Ncert Notes - Class 6 Chapter 2 Components of Food

What Do Different Food Items Contain?

Different food items contain a variety of nutrients, including macronutrients (such as protein, fat, and carbohydrates) and micronutrients (such as vitamins and minerals). The specific nutrients that a food item contains will depend on the type of food it is and how it is prepared. For example, a serving of chicken breast contains a significant amount of protein, while a serving of broccoli contains a significant amount of vitamins and minerals.

What Do Various Nutrients Do for Our Body?

There are many different nutrients that are essential for the human body, and each one has a specific role to play in maintaining good health. Here is a brief overview of some of the key nutrients and their functions:

Protein: Protein is an essential nutrient that is used by the body to build and repair tissues, produce enzymes, and make hormones. It is also a source of energy.

Test for Proteins

There are several tests that can be used to detect the presence of proteins in a sample. One common test is the biuret test, which is based on the reaction between proteins and a copper sulfate solution. When a protein solution is mixed with the copper sulfate solution, the mixture turns violet in the presence of proteins.

Another test for proteins is the Bradford assay, which is based on the binding of a dye called Coomassie Brilliant Blue to proteins. When a protein sample is mixed with the dye, the dye binds to the proteins and the mixture becomes blue. The intensity of the blue color is directly proportional to the amount of protein in the sample.

Other protein tests include the bicinchoninic acid (BCA) assay and the Lowry assay. These tests are based on the reaction between proteins and chemicals that produce a colored product, the intensity of which is measured to determine the amount of protein in the sample.

Fats: Fats are an important source of energy and are needed to help the body absorb certain vitamins and minerals. They also play a role in maintaining healthy skin and insulation.

Tests for fats 

There are several tests that can be used to detect the presence of fats in a sample. One common test is the Sudan IV test, which is based on the ability of fats to dissolve certain dyes. When a sample containing fats is mixed with Sudan IV dye, the mixture will turn red if fats are present.

Another test for fats is the gravimetric test, which involves extracting the fat from a sample and weighing it. This can be done using a solvent such as hexane, which dissolves the fat but not other components of the sample. The fat can then be separated from the solvent and weighed to determine the amount of fat in the sample.

Other tests for fats include the Liebermann-Burchard test and the acid value test. The Liebermann-Burchard test is based on the reaction between fats and a solution of alcoholic potassium hydroxide, while the acid value test measures the amount of free fatty acids in a sample by titrating the sample with a base.

Carbohydrates: Carbohydrates are the body's main source of energy. They are found in a wide range of foods, including grains, fruits, vegetables, and dairy products.

Iodine Test for carbohydrates 

The iodine test is a common method for detecting the presence of carbohydrates in a sample. It is based on the fact that carbohydrates, especially starch, react with iodine to produce a blue-black color.

To perform the test, a small amount of the sample is mixed with a solution of iodine in a solvent such as water or ethanol. If carbohydrates are present in the sample, the mixture will turn blue-black. The intensity of the color is proportional to the amount of carbohydrates in the sample.

It is important to note that the iodine test is not specific for carbohydrates and can give false positive results for other substances that contain iodine or react with iodine. Therefore, the test should be used in combination with other methods to confirm the presence of carbohydrates.

Vitamins: Vitamins are essential for the proper functioning of the body's cells, tissues, and organs. Different vitamins have different functions, such as helping to build strong bones, maintaining healthy skin, and boosting the immune system.

Minerals: Minerals are inorganic substances that are needed by the body in small amounts to maintain good health. They play a variety of roles, including helping to build strong bones, regulating the body's fluid balance, and supporting the function of the muscles and nerves.

Water: Water is an essential nutrient that is needed by the body to function properly. It helps to regulate the body's temperature, lubricate joints, and transport nutrients and waste products around the body.

Fiber 

Dietary fiber is a type of carbohydrate that is found in plant-based foods. It is not digested by the body and passes through the digestive system largely unchanged.

There are two types of dietary fiber: soluble fiber and insoluble fiber. Soluble fiber dissolves in water and forms a gel-like substance, while insoluble fiber does not dissolve in water. Both types of fiber are important for maintaining good health.

Soluble fiber can help to lower cholesterol levels and regulate blood sugar, while insoluble fiber promotes regular bowel movements and helps to prevent constipation.

There are several tests that can be used to measure the fiber content of a food sample, including the crude fiber test, the neutral detergent fiber test, and the enzymatic-gravimetric method. These tests involve breaking down the sample and measuring the amount of fiber that remains after digestion.

Balanced Diet 

A balanced diet is one that provides the body with all the nutrients it needs to function properly. These nutrients include carbohydrates, proteins, fats, vitamins, minerals, and water.

To achieve a balanced diet, it is important to eat a variety of different foods from all the different food groups. The food groups are:

Grains: These include bread, rice, pasta, and cereals.

Fruits and vegetables: These include a wide range of fresh, frozen, canned, and dried fruits and vegetables.

Dairy: This includes milk, cheese, and yogurt.

Protein: This includes meat, poultry, fish, beans, and eggs.

Fats: These include oils, butter, and spreads.

It is also important to pay attention to portion sizes and to choose foods that are low in saturated fat, added sugars, and sodium.

Eating a balanced diet can help to maintain a healthy weight, reduce the risk of chronic diseases such as heart disease and diabetes, and support overall health and well-being.

Deficiency Diseases

Deficiency diseases are conditions that occur as a result of a lack of essential nutrients in the diet. These nutrients include vitamins, minerals, and other substances that the body needs to function properly.

Here are some examples of deficiency diseases:

Anemia: Anemia is a condition in which the body does not have enough red blood cells or the red blood cells are not functioning properly. It can be caused by a deficiency of iron, folic acid, or vitamin B12.

Scurvy: Scurvy is a condition that results from a deficiency of vitamin C. It causes the gums to bleed and the skin to develop painful, bumpy patches.

Rickets: Rickets is a condition that affects the bones, causing them to become soft and bend. It is caused by a deficiency of vitamin D, which is needed for the proper absorption of calcium.

Kwashiorkor: Kwashiorkor is a type of malnutrition that is caused by a deficiency of protein in the diet. It causes the body to break down muscle tissue and leads to a swollen abdomen and thin, weak limbs.

Deficiency diseases can be prevented by eating a varied diet that includes a range of different nutrients. In some cases, supplements may be necessary to ensure that the body is getting all the nutrients it needs.

Vitamins Sources 

Vitamins are essential nutrients that are required in small amounts to maintain good health. They can be obtained from the diet or from supplements.

Here are some examples of food sources of some common vitamins:

Vitamin A: This vitamin is found in yellow and orange fruits and vegetables, such as carrots, sweet potatoes, and mangoes. It is also found in liver, milk, and eggs.

Vitamin B: There are several types of vitamin B, including B1 (thiamin), B2 (riboflavin), and B3 (niacin).

Vitamin B can be found in a wide range of foods, including meats, whole grains, and fortified cereals.

Vitamin C: This vitamin is found in citrus fruits, such as oranges and lemons, as well as in strawberries, kiwi fruit, and leafy green vegetables.

Vitamin D: This vitamin is produced by the body when the skin is exposed to sunlight. It is also found in small amounts in fatty fish, such as salmon and sardines, and in fortified foods like milk and cereals.

Vitamin E: This vitamin is found in vegetable oils, nuts, and seeds. It is also found in leafy green vegetables and fortified cereals.

It is generally recommended to obtain vitamins from the diet, rather than from supplements, as it is easier for the body to absorb nutrients from food. However, in some cases, supplements may be necessary to ensure that the body is getting all the vitamins it needs.

Minerals sources 

Minerals are inorganic substances that are required by the body in small amounts to maintain good health. They can be obtained from the diet or from supplements.

Here are some examples of food sources of some common minerals:

Calcium: This mineral is found in dairy products, such as milk, cheese, and yogurt. It is also found in leafy green vegetables, such as broccoli and kale, and in nuts and seeds. 

Iron: This mineral is found in meats, poultry, and fish. It is also found in beans, nuts, and fortified cereals.

Magnesium: This mineral is found in whole grains, nuts, and leafy green vegetables. It is also found in dairy products and meats.

Potassium: This mineral is found in a wide range of fruits and vegetables, including bananas, avocados, and sweet potatoes. It is also found in meats and dairy products.

Sodium: This mineral is found in many foods, including meats, dairy products, and processed foods. It is also found in table salt.

It is generally recommended to obtain minerals from the diet, rather than from supplements, as it is easier for the body to absorb nutrients from food. However, in some cases, supplements may be necessary to ensure that the body is getting all the minerals it needs.