Chemistry in Everyday Life — Part 2: Chemicals in food: visual lesson, CBSE Class 12 Chemistry

Lesson

Chemicals in food

Part 2 — sweeteners, preservatives and antioxidants.

In this lesson you will

Explain why chemicals are added to food
Describe artificial sweetening agents and compare their sweetness
Describe food preservatives and how they work
Explain the role of antioxidants in food

Table of groups of food additives, their purposes and examples
Additive group	Purpose	Example
Artificial sweeteners	Sweetness with little or no energy	Aspartame, sucralose
Preservatives	Prevent spoilage by microbes	Sodium benzoate, salt, sugar
Antioxidants	Slow oxidation (rancidity)	BHT, BHA
Others	Colour, flavour, nutrients, emulsifiers	Food colours, vitamins

Concept

Why add chemicals to food?

Food additives preserve food, improve its appeal and add nutritive value. They include food colours, flavours and sweeteners, fat emulsifiers and stabilisers, flour improvers, antioxidants, preservatives and nutritional supplements (minerals, vitamins, amino acids). Except for nutritional supplements, they generally have no nutritive value.

Concept

Artificial sweetening agents

Sucrose and fructose are natural sweeteners but add calories. Artificial sweeteners give sweetness with little or no energy, useful for people with diabetes or those controlling weight. Sweetness is compared with cane sugar (sucrose = 1).

Table of artificial sweeteners with sweetness relative to sucrose and notes
Sweetener	Sweetness relative to sucrose	Notes
Aspartame	100	Unstable at cooking temperatures; used in cold foods and drinks
Saccharin	550	First popular sweetener; excreted unchanged
Sucralose	600	Trichloro derivative of sucrose; stable at cooking temperature; no calories
Alitame	2000	Very potent; sweetness hard to control

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