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Food Chemistry

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What is Food Chemistry?

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. 

FAQs on Food Chemistry

1. What is Food Chemistry?

Food Chemistry is the branch of chemistry that studies the chemical processes and interactions of all biological and non-biological components of foods. It covers the chemical composition, structure, and properties of food components like carbohydrates, lipids, proteins, vitamins, minerals, and additives, and the chemical changes they undergo during processing and storage.

2. What are food preservatives and why are they important?

Food preservatives are chemical substances added to food to prevent or delay its spoilage due to microbial growth (like bacteria or fungi). They are important because they increase the shelf-life of food, keeping it safe and fresh for longer periods. Common examples include salt, sugar, vinegar, and chemical preservatives like sodium benzoate.

3. What are some common chemical changes that happen when we cook food?

Cooking involves several chemical changes that alter the taste, texture, and appearance of food. Some common examples include:

  • Caramelization: The browning of sugar when heated, which creates a sweet, nutty flavour.
  • Maillard Reaction: A reaction between amino acids and reducing sugars that gives browned food its distinctive flavour, like in toasted bread or seared meat.
  • Leavening: The release of gases, like carbon dioxide from baking soda, which makes cakes and bread rise and become fluffy.

4. What are artificial sweetening agents? Give an example.

Artificial sweetening agents are chemical compounds that provide a sweet taste like sugar but contain significantly fewer calories. They are often used in food products for people who need to control their calorie or sugar intake. A common example is Aspartame, which is about 200 times sweeter than regular table sugar.

5. How do antioxidants work to protect food?

Antioxidants are substances that prevent or slow down damage to food caused by oxidation. Oxygen in the air can react with fats and oils in food, making them go rancid. Antioxidants work by sacrificing themselves and reacting with the oxygen first, thereby protecting the food's nutrients, flavour, and colour. Common examples used in food are BHA (Butylated hydroxyanisole) and BHT (Butylated hydroxytoluene).

6. Why are artificial sweeteners often recommended for diabetic patients?

Artificial sweeteners are recommended for diabetic patients because they are either not metabolised by the body or are metabolised differently from regular sugar (sucrose). This means they do not cause a rapid increase in blood glucose levels. This allows diabetic individuals to enjoy sweet-tasting foods without negatively impacting their blood sugar control. Examples include Saccharin and Alitame.

7. What is the main difference between natural and artificial food colouring?

The main difference lies in their origin. Natural food colours are derived from plant, animal, or mineral sources, such as beet juice (betanin) or turmeric (curcumin). Artificial food colours, on the other hand, are synthetic chemicals created in a lab. While natural colours are often perceived as healthier, artificial colours are typically more stable, vibrant, and less expensive to produce.