13: Processing of oil and fats

Question 1

Describe the process of palm oil extraction.

Answer 1

1. Bunch reception: QC to check for FFA content
2. Sterilization: Inactivate enzymes (Lipase) and MOs, loosen fruits & palm kernel.
3. Threshing: Separation of oil palm fruits from the bunch via rotating drum
4. Digestion: Rotating beater arms of digester pound fruit to breakdown cell wall and release palm oil
5. Pressing: Wet method (hot water) or dry method (Screw press) to extract palm oil.
6. Clarification & Drying: Separate impurities from the crude palm oil.

Question 2

What are the four stages of crude oil clarification?

Answer 2

1. Separation of coarse particles using vibrating screen.
2. Separation of suspended solids in settling tank/decanter.
3. Purification: Separation of fine solids using decanter
4. Drying: vacuum evaporation to remove water residues

Question 3

Describe the purpose of palm oil refining.

Answer 3

Purpose:
- To increase stability of palm oil
- To improve nutritional properties of palm oil.

Question 4

Describe the process of palm oil refining.

Answer 4

1. Degumming by adding aqueous phosphoric acid
2. Deacidification by adding NaOH
3. Decolorization by adding activated clay
4. Deodorization by high T low P treatment.

Question 5

Describe the processing steps of virgin olive oil production.

Answer 5

1. Leaf removal & washing: prevent contamination and wear-and-tear on the mill.
2. Paste separation: Crusher breaks down cell wall to free oil droplets.. Malaxing: Slow mixing to gather large-sized oil droplets to form a continuous oily phase.
3. Liquid-solid separation: Separate liquid from the solid residues
4. Liquid-liquid separation: Remove residual water
5. Storage

Question 6

What are the separation systems available for solid-liquid separation of olive oil?

Answer 6

• Selective filtration using nickel or steel grid
• Extraction by pressure
• Extraction by centrifugation

Question 7

Describe fat crystal polymorphism.

Answer 7

• Fat crystal polymorphisms refers to the rearrangement of TAG molecules into different crystal lattice structures. Such as alpha, beta-prime and beta polymorphs.
• Polymorphisms takes place during crystallization
• Improve stability of fatty acids

Question 8

What are the methods of margarine production?

Answer 8

1. Using chilling drum: Thin layer of emulsion is placed on the cooling surface to allow rapid cooling without agitation. Solid margarine is scrapper of as thin films and rested in a silo before being kneaded via vacuum kneading.
2. Using scraped surface heat exchanger. Agitator mixes emulsifier and ingredients together. The mix is pasteurized in a plate heat exchanger. Pasteurized emulsion is pumped to the crystallization area with SSHE to crystalize. Pin rotor machine kneads the crystallized margarine to improve plasticity and softness.

Question 9

What are the factors affecting the hardness of butter?

Answer 9

• Degree of unsaturation of fat.
• Aging process & Crystallization temperature (fast cooling: large amount of small crystals produce firm butter)

Question 10

Describe the churning process of butter production.

Answer 10

• Vigorous agitation at cold temperature to breakdown fat globules and expel dissolved gas to form butter grains.
• Separation of butter from buttermilk.