Food Technology

Food is a mixture of many different chemical components. The study of food technology involves an understanding of the changes that occur in these components during food preparation. Many physical and chemical reactions occur during food preparation. These reactions may be a result of the interaction between components, with the medium of cooking, and the environmental conditions such as heat, cold, light and air to which they are subjected during cooking. It also includes understanding the nutritive value of different foods and methods of preserving them during cooking.

Groups of food

The six major components of food are carbohydrates, proteins, fats, minerals, vitamins and water. To maintain good health, ingesting a diet containing these nutrients in correct amounts is essential. A balanced diet is one which contains different types of foods in such quantities and proportions so that the need for calories, proteins, minerals and vitamins is adequately met and a small provision is made for extra nutrients to withstand short duration of leanness. Nutritionists have grouped foods depending upon the nutrient content.

The five groups of food and their major nutrients

Group of food Nutrients
Cereal grains and products:
Rice,wheat,bajra,maize,jowar,rice flakes,wheat flour
fat,vitamin B1,vitamin B2,folic acid,iron,fibre
Pulses and legumes:
Bengal gram,black gram,green gram,(whole as well as dhals),Cowpea,peas,soyabean,beans
Energy,protein,invisible fat,vitamin B1,vitamin B2,folic acid,calcium,iron,fibre
Fruits and Vegetables:
Fruits:Mango,guava,tomato,papaya, orange,sweet lime,water melon
Vegetables:(green leafy) Amaranth,spinach,drumstick leaves,coriander leaves,fenugreek leaves
Others Vegetables:Carrots,brinjal,ladies fingers,capsicum,beans,onion,drumstick,cauliflower
Carotenoids,vitamin C,fibre
vitamin B2,Iron,fibre Vitamin B2,folic acid,calcium,iron,
fibre,carotenoids Carotenoids,folic acid, calcium,fibre
Milk and meat Products:
Protein,fat,vitamin B2,calcium Protein,fat,vitamin B2.
Fats and Sugar:Fats,Butter ghee,hydrogenated fat,cooking oils like groundnut,mustard,coconut,Sugar and jaggery Energy,fat,essential
fatty acids Energy


The process of subjecting foods to the action of heat is termed as cooking. Foods like fruits, vegetables and nuts are eaten raw but most of the foods are cooked to bring about desirable changes.

Preparations of food

Preparations of food includes cleaning, peeling and stringing, cutting and grating, sieving, soaking, processing, coating, blanching, marinating, sprouting, fermenting, grinding, drying and filtering.

  • Cleaning: Cleaning is applicable to vegetables, fruits and many others food products. Other aspect of cleaning is washing and is applicable to fruits, vegetables, cereals, pulses and non-vegetarian foods. Washing fruits render them dirt free. Washing cereals or dhals help to remove husk, mud and any other unwanted matter. Hard vegetables are scrubbed under cold running water.

  • Peeling and stringing: These methods involve the removal of nonedible or fibrous portion of fruits or vegetables. Peeling brings about loss of nutrients present under the surface of food, hence the product should be boiled or blanched and then peeled e.g. vitamin C in potatoes. Colour of beet root can be preserved better when it is cooked with the skin.

  • Cutting and grating: Dividing the food into smaller pieces is cutting. This helps in easy cooking. Various terms used under this are:

  1. Cut : To divide into pieces or to shape with knife

  2. Chop : To cut into no specified shape

  3. Mince : To chop very fine.

  4. Dice: To cut into small uniform cubes.

  5. Slice: To cut into uniform slices.

  • Sieving: Sieving is done to remove coarse fibres and insects and also in preparing cakes for blending of flour with backing powder.

  • Soaking: Soaking is done in water either plain or salted with sodium chloride or sodium bicarbonate.

Processing: Processing includes all the things to get food ready for cooking and serving. The various processes included under this are:

  • Mixing

  • Blending

  • Binding

  • Beating

  • Whipping

  • Folding

  • Mashing

  • Stuffing

Coating: Coating refers to covering a food with layer of crumbs, flour or other fine substances before cooking it. There are different types of coating.

  • Breading: This involves 3 steps. The product is first dredged in flour, then dipped in egg mixture liquids then in crumbs.

  • Battering: Battering means dipping the food product in batter. Batter is a semi liquid. It usually consists of an egg liquid mixture thickened with flour to achieve a smooth consistency.

  • Dredging: This means passing a food through a fine dry or powdery substance in order to coat it. Substances often used are flour, powdered almonds and bread crumbs.

Blanching: Blanching is plunging food into boiling liquid and immersing in cold water. This destroys enzymes present in food hence used as pre-preparation for preservation. Generally tomatoes, potatoes, almonds, carrots, and beans are blanched.

Marinating: Soaking a food in a marinade to add flavour or to tenderize it or both is marinating. Vegetables, fruits and meats are marinated with many flavour combinations. Meat marinade made up of oil, flavour builders and acid. Oil helps to hold natural juices of meat. Acid is used to tenderize by breaking down connective tissue. Vegetables like brinjals, onions, radish, bittergourd, potatoes and chillies are normally marinated.

Sprouting or Germination: All kinds of grams like green gram, bengal gram, peas and cereals like ragi and wheat are generally sprouted. Sprouted pulses are used in making salads and curries.

Fermentation: Fermentation is the process of breaking down of complex matter into simpler ones with the aid of enzymes and bacteria. This can be under aerobic or anaerobic conditions. Fermented foods are often more nutritious than their unfermented counterparts.

Grinding: This includes both wet and dry grinding. Wet grinding includes the grinding idli better and preparations of chutneys. Dry grinding is grinding spices for masala powders and wheat for wheat flour.

Drying: Drying or dehydrating is removal of moisture from food products. Removal of moisture helps to prolong the shelf life of the food.

Filtering: This process is generally done to remove dirt, unwanted particles or to remove moisture from food stuff. Food stuffs filtered are coffee, tea, rice, soups, fruit juices and tamarind water.

Roasting: This process should be grouped under actual cooking methods but certain recipes demand roasting as pre-preparation. Foods generally roasted are rava and vermicelli.

Main objectives of cooking:

  1. Improves the taste and food quality

  2. Destruction of micro-organisms

  3. Cooking increases the access to enzymes and improves digestibility.

  4. Increases variety. By cooking, same food can be made into different dishes.

  5. Cooking increases consumption of food by improving the texture and makes the food chewable.

  6. Increases availability of food. Raw egg contains avidin, which binds biotin making biotin unavailable to the body. By cooking, avidin gets denatured and biotin is available to the body.

  7. Concentrates nutrients: This may be due to removal of moisture or using combination of foods of due to cooking procedures.

Various methods cooking:
Classification of cooking methods:

Moist heat

Blanching,Steaming,Pressure cooking

Dry heat




(Food Technology)