The Preservation Of Foods Essay Research Paper

The Preservation Of Foods Essay, Research Paper

The preservation of food.

Different government organisation, such as the world Health (WHO) and the United Nations Foods and Agriculture Organisation (FAO) have different definitions of food additives.

In laymen terms, a food additive is any substance added to food.

Definition:

” Any substance the intended use of which or may reasonably be expected to result directly or indirectly in its becoming a component to otherwise affect the characteristics of any food ” Mechanisms of action of food Preservation procedures, G.W.Gould. page 2

The food Protection committee of the institute of medicine’s Food and Nutrition Board Defines and additive as a ” substance or mixture of substance, other than a basic foodstuff, which is present in a food as a result of any aspect of production, processing storage, or packaging “.

Types or different form of food preservatives

Food preservatives are classified into two main groups: antioxidants

and antimicrobials,

+ Antioxidants are compounds that delay or prevent the deterioration of foods by

oxidative mechanisms. For example, enzymes called phenolases catalyse the oxidation of certain molecules (e.g., the amino acid tyrosine) when fruits and vegetables, such as apples, bananas, and potatoes, are cut or bruised. The product of these oxidation reactions, collectively known as enzymatic browning, is a dark pigment called melanin. Antioxidants that inhibit enzyme-catalysed oxidation include agents that bind free oxygen (i.e., reducing agents), such as ascorbic acid (vitamin C), and agents that inactivate the enzymes, such as citric acid and sulphites.

+ Antimicrobial agents inhibit the growth of spoilage and pathogenic micro-organisms

in food. Antimicrobials are most often used with other preservation techniques, such as refrigeration, in order to inhibit the growth of spoilage and pathogenic microorganisms. Sodium chloride (NaCl), or common salt, is probably the oldest known antimicrobial agent. Organic acids, including acetic, benzoic, propionic, and sorbic acids, are used against micro-organisms in products with a low pH. Refer to the fig 1 in appendix to see a list of common preservatives used in the food industry.

What are the main reasons for food preservatives.

Food Preservatives are used in food for four main reasons.

1. To maintain Product consistency.

Emulsifiers give a product a consistent texture and prevent them from separating. Stabilisers and thickeners give smooth uniform texture. Anti-caking agents help substance such as salt to flow freely.

2. To maintain palatability and wholesomeness.

Preservatives retard product spoilage caused by mould, fungi or yeast. Bacterial contamination can cause foodborne illness, including life-treating botulism. Antioxidants are preservatives that prevent fats and oil in baked and other good from becoming rancid or development an off flavour. They also prevent cut fresh fruits such as apples from turning brown when exposed to air.

3. To provide controlled acidity.

Some food preservatives like sorbic acid help modify the acidity and alkalinity of foods for proper flavour, taste and colour.

4. To enhance flavour or impact desired colours.

Many spices and natural and synthetic flavour enhance the taste of foods. Colours like wise enhance the appearance of certain foods to meet customer expectations. In addition, many substances added to foods may seem unheard of when listed on the ingredient label, but are actually quite familiar. For example, ascorbic acid is another name for vitamin C, alpha is another name for vitamin E and beta-carotene is another source of vitamin A

Types of food Preservation techniques

Low-temperature preservation

Storage at low temperatures prolongs the shelf life of many foods. In general, low temperatures reduce the growth rates of microorganisms and slow many of the physical and chemical reactions that occur in foods.

The life of many foods may be increased by storage at temperatures below 4 C (40 F). Commonly refrigerated foods include fresh fruits and vegetables, eggs, dairy products, and meats. Some foods, such as tropical fruits (e.g., bananas), are damaged if exposed to low temperatures. Also, refrigeration cannot improve the quality of decayed food; it can only retard deterioration. One problem of modern mechanical refrigeration–that of dehydration of foods due to moisture condensation–has been overcome through humidity control mechanisms within the storage chamber and by appropriate packaging techniques.

Salt and Nitrites

Brine is a combination of high concentration of salt, in a water solution.

Brine is used as a preservative and is also used a pickling agent. In refrigeration and cooling systems, brine is used as heat-transfer media because of the low freezing temperatures or as vapour-absorption agents.

SODIUM CHLORIDE (chemical formula: NACL), mineral substance is of a great importance. The meatpacking, sausage-making, fish-curing, and food-processing industries use salt as a preservative or seasoning or both. It is employed for curing and preserving hides and as brine for refrigeration. Salt decreases the moisture in meats available to

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