Topic 3 (SC)

UNIT 3: MODIFICATION PROCESS OF FATS AND OILS

1. Lesson Learning Outcome

• 3.0: Understand Modification Process of Fats and Oils

  • 3.1: Explain the modification process, which includes:

    • 3.1.1 Hydrogenation

    • 3.1.2 Inter-esterification

    • 3.1.3 Fractionation

    • 3.1.4 Plasticizing

    • 3.1.5 Tempering Process

  • 3.2 Importance of each process

  • 3.3 Principles of each method

  • 3.4 Changes occurring in each process

  • 3.5 Problem-solving involving modification processes

2. Key Modification Processes

2.1 Fractionation

• Definition: Process to remove solids by controlled crystallization and separation.

• Winterization: Traditional practice to avoid clouding of liquid fractions at low temperatures by crystallizing and filtering.

• Dewaxing: Clarifies oils containing trace amounts of clouding constituents.

  • Example: Salad oil; without winterization, waxes crystallize and make oil turbid.

2.2 Principles of Fractionation

• Oils and fats contain mixtures of triglycerides (TG) with varying melting points.

• When cooled carefully, highly saturated TG crystallizes first, allowing separation.

• Produced fractions include solid (stearin) and liquid (olein).

• Methods:

  • Cooling oil to supersaturation to create nuclei.

  • Lower cooling temperatures to form various crystal types: alpha (α), beta prime (β′), and beta (β).

3. Crystal Structure Characteristics

3.1 Polymorphism

• Polymorphism: Ability of a compound to exist in different crystalline forms (α, β′, β).

• Each form has unique crystalline structures and physical properties, though chemical composition remains the same.

3.2 Cooling Process Effect on Crystal Structure

• Fast Cooling:

  • Produces small crystals, difficult to separate, low density, low melting point, low stability (α).

• Slow Cooling:

  • Results in medium crystals that are easier to separate, with higher melting point and density, and better stability (β').

4. Hydrogenation

4.1 Process Overview

• Definition: Process that adds hydrogen to double bonds of unsaturated fatty acids to reduce them or produce fully saturated fats.

• Conducted by bubbling hydrogen gas through oils at temperatures of 150–200°C, under pressure, and using a catalyst.

4.2 Effects of Hydrogenation

• Converts unsaturated fatty acids to saturated ones.

• Alters melting points and other physical properties, often producing trans fatty acids during incomplete hydrogenation.

• Purpose: Improve thermal stability and oxidative stability of oils.

5. Inter-esterification

5.1 Process Definition

• Combines various oils and fats by repositioning fatty acids between triglyceride molecules.

• Maintains essential fatty acid content while modifying melting points and properties.

5.2 Applications and Advantages

• Used to produce hard fats suitable for deep frying or margarine.

• Preferred over partial hydrogenation due to lower trans fat content.

6. Plasticizing Process

• Helps fats attain their functional physical states.

• Allows stabilization and reorientation of fat crystals during the production of shortenings.

• Important in the production of products with desirable qualities like smoothness and creaminess (in margarine).

7. Tempering

• Process that stabilizes fat crystals and allows for their transformation into preferred polymorphic forms over 1-10 days.

• Essential for maintaining the functional properties of products; improper tempering negatively influences product quality.