Notes: Food & Nutrition | EVS & Pedagogy Paper 1 for CTET & TET Exams - CTET & State TET PDF Download

Foods are the substances which are essential for growth and development of an organism. All living organism need food, some of organisms such as plant make their own food by process of photosynthesis while animals obtain their food from plants and other animal.

Nutrition

• Process of obtaining nutrients or food is called nutrition.
• Nutrients are the organic or inorganic substances which help in our survival and maintaining proper health.
• On the basis of the quantity required by the body nutrients are classified into two categories:
  1. Macro Nutrients: These nutrients are required by body in large amount. E.g. carbohydrate, fat and protein.
  2. Micro Nutrients: These nutrients are required only in minute or very small amount. e.g., minerals and vitamins. Micro nutrients basically help in regulation of different functions of body.

Food Products and Their Sources

Food is essential for providing nutritional support to organisms. It can come from plant or animal sources and contains vital nutrients like carbohydrates, fats, proteins, vitamins, and minerals. Some foods, like mushrooms, come from fungi, and fermented products like bread, cheese, and yogurt involve bacteria. Let's explore the sources of food in detail.

Plant Foods

Green plants are the primary sources of food, with around 2000 cultivated species, many having distinct cultivars.

Edible Parts of the Plant

Various parts of plants are edible:

• Roots: Modified roots like carrot, turnip, radish, and beetroot store food. Carbohydrate-rich roots are used for food, animal feed, and manufacturing starch, alcohol, and fermented beverages like beer.
• Stems: While the main function of stems is to provide support, some like sugarcane and coriander store food. Examples of modified stems include potato(stem tuber) and ginger(underground stem).
• Leaves: Green leaves like spinach, cabbage, and curry leaves are important sources of calcium.
• Seeds: Edible seeds are used as grains, pulses, and oil seeds. Examples include rice, wheat, jowar, and maize (grains), grams, peas, and beans (pulses), and groundnut, sesame, mustard, coconut, and sunflower seeds (oil seeds).
• Fruits: Ripened ovaries of plants, including seeds, fruits are vital for the diet. Some botanical fruits like tomatoes, pumpkins, and eggplants are consumed as vegetables.
• Vegetables: These include root vegetables (potatoes, carrots), leaf vegetables (spinach, lettuce), stem vegetables (bamboo shoots, asparagus), and inflorescence vegetables (globe artichokes, broccoli). Many herbs and spices are also flavorful vegetables.

Animal Product

Animals can be sources of food directly or indirectly through products they produce.

• Meat: Obtained directly from animals, including muscle tissue and organs.
• Animal Products: Includes milk, eggs, poultry, meat, and honey. Birds lay eggs that are commonly consumed, and bees produce honey, a popular sweetener.

Trophic Levels

Trophic levels indicate the position of an organism in a food chain, which shows the succession of organisms that eat one another. Food chains and webs typically have two or three trophic levels, with a maximum of four. 

Many consumers, including humans, feed at more than one trophic level:

• Primary consumers: When humans eat plants like vegetables.
• Secondary consumers: When humans eat animals like cows.
• Tertiary consumers: When humans eat fish like salmon. This makes humans omnivorous animals.

Food Chain

• Every organism needs to obtain energy in order to live. For example, plants get energy from the sun, some animals eat plants, and some animals eat other animals.

• A food chain is the sequence of who eats whom in a biological community (an ecosystem) to obtain nutrition. It starts with the primary energy source, usually the sun or deep-sea vents.
• The next link in the chain is an organism that makes its own food from the primary energy source, such as photosynthetic plants that make food from sunlight through photosynthesis. These organisms are called autotrophs or primary producers.
• There are two main types of food chains in nature: grazing food chain and detritus food chain.

1. Grazing Food Chain

• This type of food chain starts with living green plants, goes to grazing herbivores, and then to carnivores. Ecosystems with this type of food chain rely on solar radiation.
• Examples include the sequence phytoplanktons → zooplanktons → fish or grasses → rabbit → fox.

2. Detritus Food Chain

• This type of food chain starts with dead organic matter, then to microorganisms, and then to organisms feeding on detritus (detritivores) and their predators.
• Such ecosystems are less dependent on direct solar energy. An example is the decomposing litter in a temperate forest.

Food Web

• A food web is made up of several interconnected food chains, showing the various paths through which plants and animals are connected in an ecosystem.
• While a food chain follows a single path of who eats whom, a food web illustrates the many different paths through which energy flows in an ecosystem.
• For example, a hawk might eat a mouse, a squirrel, a frog, or other animals, and a snake might eat a beetle, a caterpillar, or other animals. These different feeding relationships create a complex web of interactions in the ecosystem.

Different Components of Food

There are different components of food namely carbohydrate, fats, protein, minerals, vitamins, roughage and water.

Carbohydrates

• Definition: Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen. They are a primary source of energy for all living beings.

Types of Carbohydrates: There are three main types of carbohydrates:

1. Monosaccharides: These are the simplest carbohydrates that cannot be hydrolyzed into smaller carbohydrates. The general formula for monosaccharides is (CH₂O)n.

• Examples of monosaccharides include:
  • Triose: e.g., Glyceraldehyde
  • Tetrose: e.g., Erythrose
  • Hexose: e.g., Glucose, Fructose, Galactose

2. Disaccharides: These are composed of two monosaccharide molecules. The general formula for disaccharides is (C₁₂H₂₂O₁₁).

• Examples of disaccharides include:
  • Sucrose
  • Maltose
  • Lactose

3. Polysaccharides: These are made up of many monosaccharide molecules. The general formula for polysaccharides is (C₆H₁₁O₅)n.

Common Sources of Carbohydrates

• Starch Sources:
  • Cereals (e.g., wheat, rice, maize)
  • Millets (e.g., bajra, jowar, barley)
  • Tubers (e.g., sweet potato, tapioca, potato)
• Sugar Sources:
  • Sugarcane
  • Beet root
  • Fruits
  • Milk
  • Honey
• Cellulose Sources:
  • Cell walls of fruits
  • Vegetables
  • Cereals

Functions of Carbohydrates

• Providing Energy: Carbohydrates are the main energy source in the human diet, providing 4 kcal of energy per gram. They are essential for metabolism, and unused energy is stored as glycogen in the body for later use.
• Preventing Ketosis by Sparing Protein: When carbohydrates are absent from the diet, stored proteins are used as an energy source. Proteins are vital for synthesizing enzymes, antibodies, and other essential molecules. Adequate carbohydrate intake prevents the breakdown of skeletal muscle and other tissues, thus preventing ketosis.
• Dietary Fiber: Dietary fibers such as cellulose, hemicellulose, pectin, and mucilage are essential for intestinal health. They aid in digestion and provide bulk to the diet.
• Flavour and Sweetness: Carbohydrates contribute sweetness to food. Different carbohydrates have varying levels of sweetness. For example, fructose is almost twice as sweet as sucrose, and sucrose is about 30% sweeter than glucose.
• Necessary for Fat Oxidation: Carbohydrates are needed to metabolize fats. They break down into oxaloacetic acid, which is necessary for fat metabolism. Without this breakdown, fats are converted into toxic ketones.

Fats

• Definition: Fat is one of the three macronutrients, along with carbohydrates and proteins. It provides heat and energy to the body. Fats are composed of carbon, hydrogen, and oxygen, with a lower proportion of oxygen compared to carbohydrates.
• Types of Fats: Fats can be classified into two main types:
• 1. Saturated Fatty Acids: These fatty acids contain only single bonds between carbon atoms. Examples of saturated fats include coconut oil and palm kernel oil.
• 2. Unsaturated Fatty Acids: These fatty acids contain one or more double bonds in the fatty acid chain. Examples of unsaturated fats include butter and ghee.
• Functions of Fat in the Body: Fats serve various important functions in the body:
• Providing Energy: When carbohydrates are not available, fats serve as a backup energy source. One gram of fat provides more than double the calories compared to protein and carbohydrates.
• Vitamin Absorption: Some vitamins, such as vitamins A, D, E, and K, are fat-soluble and require fat for absorption.
• Fat Storage for Subsequent Use: Excess energy consumed beyond the body's immediate needs is stored as subcutaneous fat under the skin and around vital organs. This stored fat serves as a reserve energy source and provides protection to organs.
• Maintaining Body Temperature: A thin layer of fat beneath the skin helps insulate the body and maintain body temperature.
• Protecting the Body: Fat layers surrounding major organs, such as the brain, heart, and bones, act as protective cushions, safeguarding these organs from external impacts and sudden movements.

Protein

A macromolecule with critical functions in the body.

Protein is a macromolecule that plays many critical roles in the body. It helps in the manufacturing and repairing of tissues. Proper development of bones, muscles, skin, nails, and hair requires protein. One gram of protein produces 4 kcal of energy.

Amino acids are the building blocks of proteins, and these amino acids are linked together in long chains. There are 20 different types of amino acids that can be combined to make a protein. Proteins are necessary for the formation of enzymes, hormones, hemoglobin, and antibodies. Our daily food should contain protein because it cannot be stored in the body for later use.

Combination of Protein

• Protein is a carbonic compound formed by various amino acids.
• The main components of protein are carbon, hydrogen, oxygen, and nitrogen, with smaller amounts of phosphorus and sulfur.
• Carbon constitutes 50%, hydrogen 7%, oxygen 23%, nitrogen 16%, sulfur 3%, and phosphorus 0.3% of protein.

Sources of Protein

• Protein is obtained from both animal and plant sources.
• Animals eat plant protein and convert it into a form suitable for their bodies.
• Humans use both plant and animal protein. Animal protein is more similar to human protein and is often considered better for consumption. Examples of animal protein sources include meat, fish, eggs, milk, and cheese.
• Some plant proteins are also very important for the body, such as soybeans, nuts, and groundnuts. Fruits and vegetables also contain protein, but in smaller amounts.

Functions of Protein

• Repair and Maintenance: Protein is considered the building block of the body. It is essential for the maintenance of body tissues, including the development and repair of hair, skin, eyes, muscles, and organs.
• Children require more protein per pound of body weight than adults because they are growing and developing new protein tissues. Pregnant women also need increased protein intake to support their child's development.
• Energy: Protein is a significant source of energy. It is necessary for the maintenance of body tissues and other vital functions. If protein is not needed due to sufficient intake of other energy sources such as carbohydrates, it will be used to create fat and become part of fat cells.
• Hormones: Proteins are involved in the creation of certain hormones that help regulate body functions involving the interaction of various organs. For instance, insulin, a small protein, regulates blood sugar levels through the interaction of organs like the pancreas and liver. Secretin is another example of a protein hormone that aids in digestion by stimulating the pancreas and intestines to produce necessary digestive juices.
• Enzymes: Protein enzymes are crucial for the creation of DNA and for increasing the rate of chemical reactions in the body. Most necessary chemical reactions would not proceed efficiently without enzymes. For example, some enzymes help digest large protein, carbohydrate, and fat molecules into smaller ones, while others assist in DNA creation.
• Transportation and Storage of Molecules: Proteins play a significant role in the transportation of certain molecules. For example, hemoglobin is a protein that transports oxygen throughout the body. Proteins like ferritin are also involved in storing certain molecules, such as iron in the liver.
• Antibodies: Antibodies, formed by proteins, help prevent various illnesses, diseases, and infections. These proteins identify and assist in destroying antigens such as bacteria, viruses, and other pathogens. Antibodies often work alongside other immune system cells, surrounding and containing antigens until they can be destroyed by white blood cells.

Vitamins

• Vitamins are chemical substances required by the body in very small amounts. They do not provide energy but are essential for proper metabolic functions, good health, and protection against diseases. For example, vitamins help keep our eyes, bones, teeth, and gums healthy.
• Many chemical reactions in our body would not occur without the presence of vitamins. Vitamin A and D are fat-soluble vitamins, while Vitamin C is a water-soluble vitamin. Vitamin D, a fat-soluble vitamin, is found in fish oil, eggs, milk, and milk products. The main source of Vitamin D is sunlight, which helps the skin produce this vitamin.
• Vitamin D is crucial for the body's use of calcium for bones and teeth. A deficiency of Vitamin D can lead to the disease Rickets.

Minerals

• Minerals are required by our body in very small amounts, which is why they are called micronutrients. Essential minerals include calcium, phosphorus, sodium, potassium, chlorine, sulfur, iron, iodine, and copper. Each of these minerals is necessary for proper growth and maintaining good health.
• Calcium and phosphorus are important for the health of bones and teeth. Calcium is found in milk, skimmed milk, buttermilk, cheese, green leafy vegetables, and ragi. Phosphorus is found in milk, cereals, pulses, fish, and meat. Children require relatively more calcium and phosphorus for the growth of their bones. Pregnant and nursing mothers also need increased amounts of these minerals.
• Iron is essential for the formation of hemoglobin in blood. Sources of iron include leafy green vegetables, nuts, jaggery, and other green vegetables. A deficiency of iron can lead to anemia.
• Iodine is necessary for the proper functioning of the thyroid gland and is required in very small amounts. A deficiency of iodine can cause goiter, where the glands in the neck become swollen. Iodine deficiency can also lead to mental retardation in children.

Roughage

• Roughage, a type of fiber found in fruits and vegetables, is mainly composed of cellulose. Although it doesn't provide nutrients, it is crucial for the regular movement of the bowels.

Functions of Roughage

• Facilitates bowel movement.
• Cleans the digestive tract and protects against digestive issues.
• Prevents constipation.
• Helps retain water in the body.
• Maintains optimal blood sugar and cholesterol levels.

Water

• Water is a vital component of our diet, constituting 75% of an infant's body and 70% of an adult's body. The body requires about 2-3 liters of water daily.

Functions of Water

• Essential for all cellular reactions involving energy production or utilization.
• Major constituent of blood, which transports substances throughout the body.
• Keeps the body hydrated; dehydration can cause thickening of the blood, slowing its movement and causing pain and cramps.
• Aids in digestion.
• Dissolves waste products for removal through urine.
• Helps maintain body temperature through sweating and evaporation from the skin.

Balance Diet

• A balanced diet provides energy and nourishment for proper growth and maintenance of the body. It includes various food groups in the right proportions, such as energy-giving foods, body-building foods, and protective foods.
• The components of a balanced diet vary based on age, sex, and physical activity.
• In addition to a balanced diet, regular exercise, fresh air, water, sunshine, and adequate physical and mental rest are essential for a healthy body.

Nutritional Needs

Nutritional Needs for Growing Children

• Extra protein for new tissue formation.
• More calcium and phosphorus for bone and muscle cell development.
• Vitamin A for healthy eyesight.
• Vitamin C for overall health.
• Vitamin D for strong bones.

Persons in Different Occupations

• Individuals engaged in hard physical work (e.g., rickshaw pullers, laborers, carpenters, mill workers) require energy-rich foods (carbohydrates and fats).
• Athletes also need a high-energy diet.

During Pregnancy and Lactation

Pregnant Women:

• Require extra nutrients to support the developing embryo.
• Need additional protein for tissue growth.
• Require more calcium and phosphorus for the baby's bone development.
• Need more iron for sufficient blood supply to the baby.
• Require extra carbohydrates for increased energy demands.

Lactating Mothers:

• Need a diet rich in proteins, calcium, and vitamins to meet the demands of milk production.

Depending Upon the State of Health

• Individuals recovering from illness need increased proteins, minerals, and vitamins to repair damage caused by the ailment.
• Those who have lost blood due to surgery or accidents require more proteins and iron to replenish blood levels.

How do We Make and Eat Food?

• We consume both cooked and uncooked food. Some foods, like most fruits and salads, can be eaten raw, while others, such as cereals, pulses, and most vegetables, need to be cooked before consumption.
• Cooking makes food easier to digest and helps eliminate germs. However, overcooking can destroy nutrients. There are three main methods of cooking.

Moist Heat Method

• Methods that use heat generated by water, including boiling, steaming, pressure cooking, and stewing.
• Boiling: Food is cooked in boiling water, coming into direct contact with it. Suitable for rice, eggs, dals, potatoes, meat, sago, and beetroot. Excessive boiling can drain minerals and vitamins.
• Steaming: Food is cooked by steam without direct contact with water, taking longer than boiling.
• Pressure Cooking: Food is cooked under pressure, increasing temperature and reducing cooking time, similar to steaming.
• Stewing: Food is cooked slowly in a closed pan with minimal liquid, retaining flavor.
• Simmering: Cooking food at a temperature just below boiling, useful for tenderizing foods over a long period.

Fry (Cooking by Fats)

• Cooking food using hot fat or oil, which can be heated to higher temperatures than water, cooking food quickly and making it tasty.
• Sautéing: Tossing food in a small amount of heated fat until partially cooked and it absorbs the fat.
• Shallow fat frying: Cooking food in a small amount of hot fat, turning it occasionally for even cooking.
• Deep fat frying: Submerging food in hot fat, cooking it quickly and making it crispy.

Shallow Fat Frying

• Shallow Fat Frying involves using a shallow pan, like a frying pan or griddle, with a small amount of fat.
• The food is turned over during frying to ensure even browning on both sides. The fat used is often absorbed by the food.
• Common preparations include parantha, omelette, tikkis, pancakes, etc.
• Foods like bacon and sausages, which contain sufficient fat, can be fried with little to no added fat.

Deep Fat Frying

• In Deep Fat Frying, food is completely immersed in hot fat, requiring a deeper utensil like a karahi and a large quantity of fat.
• The fat is heated in the karahi, and as it becomes hot, the food is added, cooking it quickly.
• Common preparations include poories, pakoras, cutlets, samosas, etc.
• During deep frying, it’s important to avoid overheating the fat, as it can decompose at high temperatures, affecting the taste and healthiness of the food.

Dry Heat Method

The Dry Heat Method involves cooking food without the use of water or oil, relying solely on heat. This method includes baking and roasting as primary techniques.

Baking

• Baking involves cooking food in hot air within an oven. The food is placed in a preheated oven, surrounded by hot air, which cooks it by dry heat.
• The oven is set to a specific temperature based on the type of food being baked, and this temperature is maintained throughout the cooking process.
• Common foods prepared by baking include cakes, biscuits, pies, pastries, puddings, vegetables, and potatoes.

Roasting

• Roasting involves cooking food uncovered in hot air, similar to baking but usually at higher temperatures. This can be done in a tandoor, oven, or a thick heavy pan.
• Foods like chicken and joints of good quality meat are often roasted with occasional basting, which involves adding a little fat to prevent drying and enhance flavor.
• Vegetables such as potatoes, sweet potatoes, and brinjals can be roasted directly over a flame or in an oven without the addition of fat.

Food Maintenance

Food maintenance involves ensuring hygiene during various stages of food production and consumption to prevent contamination. This includes production, handling, storage, distribution, cooking, and serving of all types of food.

Food Preservation

• Food storage is a crucial aspect of food maintenance. Foods can be classified into two types based on storage: perishable and non-perishable.
• Perishable foods, such as milk, vegetables, fruits, boiled rice, and most cooked foods, cannot be stored for long periods. These foods are stored in cold storage at very low temperatures to prevent spoilage caused by microorganisms.
• Non-perishable foods, like wheat, rice, and pulses, can be stored for long periods without spoiling. These foods are stored in dry storage at room temperature.
• Cold storage slows down the growth of microorganisms, helping to retain the nutritive value of perishable foods and reducing losses from spoilage.
• Dry storage for non-perishable foods should be clean, dry, cool, well-ventilated, and free from rodents and insects.
• Pasteurization is a method of preserving food by heating liquids, primarily milk, juice, and canned foods, to kill pathogenic microorganisms. This process was invented by Louis Pasteur.
• Common examples of bacteria that cause food poisoning include salmonella and clostridium, which can reproduce rapidly.
• To prevent food poisoning, careful treatment of food during production, processing, storage, and cooking is essential.

Recycle and Decomposition

• Food materials are subject to decomposition because they are of biological origin and will degrade naturally in the environment. Items like leftover food and vegetable or fruit peels can be decomposed and later used as manure.
• Many accessory articles used for storing or cooking food, such as utensils made of steel, other metals, and plastics, can be recycled. However, earthenware can be destroyed easily and will mix with the soil.