Fat & Oils In Food Science

FAT & OILS

The fats molecules is composed mostly of hydrogen atoms attached to carbon with fatty acid.

A. Classification (based on the origin and degree and degree of saturation)

Based on the origin

     1. Plant fats

         This fats gets from plants.

     2. Animal fats

         This fats gets form animals and its products.

Based on the degree of saturation

      1. Saturated fats (SFAs) 

         When all the empty or parking space are filled with hydrogenated atoms and do not have double bond, this fats is called saturated fats. Saturated fats are firmer at the room temperature and those fats have 16 and more carbon atoms chain then have a high melting point.

          
          Present in mainly animal fats such as meat, seafood, egg yolks, milk and milk based products. Some plants have high saturated fats are palm oil, and coconut oil.

      2. Unsaturated fats (UFAs)  

          Unsaturated fatty acids are fluid at room temperature. These are generally unstable where addition of hydrogen or oxygen or reactive substances can take place. This process  can cause flavor reversion and rancidity. 

          Monounsaturated fats (MUFAs) 

         When fatty acid carbons chain have one parking or empty space and have one & more double bond, is called a monounsaturated    fats. Present in olive oils, canola, peanuts, and rice bran etc.

         Polyunsaturated fats (PUFAs)

         When fatty acid carbons chain have two or more empty or parking space and have one & more double bond, is called a polyunsaturated fats. Present in corn, sunflower and soybeans etc.

Based on the dietary requirements

      1. Esssential 

          Those fats that are not synthesized by our body but required in our diet.

      2. Non-essential

          Those fats that are synthesized by our body but not required in our diet.

Based on the solubility

      1. Soluble fats

      2. Non-soluble fats

B. Autoxidation ( factors and prevention measures )

Rancidity

    Rancidity is process that deterioration of oils and fats part of  a food which gives bad odours and flavours in foods.

Rancidity have two types:

     1. Hydrolic rancidity

     2. Autoxidation

         It is also called Oxidative rancidity.

Factors of autoxidation 

Prevention of autoxidation  

C. Flavour reversion

     Flavour reversion means oxidative deterioration of edible fats.

Factors of Flavour reversion

     1. Heat

     2. Oxygen

     3. Reaction with metal during cooking

     4.

Prevention of Flavour reversion

     Adding EDTA ( Ethylene dioxide tetra acetic acid )

D. Refining, Hydrogenation & winterisation  

Processing of Fats

1. Refining

2. Hydrogenation

    When unsaturated fats are reacte with hydrogen in the presence of catalyst such as nickel, pt, and pd and converted into saturated fats called this process, hydrogenation.

This fatty acids is harder that unsaturated fats on the room temperature.

3. Winterization

4. Fractionation

E. Effect of heating on fats & oils with respect to smoke point

     When fats & oils are frying at high temperature then fats and oils undergo polymerization and hydrolysis of the fatty acids and releasing glycerol.

This temperature known as Smoking Point of Fats and Smoking Point.

F. Commercial  uses of facts ( with emphasis on shortening value of different fats)