Food Chemistry

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What is Food Chemistry?

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Food is one of the basic needs of life, without which one cannot survive for more than a few weeks. Have you ever wondered, what is our food made of and how does it undergo changes?

Food chemistry is the study of chemical composition and the interactions between the components present in food. Food chemists mainly focus on how the plant and animal-based foods are prepared, processed and distributed. Food also undergoes changes because of the elements present in it. Food chemistry helps us to find out what causes these changes and what are the primary components that make up our food.

For example, the wine and beer industries use the process of fermentation of grapes and barley by microorganisms to prepare these alcoholic beverages. In the same manner, the conversion of milk into curd by lactobacillus bacteria is an example of a chemical change that takes place in milk due to the formation of lactic acid from lactose. 

The concepts of food chemistry have been borrowed from chemical bonds and interactions, biopolymer science, colloidal interactions, chemical thermodynamics, etc. 

Components of Food

The main components of food are as follows: 

  • Carbohydrates

Carbohydrates are a group of compounds that are found in plants and animals. They have the general or empirical formula as Cm(H2O)n. Since they essentially contain carbon and water, they are referred to as hydrates of carbon or carbohydrates. Carbohydrates are energy giving foods. They are digested, absorbed and assimilated by the body after being changed into simpler substances such as glucose, which is then oxidized to release energy. Simple carbohydrates include sugars and complex carbohydrates include starch and fibre. A monosaccharide is the simplest carbohydrate. Glucose and fructose are monosaccharides. 

Grains such as wheat and rice, fruits such as bananas, bread, etc. are important sources of carbohydrates. 

  • Proteins

Proteins are complex macromolecules that play an important role in the functioning of cells. They are primarily composed of nitrogen, hydrogen, oxygen and carbon. They may also contain zinc, phosphorus and copper in small quantities. Proteins are called bodybuilding foods, as they are essential for the growth and repair of the body. Proteins can be obtained from both plants and animals. Some plant sources of proteins include legumes, grains, nuts whereas the animal sources include meat, milk and eggs. 

  • Lipids

Lipids are molecules that are non-polar in nature and are relatively insoluble in water. They include fatty acids, phospholipids, glycolipids, terpenoids etc. They may have a linear structure or a ring-like structure. They can be either aliphatic or aromatic. Lipids exhibit some polarity but a major part of their molecule is hydrophobic or nonpolar. The food sources of lipids include grains such as soybean and corn. They are also found in many animal products such as cheese, meat, milk etc.  

  • Water

Water is an important component of food and it can have a composition ranging anywhere between 50 to 95%. The presence of water in food is one of the main reasons for higher bacterial growth which can lead to quick spoilage of food, if not preserved properly. Reducing the amount of water present in food is one of the most important ways to enhance the shelf life of food products.

  • Vitamins and Minerals

Vitamins and minerals are the nutrients that are required by the body in small amounts. They are also called protective foods because they help the body to fight against diseases and infections. Vitamins can be classified as water-soluble or fat-soluble. If sufficient vitamins are not included in the diet, then their shortage can lead to various deficiency diseases, such as anaemia, beriberi, scurvy, etc. Minerals such as potassium, magnesium, and calcium are also required by the body in tiny amounts. Some of them are naturally found in food, but they can also be taken as supplements. 

  • Colours, Flavours and Additives

Artificial flavours, colours and additives can be added to food to improve the smell, taste and for the purposes of processing and preserving. 

  • Enzymes

Enzymes are biological catalysts that help in speeding up a biochemical reaction. They can complete a chemical reaction in a lesser amount of time with lesser expense of energy. Enzymes are used in many food processes, such as brewing, fermentation, baking etc. 

FAQ (Frequently Asked Questions)

1. What happens when baking soda is heated?

Baking soda is a commonly used substance in the kitchen. It is a chemical compound, which is also known as sodium bicarbonate. As we know, when food products are subjected to various processes, such as heating, they may undergo chemical changes. When baking soda is heated, it releases carbon dioxide gas. 

This principle is mainly used in the baking industry. Baking soda is added to the dough. As it gets heated, it decomposes to form bubbles of carbon dioxide gas, which try to escape upwards, making the dough fluffy and spongy. 

2 NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g)

2. What are some examples of food chemical changes around us?

Chemical changes are always characterized by the formation of a new substance. Certain chemical reactions are highly noticeable, but the food chemical changes taking place around us are quite subtle. Some examples of food chemical changes around us are as follows:

  • Baking of a cake: The cake rises and becomes spongy due to the bubbles of carbon dioxide gas trying to escape from the batter after the decomposition of baking soda. 

  • Caramelization: In the process of caramelization, sugar decomposes to form a specific taste and aroma. 

  • Fermentation: It is the process in which a living organism will convert a carbohydrate, such as starch or sugar into alcohol or an acid. The batter which is used to prepare dosa and idli is often fermented for a long period of time. Even in the case of bread, yeast is added to the dough. The yeast decomposes the starch to form sugars. The sugar then metabolizes to form carbon dioxide and alcohol. It is the carbon dioxide that makes the bread rise. Bacteria ferment the lactose in milk into lactic acid and change it to curd.