`=>` Chemicals are added to food for

(i) their preservation

(ii) enhancing their appeal and

(iii) adding nutritive value in them.

`=>` Main categories of food additives are as follows :

(i) Food colours
(ii) Flavours and sweeteners
(iii) Fat emulsifiers and stabilising agents
(iv) Flour improvers - antistaling agents and bleaches
(v) Antioxidants
(vi) Preservatives
(vii) Nutritional supplements such as minerals, vitamins and amino acids.

`color{red}("Note ")` : Except for chemicals of category (vii), none of the above additives have nutritive value.

● These are added either to increase the shelf life of stored food or for cosmetic purposes.

`=>` Natural sweeteners, e.g., sucrose add to calorie intake and therefore many people prefer to use artificial sweeteners.

`=>` Ortho-sulphobenzimide, also called saccharin, is the first popular artificial sweetening agent.

● It has been used as a sweetening agent ever since it was discovered in 1879.

● It is about `550` times as sweet as cane sugar.

● It is excreted from the body in urine unchanged.

● 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.

`=>` Some other commonly marketed artificial sweeteners are given in Table 16.1

`color{green}("Aspartame ")` : It 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.

`color{green}("Alitame ")` : It is high potency sweetener, although it is more stable than aspartame, the control of sweetness of food is difficult while using it.

`color{green)("Sucrolose ")` : It is trichloro derivative of sucrose.

● Its appearance and taste are like sugar.

● It is stable at cooking temperature.

● It does not provide calories.

`color{green}("Definition ")` : Food preservatives prevent spoilage of food due to microbial growth.

● The most commonly used preservatives include table salt, sugar, vegetable oils and sodium benzoate, `color{red}(C_6H_5COONa)`.

● 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.