Preservative
- Food preservatives are classified into two main groups: antioxidants and antimicrobials
- Antioxidants are compounds that delay or prevent the deterioration of foods by oxidative mechanisms.
- Examples of antioxidants are ascorbic acid (vitamin C) and citric acid.
- Antimicrobial agents inhibit the growth of microorganisms in food.
- Examples of antimicrobials are acetic acid (vinegar), sulphur dioxide, sodium sulphite, benzoic acid, sodium benzoate, sodium nitrite and sodium nitrate.
- Table below shows the uses of a few types of preservative that common used in our daily life.
| Preservative | Uses |
| Sulphur dioxide, Sodium sulphite | Prevent browning of fruit juice Keep the colour of vegetables |
| Benzoic acid, Sodium benzoate | Preserve sauces. Example, tomato and chilli sauce. |
| Sodium nitrite, Sodium nitrate | Preserve meat, canned food and cheese. Make the food look fresh. |
Advantage and Disadvantage of Food Additives
Advantage
- Can prevent the growth of microorganisms and hence keep food for a longer time.
- Improve nutritional in food
- For medical purposes. For example, artificial sweetener diabetes patient.
Disadvantage
- taking with excess quantities can cause health problem.
- has low nutritional value.