SPM Chemistry

Preservative

Preservative

  1. Food preservatives are classified into two main groups: antioxidants and antimicrobials
  2. Antioxidants are compounds that delay or prevent the deterioration of foods by oxidative mechanisms.
  3. Examples of antioxidants are ascorbic acid (vitamin C) and citric acid.
  4. Antimicrobial agents inhibit the growth of microorganisms in food.
  5. Examples of antimicrobials are acetic acid (vinegar), sulphur dioxide, sodium sulphite, benzoic acid, sodium benzoate, sodium nitrite and sodium nitrate.
  6. Table below shows the uses of a few types of preservative that common used in our daily life.
PreservativeUses
Sulphur dioxide, Sodium sulphitePrevent browning of fruit juice
Keep the colour of vegetables
Benzoic acid, Sodium benzoatePreserve sauces. Example, tomato and chilli sauce.
Sodium nitrite, Sodium nitratePreserve meat, canned food and cheese.
Make the food look fresh.
Advantage and Disadvantage of Food Additives

Advantage 

  1. Can prevent the growth of microorganisms and hence keep food for a longer time.
  2. Improve nutritional in food
  3. For medical purposes. For example, artificial sweetener diabetes patient.

Disadvantage 

  1. taking with excess quantities can cause health problem.
  2. has low nutritional value.