5.2 food preservatives

Chapter 5 Chemicals for Consumers

B. FOOD ADDITIVES

• A natural or synthetic substance which is added to food to prevent spoilage or to improve its appearance, taste or texture

Types of Food Additives

Preservatives

Antioxidants

Flavourings

Stabilizers

Thickeners

Dyes

Preservatives

• Substances added to food to slow down or prevent the growth of microorganisms.

• Examples:

Salt, vinegar, sugar, sodium benzoate, sodium nitrate, sulphur dioxide

Preservative Example How it works

Salt Salted fish Draws the water out of the cells of microorganisms and retards the growth of microorganisms Sugar Jam

Vinegar Provides an acidic condition that inhibits the growth of microorganisms

Sodium nitrate or sodium nitrate

Burger, sausage, launcheon meat

Slow down the growth of microorganism

Benzoic acid or sodium benzoate

Sauce

Sulphur dioxide Fruit juice

Antioxidants

• Added to food to prevent oxidation that causes rancid fats and brown fruits.

• Examples:

butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), ascorbic acid (Vitamin C), tocopherol (Vitamin E) and sodium citrate

Antioxidant Example Function

Butylated hydroxyanisole (BHA)

Butylated hydroxytoluene (BHT)

Margarine To retard rancidity in oils

Ascorbic acid (Vitamin C) Fruit juice To preserve the colour of fruit

juice

Alpha tocopheral (Vitamin E)

Protects body tissue from damage caused by substances

called free radicals

Sodium citrate Cooked cured

meat To stop fats from turning

rancid

Flavouring

• Used to improve the taste of food and restore taste loss because of processing

• Examples:

Sugar, salt, vinegar, monosodium glutamate (MSG), aspartame and synthetic essences

Stabilizers

• Substance which helps to prevent an emulsion from separating out

• Examples:

Lecithin, mono- and di-glycerides of fatty acids

Thickeners

• Used to thicken foods

• Examples:

Pectin (jams and jellies)

Acacia gum (chewing gum, jelly and wine)

Gelatine (yogurt)

Dyes

• Used to add or restore the colour in food

• Examples:

Tartrazine, anthocyanin,

Advantages and Disadvantages of Using Food Additives

Advantages Disadvantages

Make food stay fresh longer, look nicer and taste better

Associated with serious diseases like cancer and asthma

Make food last longer Toxic effect