Bread, beans, milk, popcorn, rice, potatoes, biscuits, chapati, soft drinks, and cherry pie are just a few carbohydrate-rich foods. Carbohydrate-dense meals are an essential component of a healthy diet. Carbohydrates give the body glucose, converting it into energy for biological and physical tasks. Eating carbohydrates from nutritious meals is more important than following a strict diet that restricts or measures the number of grams of carbohydrates consumed.
Carbohydrates
Carbohydrates are substances that contain carbon, hydrogen and oxygen in a ratio of 1:2:1. General formula Cn(H2O)n. These are also defined as polyhydroxy aldehydes or ketones or the compounds that yield such substances on hydrolysis.
Types of carbohydrates
Carbohydrates are among the four major types of biologically necessary organic compounds found in all living creatures, including lipids, proteins, and nucleic acids. It is a molecule made up of carbon, hydrogen, and oxygen atoms, with a 2:1 hydrogen-oxygen atom ratio in most cases.
Carbohydrates are split into two types: complex and simple.
Complex Carbohydrates
The body needs complex carbohydrates as a source of energy. The behaviour of different carbohydrates during hydrolysis can be used to classify them. They are divided into three categories: monosaccharides, disaccharides and polysaccharides. Disaccharides and polysaccharides are made up of monosaccharides.
Polysaccharides
Polysaccharides, also known as glycans, are giant biological molecules with a high molecular weight. They are nearly pure carbohydrates. Animals and plants build them from simpler monosaccharide molecules by exploiting glycosidic linkages to connect vast numbers of the smaller molecules. Cellulose, starch, glycogen, and chitin are examples of polysaccharides.
Whole-food complex carbohydrates are generally relatively healthy. Whole-grain foods, for example, have a coating of bran and germ that give fibre, vitamin B and E, phytonutrients, and good fats. They may also lower the risk of various chronic illnesses, including type 2 diabetes, cardiovascular disease, and cancer.
Examples of whole grains include brown rice, barley, buckwheat, bulgur wheat, wild rice and oats.
Refined grains are equally complex carbohydrates, but they lack the bran and germ of the grain, and their nutritional value is lower than that of whole-grain diets.
Refined grains include white flour, degermed cornmeal, and white rice.
Complex carbohydrates can also be found in vegetables, legumes, and nuts, all high in nutrients. Leaving the skins on fruits and vegetables before eating them will boost their nutritional content.
Starch
Plants store glucose in the form of starch. Plants produce starch in order to store glucose. For example, starch is present in seeds to provide energy to the seedling, and we consume these seeds in the form of grains, legumes, and seeds. Starch is also stored in roots and tubers, which humans eat as potatoes, sweet potatoes, carrots, beets, and turnips to give stored energy for the plant to develop and reproduce.
We can break down the starch in plant foods into glucose, which provides fuel for our body’s cells. Furthermore, starch from whole plant foods is combined with other beneficial elements.
Glycogen
Glycogen resembles amylopectin in structure, but it is the carbohydrate storage form in animals, including humans. It is stored in the liver and skeletal muscle and is made up of highly branched chains of glucose. Glycogen’s branching form makes it easier to break down fast and release glucose, which can be used as fuel when needed immediately.
Glycogen in the liver is broken down into glucose, released into the bloodstream and utilised by cells throughout the body. Muscle glycogen is a type of energy only used to fuel muscle action.
Fibre
Carbohydrates and other structural elements in plants that are indigestible by human enzymes are referred to as fibre. Plants produce fibre for protection and structural support. Consider the robust stems that help a plant stand upright, the stiff seed husks, and the protective fruit skin. These are a good source of fibre.
Simple Carbohydrates
Carbohydrates, in their most basic form, are simple carbohydrates. Simple carbohydrates are found in soft drinks, candies, cookies, and other sweet treats. White sugar, a processed sugar, is commonly used in these foods. Monosaccharides and oligosaccharides are simple carbohydrates.
Monosaccharides
Monosaccharides have one sugar unit. They play a unique role in digestion and metabolism due to their tiny size. The prefix’ mono-’ means ‘one’.
These are single sugar units whose general formula is Cn(H2O)n where n – 3 to 9 and are commonly called as simple sugars; chemically, all the monosaccharides act as reducing agents. They are classified according to the number of carbon atoms, e.g., trioses (3C), tetroses (4C), pentoses (5C), hexoses (6C) and heptoses (7C). Pentoses and hexoses are the most common ones.
Monosaccharide exists in two forms.
Aldose – A monosaccharide with aldehyde group, e.g., Glyceraldehyde; erythrose, threose xylose, glucose, etc.
Ketose – If the carbonyl group is present internally, the monosaccharide is called ketose, e.g., hydroxy acetone, erythrulose, ribulose, fructose etc.
Structure: Monosaccharides exhibit structural isomerism i.e. same molecular formula but different structural formula. Carbohydrates exist in two following forms.
Monosaccharide derivatives
Glycosides – Medicinally important e.g., streptomyces, cardiac glycosides.
Sugar alcohol – Glycerol for fat synthesis.
Sugar acid – Ascorbic acid – Vitamin C.
Amino sugar – Glucosamine – occurs in chitin fungal wall and hyaluronic acid and in some antibiotics.
Disaccharide
Disaccharides are formed when a condensation process combines two monosaccharides (generally hexoses). The bond formed between two monosaccharides due to condensation is glycosidic and is generally formed between carbon atoms 1 and 4 of the subsequent units.
General formula of disaccharides usually is C12H22O11 (two hexoses). Some disaccharides are reducing in nature and some are non-reducing.
Sucrose (cane sugar) is obtained from sugar cane and sugar beetroots. It is formed by condensing one molecule of glucose and one fructose molecule. Their sweetness index = 100. It is a non-reducing sugar. Sucrose (cane sugar) Glucose + fructose
Maltose (malt sugar) is formed by two sugar units, joined by a glycosidic bond and formed from the digestion of starch by the action of enzyme amylase. It is made up of alpha D-glucose. It is found in germinating seeds. The sugar is present in malt; hence it is known as malt sugar. Sweetness index = 30. Maltose (malt sugar) Glucose + glucose
Lactose (milk sugar) present in milk is formed by a α or β–D-glucose and β galactose, digested by enzyme lactase produced by the small intestine, usually not found in adults. Sweetness index = 16. It is also reducing sugar. Lactose (milk sugar) Glucose + galactose. Lactose, a simple carbohydrate, is found in milk and milk products. Although these foods lack fibre, they are high in protein, calcium, and vitamin D.
Natural sugars also contain simple carbohydrates. Natural sugars can be found in fruits, milk, and vegetables. Honey is also a natural sugar. People consume natural sugar in its purest form. Because they are less (or simpler) complex, simple carbohydrates are easier to handle. They are found in fruit and sugary foods and pretty much anything sweet. The human body may quickly degrade these substances, which may cause some issues.
Simple carbohydrates can be found in various foods that are good for a healthy diet. Fruits and vegetables, for example, include simple carbohydrates but are high in micronutrients such as vitamins and minerals and dietary fibre.
Processed foods and foods with added sugar, like candy, sugary drinks, syrups, and sugary cereals, are examples of simple carbohydrates to avoid. Sugar boosts the calorie level of food while providing no additional nourishment.
Instead of drinking fruit juice, people should attempt to eat whole fruits whenever feasible. Whole fruits are a superior option because they include more nutritional fibre.
There may be occasions when consuming these less healthy, simple carbohydrates is beneficial. Many sports drinks, for example, contain a significant amount of sugar. These drinks are marketed as performance enhancers and rehydration aids by their manufacturers. While sports drinks may help athletes perform better, the effect is likely to be minor. It’s uncertain whether this potential benefit outweighs the adverse health effects of consuming so much extra sugar.
Conclusion
Carbohydrates are the body’s primary source of energy. All forms of carbohydrates can be found in meals. These meals provide health-promoting characteristics and supply energy via glucose. Because complex carbohydrates take longer to digest, they provide a more sustained energy supply than simple carbohydrates. Many healthy foods, such as fruits and milk, contain simple carbohydrates. Refined foods, such as white bread or white rice, may also include more complex carbohydrates than any other food.