This presentation includes all the general introduction on what is food, its main functions, its classifications. Foods can generally be classified according to different basis like on nutritive value, ease of spoilage, on origin, on acidity etc.

1. FOODS : CLASSIFICATION
OF FOODS
SUBMITTED BY,
ABEL JACOB THOMAS
MSc 1st YEAR

2. FOODS
• According to FSSAI, “food is defined as any substance whether processed , partially processed,
unprocessed, which is intended for human consumption and includes primary food, genetically
modified or engineered food or food containing such ingredients, infant food, packaged drinking
water, alcoholic drink, chewing gum, and any substance including water used into food during
its manufacture, preparation or treatment but doesn’t include any animal feed, live animals
unless they are prepared or processed for placing on the market for human consumption,
plants, prior to harvesting, drugs and medicinal products, cosmetics, narcotic or
psychotrotrophic substances”.
• Food refers to anything that nourishes the body. It would include solids, semi-solids and liquids
to which can be consumed and which help to sustain body and keep it healthy.
• Food is a substance which after ingestion, digestion and absorption is capable of being utilized
by body for various functions.
• Food supplies nutrients to the body that help us to maintain our nutritional status and also
improves health.

3. FUNCTIONS OF FOOD
• PHYSIOLOGICAL FUNCTION
• PSYCHOLOGICAL FUNCTION
• SOCIAL FUNCTION

4. PHYSIOLOGICAL FUNCTION
Physiological function can be further subdivided into:
a) Energy giving - The body requires constant supply of energy to carry out the involuntary
processes like circulation, respiration etc., and also other voluntary activities like jumping,
playing, household etc. Energy is also required to convert ingested food to useable nutrients.
b) Body building – The food eaten each day helps to maintain the structure of body and to
replace worn out cells of the body. Proteins and minerals play an important role in building
our body.
c) Regulation and protection - This function includes beating of heart, maintenance of body
temperature, water balance, clotting of blood, removal of waste products etc. Apart from
regulation food also helps in protecting our body from various diseases, infections and
injuries.
d) Maintenance of health – Foods contain certain phytochemicals and anti oxidants preventing
degenerative chemicals. Food plays an important role in prevention of cancer, controlling
heart diseases and in controlling diabetes mellitus.

5. PSYCHOLOGICAL FUNCTION
• Foods must also satisfy certain emotions needs. These include a sense of security, love and
attention. Everyone grows in a particular condition with its own food habit of that culture or
caste. The person begins to associate with that food commonly consumed by him as it gives a
sense of security and satiety.
SOCIAL FUNCTION
• Food and eating has significant social meaning. Sharing food with any other person implies
social acceptance. When we share a meal, we are expressing our acceptance of friendship and
respect to that person.
• Food is also a medium to show our happiness. Feasts are given at certain stages of our life like
birth, birthday, marriage etc.

6. Classification of foods
BASED ON NUTRITIVE VALUE
Food supplies nutrients to the body that help us to maintain our nutritional status and health.
The nutrients provided by foods include carbohydrates, proteins, fats, minerals, vitamins, and
water. Foods can be classified on the basis of nutritive value into ;
1. Cereals and Cereal products - They are an integral part of our diet and are the cheapest source
of energy. They contain carbohydrates and good amount of proteins. They are poor in lysine
and rich in methionine whereas pulses are rich in lysine and poor in methionine. When pulses
are mixed with some cereals, their protein quality improves through mutual supplementation.
2. Starchy roots and tubers – Potatoes, sweet potatoes provide carbohydrates and are thus
grouped along with cereals under energy giving foods. They do not provide protein as much as
cereals do.
3. Pulses and legumes – Nuts and oil seeds like groundnuts, sesame are included in this group.
Foodstuffs from this group provides major portion of proteins for vegetarians as pulses are
very good sources of vitamins and minerals. They also have high amount of vitamins and
minerals also but are poor in Vitamin C. But n sprouting they become rich source of this
vitamin also.

7. 4. Milk and meat products – They are also good sources of proteins. Milk provide minerals like
Calcium, Phosphorous and Vitamin A and Riboflavin. Eggs, meat, fish and chicken are sources
of first class proteins which can further be utilized for building of our body. They also contain
good amount of B group vitamins. Liver is a good source of Vitamin A and B 12. Egg and milk
also contain iron, calcium, phosphorous, fat and Vitamin A.
5. Fruits and Vegetables – This food includes fresh vegetables and fruits, they provide protective
nutrients to our body. Green leafy vegetables, orange and yellow couloured fruits and
vegetables provides carotenes. Vitamin C is found in fresh citrus fruits. Vitamin b is also found
in green leafy vegetables. Some fruits like peaches, pineapple and vegetables like fenugreek,
mustard seeds are exceptionally good sources of iron. They also add to the dietary fibre.
6. Fats, oils, sugars and jaggery – Fats and oils are very concentrated sources of energy providing
9KCal/ gram. They are used generally as a cooking medium and is hence a necessary part of
our diet. They increase the palatability of our food. They have high amount of carbohydrates.
And also are good sources of iron.

8.  BASED ON ORIGIN
Most food has its origin in plants. Some food is obtained directly from plants; but even
animals that are used as food sources are raised by feeding them food derived from plants.
Some foods not from plant or animal include various edible fungi, especially mushrooms.
1. Plant source – Many plants and plant parts are eaten as food and around 2000 plant species
cultivated for food. Seeds of plants are a good source of food for animals, including humans,
because they have nutrients for plants initial growth, including omega fatty acids.
2. Animal source – Animals are used as food either directly or indirectly by the products
produced from them. Meat is an example for direct product taken from animal which comes
from the muscle system or from organs. Milk, eggs, honey are some of the indirect foods
consumed from animals.

9. BASED ON EASE OF SPOILAGE
1. Non – perishable foods – They include any item that has long shelf life and doesn’t require
refrigeration to prevent spoilage. Dried and canned beans, nut butters, dried fruits and
vegetables, canned fish and poultry, nuts and seeds, grains, canned fruits and vegetables etc.
2. Semi – perishable foods – Foods that remain unspoiled for a fairly long period if not properly
stored or handled. They do not require refrigeration but still have limited shelf life. Potatoes,
onions, pumpkins etc are included in this category. They are usually kept on shelves in the
store room complex, where they get plenty of air circulation around them.
3. Perishable foods – Those foods that are likely to spoil, decay or become unsafe to consume if
not kept refrigerated at 4.5℃ or below, or frozen at 0℃ or below. They include meat, poultry,
fish, dairy products, most fruits and vegetables and all cooked left over.

10.  BASED ON ACIDITY
1. Low acid foods – Low acid foods are those foods having a finished equilibrium pH of greater
than 5.3 and a water activity of greater than 0.85. They include vegetables, ginger, oatmeal,
non-citrus fruits, egg whites etc. Acidified foods are low acid foods to which acids or acid
foods are added to reduce the pH to less than 4.6 .
2. Medium acid foods – Foods with pH between 4.6 and 5.3 are called medium acid foods. They
include bananas, cottage cheese etc.
3. Acid foods – They are the foods with ph 4.6 or lower. They include most citrus fruits, pickled
vegetables, jams, jellies etc. Most fruits and fermented products have acidity well below 4.6.
Some examples include citric acid in citrus fruits, malic acid in apples, lactic acid in cheese,
pickles, sauerkraut and dried sausage.
4. High acid foods – Some foods like dairy products, meat and poultry products, soft drinks,
have pH well below 3.5 and hence they are classified under high acid foods.