Class 12 Chemistry Chemistry In Everyday Life Chemicals in Food

Chemicals in Food

  • Chemicals are added to the food for the following reasons:-
  1. Their preservation
  2. Enhancing their appeal
  3. Adding nutritive value in them.


  • Main categories of food additives are as follows:-
  1. Food colours


  1. Flavours and sweeteners

Sucrose (Natural sugar)


  1. Fat emulsifiers and stabilising agents
  2. Flour improvers - antistaling agents and bleaches
  3. Antioxidants
    1. Antioxidants prevent damage to the cells, cell proteins and lipids. They neutralize the free radicals which causes aging and degeneration of body.
    2. For example: - Vitamin E and Vitamin C etc. They are electron rich substances so they can denote electrons to free radicals which are causing age degeneration.
    3. They stabilize the age causing radicals.
  4. Preservatives
  5. Nutritional supplements such as minerals, vitamins and amino acids.


Artificial Sweetening Agents

  • Sucrose and fructose are the most widely used natural sweeteners.
  • But their intake increases calories in the diet and excess of them can cause tooth decay.
  • Ortho-sulphobenzimide, also called saccharin, is the first popular artificial sweetening agent. It is about 550 times as sweet as cane sugar. It appears to be entirely inert and harmless when taken.
  • Its use is of great value to diabetic persons and people who need to control intake of calories.


  • Aspartame is the most successful and widely used artificial sweetener. It is roughly 100 times as sweet as cane sugar.
  • It is methyl ester of dipeptide formed from aspartic acid and phenylalanine.
  • Use of aspartame is limited to cold foods and soft drinks because it is unstable at cooking temperature.
  • Sucralose is trichloro derivative of sucrose. Its appearance and taste are like sugar. It is stable at cooking temperature. It does not provide calories.


Food Preservatives

  • Food preservatives prevent spoilage of food due to microbial growth. The most commonly used preservatives include table salt, sugar, vegetable oils and sodium benzoate, C6H5COONa.
  • Sodium benzoate is used in limited quantities and is metabolised in the body. Salts of sorbic acid and propanoic acid are also used as preservatives.
  • There are 3 categories of food preservatives:-
    • Anti-microbial
      • It inhibits the growth of bacteria.
    • Anti-oxidant
      • They prevent damage to the cells, cell proteins and lipids. They neutralize the free radicals which causes aging and degeneration of body.
      • For Example: - BHT(butylated hydroxytoluene) and BRA(Butylated hydroxyanisole).
    • Anti-ripening
      • It will remove the oxygen from the substance. It is used to preserve fruits and vegetables.


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