Home 12th Class CBSE Class 12 Chemistry Notes: Chemistry in Everyday Life – Chemicals in...

CBSE Class 12 Chemistry Notes: Chemistry in Everyday Life – Chemicals in Foods

February 24, 2014

All those chemical which are added to food to improve its keeping qualities, appearance, taste, odour are called the food additives.
1. Food Colours
2. Flavoures and Sweetners
3. Preservative
4. Nutritional Supplemets.

ARTEFICAL SWEETNING AGENTS:-

Sucrose and Fructose used as normal sugar add to our calorie intake and promote tooth decay to avoid this we use artificial sweetners

a. Saccharin:-
It is most popular arteficial sweetner. It is insoluble in water. It is 550 times sweeter than sugar. It is not biodegradable and does not have any calotific value of food.

b. Aspartame:-
It is methyl ester of dipeptide derived from phenylalanine and aspartic acid. It is 100 times sweeter than sugar. It decomposes at baking or cooking temperature thus it can be only used in cold foods and soft drinks.

c. Alitame:-
It is morestable than as partame. It is nearly 2000 times sweet as sugar. It is difficult to controle the sweetness of food which they are added.

PRESERVATIVES:-

Chemical substances which are used to protect food against Bacteria, Yeasts and Moulds are called preservatives.
Examples:-

1. Sodium Benzoate:-

The most commonly used preservative sodium benzoate. It is used in soft drinks and acidic foods.
Sodium and Calcium propionates are used in breads and cakes as mould inhibitor.

2. Sodium Metabisalphite:-
Sodium or potassium metabisulphite is used for preserving James, Squashes, Pickles etc. other important preservatives are Sorbic acid, Epoxides, Sirca, Nitrogen, Hydroxy benzoate esters etc.

ANTIOXIDENTS:-
Chemical which are used to prevent the oxidation of fats in processed foods such as potato chips are called.
Antioxidents:-
Ascorbic acid (Vitamin C) and tocopherols (Vitamin E) are used as Antioxidents.

CLEANSING AGENTS:-

Soaps and Detergents:-
Chemical substances which concentrates at the surface of the solution or interfaces, farms surface Films, reduced surface tension of solution helps in removing dirt and dust by emulsibying grease are called surfactants. They are soaps and detergents.

Soaps:-

They are sodium or potassium salts of higher fatty acids such as lquric acid [C₁₁H₂₃COOH], steric acid [C₁₇H₃₅COOH] etc.
Soaps are formed by heating fat or oil with aqeous sodium hydroxide solution. This reaction is called sponification reaction.

Only sodium and potassium soaps are soluble in water and are used for the
cleanising purpose.