Oil Quality


PENGGUNAAN MINYAK SAWIT dan FRAKSINYA

Palm oil, palm olein, dan palm stearin masing-masing bersifat semisolid, cair, dan solid pada suhu 25C

Karena sifat plastisnya yang luas, minyak sawit digunakan secara luas dalam produk pangan dari yang bersifat cair sampai semisolid seperti margarin dan shortening


Penggunaan dalam Produk Pangan

Minyak goreng/masak Shortening dan lemak masak Vanaspati (vegetable ghee) Margarin Cocoa butter substitutes Es krim Coffee whitener Lemak untuk bakery dan biskuit Mie instan Filled milk Soup mixes Tek. Peng. Nabati 2 - Teti Estiasih - THP FTP UB

Penggunaan untuk Non Pangan

Oleokimia (asam lemak, fatty alcohols, fatty amines, gliserol, dan metil ester)

Deterjen dan surfaktan Sabun Lilin Pelumas Kosmetik Pelapis kaleng Bahan bakar diesel Plasticizer untuk plastik


Problem Solving-Small Group Discussion

Suatu perusahaan refinery minyak sawit mempunyai masalah:

1. Stabilitas oksidasi minyak goreng yang rendah

2. Minyak goreng bersifat keruh

3. Warna minyak kecokelatan

4. Aroma minyak yang tidak enak

Apa penyebab masalah tersebut (a), adakah kaitan masalah tersebut dengan kualitas CPO (b), tahap refining mana yang menyebabkan masalah tersebut (c), tindakan koreksi apa yang harus dilakukan (d)


1.palm oil refining

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