Food preservatives are substances added to food products to prevent spoilage caused by microbial growth and chemical changes. They help in extending the shelf life of food items, maintaining their nutritional value, and ensuring safety for consumption. Preservatives can be natural or synthetic and are used in various food products, including beverages, baked goods, dairy products, and processed meats.
Natural preservatives are substances derived from natural sources that help in preserving food. Common natural preservatives include:
Artificial preservatives are chemically synthesized substances added to food to prevent spoilage. Common artificial preservatives include:
Food additives are substances intentionally added to food to enhance its shelf life, appearance, flavor, or texture. They play a crucial role in the modern food industry, ensuring the safety, palatability, and appeal of processed foods. While some additives are naturally occurring, many are synthesized or extracted through chemical processes. Understanding food additives, their types, chemical properties, and safety profiles is fundamental for students preparing for JEE and other competitive exams.
Food additives can be broadly classified into the following categories:
Food colours are chemicals used to enhance or restore the appearance of food. They can be natural (derived from plant or animal sources) or synthetic (artificially produced). Adding colour to food makes it more attractive and can also signal freshness.
Caramel is one of the oldest and most widely used food colours, produced by controlled heating of carbohydrates such as glucose or sucrose. Caramel colouring is prevalent in soft drinks, sauces, and baked goods.
Preservatives are chemicals added to food to inhibit the growth of microorganisms, thereby extending shelf life and preventing spoilage. They can be classified as:
Key Examples:
Enzymes are biological catalysts that speed up chemical reactions during food processing, improving efficiency and product quality. They are crucial in the production of dairy products, baking, brewing, and fruit juice clarification.
Enzymes are preferred over harsh chemical treatments as they operate under mild conditions and are highly specific.
Artificial flavours are chemically synthesized compounds added to mimic natural flavours, while artificial sweeteners provide sweetness without the caloric value of sugar.
Natural Sweeteners: Sucrose (from sugarcane), fructose (from fruits), and honey are common examples.
Popular Artificial Sweeteners:
Sodium benzoate is the sodium salt of benzoic acid and is widely used as a preservative in acidic foods such as fruit juices, soft drinks, and pickles. It inhibits the growth of bacteria, yeast, and molds, thereby extending the shelf life of food products. Upon ingestion, sodium benzoate is metabolized into hippuric acid and excreted in the urine.
Potassium metabisulfite is used as a preservative in various food products, including fruit juices, wines, and dried fruits. It releases sulfur dioxide, which acts as an antimicrobial agent and antioxidant, preventing spoilage and discoloration. However, it is not suitable for preserving colored foods due to its bleaching effect.
Sorbic acid and its salts, such as potassium sorbate, are effective preservatives against molds and yeasts. They are commonly used in cheese, baked goods, and certain meat products to prevent spoilage and extend shelf life.
Propionic acid and its salts, like calcium propionate, are used to inhibit mold growth in bread and other baked goods. They help in preventing spoilage and maintaining the freshness of bakery products.
BHA and BHT are synthetic antioxidants used to prevent the oxidation of fats and oils in food products. They help in extending the shelf life of products like cereals, snack foods, and chewing gum by preventing rancidity.
Food preservatives work through various mechanisms to prevent spoilage:
Food preservatives are used in a wide range of products to ensure safety and extend shelf life:
The use of food preservatives is regulated by food safety authorities to ensure consumer safety. Preservatives must be used within specified limits, and their safety is continually evaluated through scientific research. Consumers are encouraged to read food labels to be aware of the preservatives used in food products.
(Session 2026 - 27)