Biology
■ Biology and its Branches
■ Cell
■ Structure of a Cell
■ Kingdom Classification
■ Classification of Plant Kingdom
■ Parts of a Plant
■ Modifications of Plants
■ Plant Nutrition
■ Plant Tissues
■ Plant Movements
■ Living Medium of Plants
■ Plant Hormones
■ Plant Process
■ Pollination and Seed Dispersal
■ The Kingdom of Animals
■ Physiology and Health
■ Human Body Digestive System
■ Respiratory System
■ Circulatory System
■ Excretory System
■ Nervous System
■ Endocrine System
■ Reproductive System
■ Skeletal System
■ Genetics
■ Ecology
■ Evolution
■ Pollution
■ Agriculture
■ Food, Health and Nutrition
Chemicals in Food
1. Artificial Sweetening Agents
Saccharin is the first artificial sweetener. Saccharin is an artificial sweetener that is approximately 550 times sweeter than sugar cane. Ortho Sulphobenzimide is the other name of Saccharin. It is a synthetic substance used in food and beverages in place of sugar. Artificial sweeteners are sweeter and have fewer calories than sucrose. Sucralose is an artificial sweetener that is a trichloro variant of sucrose. Aspartame is an artificial sweetener that is 100 times sweeter than sugar cane and about 200 times as sweet as sugar. A number of countries including USA and UK have approved its use. Alitame is a more stable artificial sweetener than Aspartame. Alitame is 2000 times sweeter than sucrose.
2. Food Preservatives
Food Preservatives are those that prevent food from spoiling due to the growth of microorganisms. Examples of Food Preservatives are Salt, Sugar, Vegetable Oils, Sodium Benzoate etc.
3. Food Additives
It is any chemical that food manufacturers intentionally add to one of their products. Some additives increase a food's nutritional value. Others improve the colour, flavour or texture of foods. Still others keep foods from spoiling. Common food additives include iodine, put into salt to prevent goitre and baking powder added to dough to make it rise. Some food additives come from other foods. Scientists also create many synthetic additives in the laboratory. Some people consider food additives dangerous to their health. But many of these chemicals occur naturally in foods that people have eaten for centuries.
4. Antioxidants in Food
These help to preserve food by reducing the action of oxygen on it. Example - Butylated Hydroxytoluene (BHT), Butylated hydroxyanisole (BHA).
Chemicals used in food and their uses
1. Tartrazine - to give yellow colour
2. Erythrosine - to give red colour
3. Phosphoric Acid - to get a sour taste in artificial drinks
4. Allyl Hexanoate - to get pineapple smell
Artificial Sweetening Agents
Artificial sweetening agents are chemicals that sweeten food. Unlike natural sweeteners, they do not increase the body's calorie intake. C. Fahlberg, a student of American scientist Ira Remsen, found the first artificial sweetener in his lab. After creating a commercial synthesis, he filed for a patent in 1885 and called the product saccharin. Compared to sucrose, artificial sweeteners are sweeter and have fewer calories. People with diabetes and those on weight loss diets frequently utilize artificial sweeteners. According to experiments, those who consume significant amounts of artificial sweetness may be endangering their health. The United States and the United Kingdom banned the artificial sweetener Cyclamates in 1970. Examples of artificial sweeteners include alitame, sucrose, aspartame, and saccharin. The following is an explanation of them.
1. Saccharin
Saccharin is a synthetic sweetner. Petroleum and toluene are used to make it. It has no food value and no carbohydrates, yet it is roughly 300 times sweeter than table sugar. Additionally, saccharin leaves a bitter aftertaste. People with diabetes and those on weight loss diets frequently use saccharin as a substitute for sugar. It is manufactured as a liquid, powder, or small tablets. Saccharin is used by manufacturers to make low-calorie soft beverages, sugar-free chewing gum, puddings, jams, jellies, and salad dressings. According to tests, saccharin may occasionally result in cancer. Johns Hopkins University scientist Constantin Fahlberg made the discovery of saccharin in 1879. From 1900 onwards, it has been offered for sale commercially.
2. Aspartame
Aspartame was discovered in 1879. Aspartyl phenylalanine-1-methyl ester is the chemical name of this dipeptide methyl ester. It is frequently used in many different foods and as a tabletop sweetener. It loses its sweetness and breaks down into amino acids when heated, therefore baked foods cannot use it. It is exclusively utilized in cold foods and soft drinks because it becomes unstable at cooking temperatures. Aspartame is an artificial sweetener that is 100 times sweeter than sugar cane and about 200 times as sweet as sugar. A number of countries including USA and UK have approved its use. Diabetics Patients can use Aspartame.
3. Sucralose
Sucralose is an artificial sweetener that is a trichloro variant of sucrose. Sucralose is a better alternative to sugar and an artificial sweetener. Since the body cannot break down most of the ingested sucralose, it is noncaloric in nature.
4. Alitame
Alitame is a more stable artificial sweetener than Aspartame. Alitame is 2000 times sweeter than sucrose.
Nutrition - Definition, Types, Examples
The process by which organisms take in and utilize food is called nutrition. The study of nutrition is called nutritional science or trophology. Essential Nutrients are elements in food that are essential for health and maintaining body functions. These essential nutrients are divided into macronutrients (carbohydrate, protein and fat), micronutrients (vitamin and mineral), and water. A balanced diet is one that includes all the nutrients the body needs in the proper amounts for growth and maintenance. Normally a balanced diet should provide about 2400 calories per day for a normal adult. Milk is an example for balanced diet. The headquarters of National Institute of Nutrition is located at Hyderabad.
Types of Essential Nutrients
1. Carbohydrate
It is one of the three main classes of nutrients essential to the body. The others are fats and proteins. Carbohydrates include all sugars and starches and also some other substances such as cellulose and glycogen. They are the main source of energy for animals and plants. They are used by the body as fuel. Foods high in carbohydrate content include bananas, bread, potatoes and rice. Carbohydrates consist of carbon, oxygen and hydrogen atoms arranged in 'building blocks' called Saccharides, Glycogen, or animal starch, is the chief form of stored carbohydrate in animals.
2. Protein
Protein is one of the three main classes of food that essential to the body. The others are carbohydrates and fats. Proteins exist in every cell and are essential to plant and animal life. Plants build proteins from materials in the air and the soil. Human beings and animals obtain proteins from the foods they eat. Foods that are high in protein content include cheese, eggs, fish, meat and milk. In 1838, a Dutch chemist Gerardus Johannes Mulder introduced the word 'protein'. In 1907 Emil Hermann Fischer, a German chemist built a protein molecule made up of 18 amino acid.
3. Fat
Fats are insoluble in water but soluble in organic solvents. Major sources of fats are butter, ghee, oils, ground nuts, almonds etc. One gram of fat yields 9.3 calories of energy. Fat is any of a group of chemical compounds found in both animals and plants. Carbon, hydrogen, and oxygen make up fats. They belong to one of the three major dietary groups that the body needs. The others are carbohydrates and proteins. An animal fat or plant that is liquid at room temperature is called an oil. Alcohols, chloroform, ether, and petrol can dissolve fats and oils, but water cannot dissolve them. Some fats are hard, while some other fats are soft. Fats in butter, lard and margarine are soft at room temperature.
4. Vitamin
The Englishman Sir Frederick Gowland Hopkins is credited with the discovery of idea of vitamin concept. He discovered in 1906 that food contains important elements called vitamins other than carbohydrates, minerals, fats, proteins, and water. Hopkins shared the 1929 Nobel Prize in medicine and physiology for his discovery of growth stimulating vitamins. Polish born Casimir Funk (US) made great advances in 1912 when he hypothesized that certain diseases such as beriberi, scurvy, pellagra and rickets are caused by deficiencies of nutrients he called 'vitamins'.
5. Mineral
Mineral is a homogenenous inorganic material needed for body. These control the metabolism of body. The important minerals in our body are sodium, potassium, calcium, phosphorous, iron, iodine, magnesium, zinc, copper and cobalt.
6. Water
Human get water by drinking. Water is the important component of our body. 65 to 75 percent weight of the body is water. Although humans have used water since the dawn of civilization, its exact chemical composition was not known until 1784, when the English chemist Henry Cavendish discovered that it consisted of hydrogen and oxygen. Later he proved the exact ratio of the two gases.
Carbohydrates - Definition, Type, Examples
Carbohydrates are organic compounds containing carbon, hydrogen and oxygen which constitute sugars (starch, cellulose, glucose etc) and supply calories for body activity. One gram of carbohydrate provides 4.2 calories of energy. The ratio of hydrogen to oxygen in the Carbohydrate is 2:1. The sources of carbohydrates are rice, wheat, honey, sugar, potato, carrot, banana, bread etc. Deficiency of carbohydrates causes weight loss and weakness. Based on the number of sugar units they can be classified into, Monosaccharides, Disaccharides, Oligosaccharides and Polysaccharides. Starch, Sugar, Cellulose, Glucose, Inulin, Glycogen and Chitin are various types of Carbohydrates.
Types of Carbohydrates
1. Starch
Glucose is a basic sugar that plants use to make starch. The most significant dietary supply for higher animals is a polysaccharide reserve found in plants. Grains and tubers contain starch in the form of starch. Iodine Test is the test related to finding the presence of starch. When starch reacts with iodine solution, it produces a deep blue color.
2. Sugars
Since sugars are in their most basic form, they are also known as simple carbohydrates. Sugars are classified into monosaccharides, disaccharides and polysaccharides.
i. Monosaccharides - Also called as simple sugars. Examples of monosaccharides include glucose, fructose, and galactose.
ii. Disaccharides - Also called as double sugars. Examples of disaccharides include Sucrose (Table Sugar), Lactose and Maltose.
iii. Polysaccharides - Also called as complex carbohydrates, which are chains of glucose molecules. Examples of polysaccharides include starch and glycogen.
3. Cellulose
The most abundant organic material in plants is cellulose, which is found only in plants. It is the main component of the cell wall of plants. Cellulose is totally absent in animal cell. Cellulose, though not digested has great importance in human nutrition. It is major constituent of fibre.
4. Glucose
Glucose is a type of sugar also called as grape sugar. Glucose is a product of photosynthesis in green plants and is the chief source of energy for most living organisms. The presence of glucose in any subsance can be identified using benedict test. If sugar is present in the Benedict test, the result is a brick red color.
5. Inulin
Inulin not a sugar itself, and is often used as a sugar substitute due to its prebiotic properties and potential health benefits.
6. Glycogen
Glycogon is the carbohydrate reserve in animal hence it is often reffered to as animal starch. It is present in high concentration in liver, followed by muscle, brain etc. Glycogen is also found in plants that do not possess chlorophyll.
7. Chitin
Chitin is a structural polysaccharide found in exoskeleton of some invertebrates. eg: insects and crustaceans.
Sugars - Definition, Types, Examples
Sugar is a food widely used as a sweetener. People sprinkle sugar on such foods as grapefruit and cereal to improve their taste. All green plants produce sugar. But most sugar that people use comes from sugar cane and sugar beets, which produce a sugar called sucrose. Other sources of sugar include cornstarch, milk, maple syrup and honey. Sugars are also referred to as simple carbohydrates because they are in their most basic form. Monosaccharides, disaccharides and polysaccharides are three types.
1. Monosaccharides
Monosaccharides are also called as simple sugars. Examples of monosaccharides include glucose, fructose, and galactose.
i. Glucose
Glucose is a type of sugar. Glucose is a product of photosynthesis. Honey and fruits like grapes and figs contain a lot of glucose. Pure glucose is a white crystal. It is about three fourths as sweet as sucrose. Its chemical formula is C6H12O6. Glucose belongs to a class of foods called carbohydrates. It is the most numerous of the monosaccharides, or simplest carbohydrates. Because of its simple chemical structure, glucose can be absorbed directly into the blood from the intestine. Most complex carbohydrates, including sucrose and starch, must be broken down into monosaccharides before being absorbed into the blood. Glucose is made commercially from starch.
ii. Fructose
Fructose is the sweetest natural sugar. It is a sugar produced by nearly all fruits and by many vegetables. Fructose also known as fruit sugar is nearly twice as sweet as sucrose. Fructose is used to sweeten such food products as diet foods, gelatin desserts, jams, jellies, soft drinks and syrups. It is the chief sweetener in honey. Foods that contain fructose taste as sweet as similar foods made with sucrose, but they may have fewer calories, fructose gives ice cream and sweets a smooth texture. It also absorbs moisture readily and so helps to keep baked goods from becoming stable. Fructose is produced commercially as a liquid, powder or tablet. Food processors use fructose primarily in the form of syrup prepared from maize.
iii. Galactose
Galactose is a simple sugar that is as sweet as glucose, and about 65% as sweet as sucrose. It is usually found in nature combined with other sugars.
2. Disaccharides
Disaccharides are also called as double sugars. Examples of disaccharides include Sucrose (Table Sugar), Lactose and Maltose.
i. Sucrose (Table Sugar)
Sucrose, generally known as cane sugar, is the primary carbohydrate produced during photosynthesis. It is carried into plants' storage organs.
ii. Lactose
Lactose is most generally referred to as milk sugar. Lactose of milk is the most important carbohydrate in the nutrition of young mammals.
iii. Maltose
Maltose is the chemical term for malt sugar. The formation of maltose is the first step in the digestion of starchy foods. The enzyme ptyalin in saliva changes starch into maltose. Other enzymes split the maltose into glucose. Commercially, the enzyme diastase in malt changes starch into maltose. Fermentation changes maltose into alcohol. This is recovered by distillation. Maltose is used for sweetening some foods.
3. Polysaccharides
Longer chains of monosaccharides and disaccharides are not regarded as sugars and are called polysaccharides. Polysaccharides are also called as complex carbohydrates, which are chains of glucose molecules. Examples of polysaccharides include starch and glycogen.
i. Starch
Glucose is a basic sugar that plants use to make starch. The most important food source for higher animals is a polysaccharide reserve found in plants. Grains and tubers both contain starch..
ii. Glycogen
Glycogen is a tasteless, odourless white powder. Glycogen is a carbohydrate. It is made up of basic sugar units called glucose that are linked together in branching chains. Glycogen is produced and stored in the liver and muscles. It is composed of excess starch and sugars in the body. These are first converted to glucose. Excess glucose is then changed into glycogen. Glycogen is often called animal starch. It is a reserve food and is easily reconverted to glucose.
Proteins - Definition, Types, Examples
Proteins are highly complex nitrogenous compound found in all living organisms. They form the structural and functional basis of life. Proteins are necessary for the growth and repair of bodily tissues. They also offer energy when calories are low. Protein is composed of carbon, hydrogen, nitrogen, and oxygen. Proteins are incredibly large molecules composed of monomers known as amino acids. Amino acids are the building blocks of proteins. There are twenty standard amino acids. Protein-rich foods include milk, fish, meat, eggs, nuts and dal. Soyabean seeds posses highest percentage of proteins (30-35%). Protein deficiency causes kwashiorkar - skin cracks and become scaly, abdomen swells, hair become reddish. Deficiency of protein and carbohydrate results in Marasmus.
Types of Proteins
There are seven types of proteins. They are antibodies, contractile proteins, enzymatic proteins, hormonal proteins, structural proteins, storage proteins and transport proteins
1. Antibodies
A protein produced by animal plasma cells as a result of the presence of an antigen. Antibody production is maintained by contact with the antigen; subsequent exposure to the antigen produces a greater antibody responses which provides the basis of immunity. Antibodies contribute to the body's resistance to infection and are responsible for the rejection of foreign tissue or organ transplants. Antibodies are an example of proteins that attach to one specific type of molecule.
2. Contractile Proteins
Contractile Proteins are responsible for the function of muscle contraction and movement. Cell cytoplasm is a colloidal network made up of contractile proteins.
3. Enzymatic Proteins
The most important proteins are the enzymes. Protein present in hair, skin and nails is keratin. Protein present in silk is fibroin. The first pure enzyme to be crystallized was Jackbean urease, prepared by James Batcheller Sumner (US) in 1926. Sumner's work proved that enzymes are proteins and that proteins can act catalytically. Enzymatic proteins are enzymes that speed up chemical reactions in our body.
4. Hormonal Proteins
Hormonal Proteins are messenger proteins that assist coordinate various body functions. Growth factors, Testosterone and Cortisol are examples of Hormonal Proteins.
5. Structural Proteins
Structural Proteins provide support in our body. They maintains and protects the structure of the our body. For example, the proteins in our connective tissues, such as collagen and elastin.
6. Storage Proteins
Storage Proteins store metal ions such as iron in our body. Casein is a storage protein found in egg whites. Examples of other storage proteins include Ferritin, which is a storage protein that stores iron.
7. Transport Proteins
Transport Proteins are carrier proteins that carry molecules from one place to another in the body. Hemoglobin and Cytochromes are examples of Transport proteins. The respiratory protein hemoglobin transports oxygen from the lung to body organs and tissues. Cytochromes functions as an electron carrier protein.
Vitamins - Types, Food Sources, Deficiency Diseases
Unlike carbohydrates, proteins and fats, vitamins do not provide calories, but they help the body to use the energy from food. Most vitamins cannot be made in our body. So they must be acquired from food. Vitamins A, D, E, K are fat soluble whereas Vitamin B complex and C are water soluble. Milk is a rich source of all vitamins except Vitamin C. Overdose of water soluble vitamin does not cause any harm but accumulation of fat soluble vitamin can be toxic. It can lead to hypervitaminosis. Even though the amount of vitamins required are small compared to other nutrients, it is very necessary. Otherwise several deficiency diseases are caused in the body. Vitamin D (in skin) and Vitamin K (in liver) can be synthesized by our body.
Different Types of Vitamins
1. Vitamin A
Vitamin A also called as Retinol is a fat soluble vitamin, needed for healthy vision, bone growth, reproduction and the immune system. The best food source for this vitamin is carrots and yellow and green vegetables. Other sources include butter, milk, fish, soya milk etc. The deficiency of Vitamin A causes Xerophthalmia (drying of cornea and ulceration), Night blindness (inability to see in the dark) and Keratinization of epithelium (dry skin and hair). Elmer Vernon McCollum (US) and Marguerite Davis (US) found vitamin A in butter and egg yolk in 1913.
2. Vitamin B
Edward Vedder (US) and Robert Williams (US) are given credit for being the first to detect water-soluble vitamin B in 1912 as an antineuritic substance effective in curing pigeons of neuritis, a disease similar to that of beri-beri in humans. Three years after the discovery Elmer Vernon McCollum (US) and Marguerite Davis (US) labelled it 'water-soluble B', which british biochemist Jack Cecil Drummond changed to 'Vitamin B' in 1920. Vitamin B complex includes B1, B2, B3, B5, B6, B7, B9 and B12.
3. Vitamin B1
Vitamin B1 also called as Thiamine, is a water soluble vitamin helps to break down carbohydrates, fats and alcohol. The best food source for this vitamin is whole grains, yeast, egg, potatoes, pork, nuts etc. The deficiency of Vitamin B1 causes beri-beri (partial paralysis of skeletal muscles and digestive disturbances).
4. Vitamin B2
Vitamin B2 also called as Riboflavin, is a water soluble vitamin needed to extract energy from fat, protein, carbohydrate in food. Riboflavin is abundantly present in milk. So it is also known as lactoflavin. The best food source is cereals, legumes, milk, egg, meat, fish, spinach etc. The deficiency is that it is characterized by corneal ulceration and cracking of skin (especially around the lips).
5. Vitamin B3
Vitamin B3 also called as Niacin, is a water soluble vitamin involved in fat metabolism. The best food source are lean meat, milk, eggs, nuts, whole grains etc. The deficiency diseases are Pellagra (characterized by dermatitis, skin inflammation), diarrhoea and dementia (loss of intellectual function).
6. Vitamin B5
Vitamin B5 also called as pantothenic acid, is a water soluble vitamin, supports blood cell production and the conversion of food you eat into energy. The best food source are meat, milk, eggs, nuts, whole grains, and some vegetables. The deficiency diseases are fatigue, irritability, and digestive problems.
6. Vitamin B6
Vitamin B6 also called as Pyridoxine, is a water soluble vitamin. The best food source are fish, pork, eggs, spinach, cheese, cereals and bananas. The deficiency disease is Epileptiform seizures observed in children. Its symptoms include dermatitis of eyes, nose and mouth; retarded growth.
7. Vitamin B7
Vitamin B7 also called as Biotin, is a water soluble vitamin. The best food source are meat, eggs, nuts, seeds, legumes, fruits, cereals and vegetables. The deficiency diseases causes the symptoms of hair loss, brittle nails, skin rashes, and neurological issues.
8. Vitamin B9
Vitamin B9 also called as Folic Acid, is a water soluble vitamin. It is essential for the normal formation of the red blood cells, protein metabolism, growth and cell division. The best food source are yeast, green leafy vegetables, milk, cereals and nuts. The deficiency disease is megaloblastic anemia (production of abnormally large red blood cells).
9. Vitamin B12
Vitamin B12 also called as Cyanocobalamin, is a water soluble vitamin, involved in the production of red blood cells, in cell metabolism and in nerve function. The best food source are meat, eggs, milk and cheese. It is the only vitamin containing cobalt, which is absent in vegetables. The deficiency diseases are pernicious anemia and neuro-psychiatric abnormalities (memory loss, mood and personality changes).
10. Vitamin C
Vitamin C also called as Ascorbic acid, is a water soluble vitamin. It is easily destroyed by heat and light. So vitamin C rich food should be stored in cool, dark place and prepared and cooked as quickly as possible. It is essential for disease resistance and wound healing. The best food source are citrus fruits, tomatoes, cabbage, spinach, potatoes, broccoli etc. The deficiency disease is scurvy and its symptoms are swollen gums, teeth loss and bleeding gums.
11. Vitamin D
Vitamin D also called as Calciferol, is a fat soluble vitamin. It controls the absorption of calcium and phosphorous, which are essential for bone growth and development. The best food source are fish liver oils, egg yolk, milk, butter. Also synthesized in the human body by the skin under the influence of sunlight. The deficiency diseases are rickets (in infants), bones become soft (deformed) and Osteomalacia (demineralization of bones).
12. Vitamin E
Vitamin E also called as Tocopherol, is a fat soluble vitamin. It protects red blood cells and is important in reproduction. The best food sources are wheat germ, fresh nuts, seed oils, green leafy vegetables, avocados etc. Its deficiency not reported in humans, occurring only in premature babies (infertility).
13. Vitamin K
Vitamin K also called as Phylloquinones, is a fat soluble vitamin. It is involved in blood clotting. The best food sources are liver, spinach, cauliflower, green tomatoes, pork etc. Its deficiency disease is Hemorrhage (Subcutaneous and intramuscular bleedings due to delayed clotting time).
