Nutrition Meets Food Science

Eggs to Omelette

People love to eat eggs, whether in the morning as breakfast, lunch or dinner. Eggs have been a part of our daily life for thousands of years, obviously, because of their taste. But, apart from taste, there are many health and nutritional benefits of consuming eggs. They are packed with many nutrients required by the human body. People normally consume the eggs of birds.

Types of Eggs: There are different types of eggs like hen eggs, duck eggs, turkey eggs, etc. Hen’s eggs come in both white & brown colours. However, there is hardly any difference in the nutritional content. The only difference is the colour, because of the breed of the chicken.

Egg Size: Depending upon the weight and size of the eggs, they are classified into:

  • Jumbo: more than 70 g
  • Extra-large: 60–70 g
  • Large: 53-59 g
  • Medium: 45-52 g
  • Small: 38-42 g

Nutrition in Egg: Eggs are very nutritious and healthy. An egg contains nutrients such as: (per 100 g raw egg).

Proteins 13 g
Fats 9 g
Carbohydrates Less than 1 gm
Vitamins Vitamins B1, B2, B3, B5, D, A etc.
Minerals Calcium, Phosphorus, Magnesium, etc.

Composition of Egg: An egg consists of a shell, white & yolk. The shell protects the inner content of eggs from any type of contamination. It is composed of calcium carbonate. Egg white contains a protein called albumen. Egg yolk contains fats, a small amount of protein, vitamins, minerals, etc.

Processing of Egg:

Some of the modern plants processing eggs may follow an elaborate process to clean and store eggs under cooler temperatures until they are processed. As soon as the hen lays the egg, they are collected. Hens can lay up to 250-300 eggs per year. It takes 24-26 hours for a hen to produce an egg. The eggs may be fertilised or unfertilised. Only fertilised eggs upon incubation can produce a chick. After the eggs are laid, they are transported to the grading station for further processing steps.

Washing of eggs: After reaching the grading station, eggs are washed. Cleaning eggs is an important step. At the grading station, the eggs are washed in a sanitizing solution with a brush revolving around the eggs to remove any dust and dirt present on the outer shell.

Grading of Eggs: Grading is a process of sorting eggs based on the condition and quality of eggs. The eggs are graded as per the USDA system into three categories- Grade AA, Grade A and Grade B. While grading eggs the graders look for the interior as well as the exterior quality. Agmark in India has developed grades for eggs, which are even more elaborate based on the size of the eggs and the quality of white and yolk.

  • Exterior Quality: Eggs should be clean, without any cracks, should be oval and should not contain any foreign particles.
  • Interior Quality: Interior quality is determined by a method called Candling. In this method, a bright light is used to evaluate the internal quality of the egg like the condition of the egg yolk & the egg white. Egg yolks must have a strong outline with no blood spots or embryo development, while egg white must be clear and thick.

Packaging: Packaging is a very important step in the entire process, as eggs are very delicate, they must be handled & packed with extreme care. Packaging protects the eggs from microorganisms, breakage, loss of moisture, etc. Eggs are often packed to provide cushioning so that eggs do not break while storage & transportation.

Storage: Eggs must be stored properly before transportation. Storing of eggs should be done with proper care so that the quality does not get deteriorated. The eggs must be stored in a clean & dry place. An appropriate temperature should be maintained in the storage room to maintain quality & freshness.

Transportation: Eggs are transported in a vehicle maintained at an appropriate temperature. It should be done with proper care and maintenance.

Processed Products: Eggs are processed to produce various products used in food.

  • Egg powder: Egg powder is a product obtained by drying the egg. Mostly spray drying method is used to make egg powders. Egg powders are used in many recipes and products like cakes, cookies, pancakes, pastries, etc. There are various types of egg powders like whole egg powder, egg white powder, and egg yolk powder.
  • Frozen eggs: In this, the eggs are first deshelled & strained. Salt or sugar is added. It is then pasteurized and frozen at an appropriate temperature.
  • Liquid eggs: In this, eggs are first deshelled. It is then pasteurized and packed.

Functional Properties: Eggs perform various functional properties in food.

  • Emulsification: Egg is used as an emulsifier in many products like salad dressings, sauces & mayonnaise.
  • Coagulation: The egg protein coagulates upon heating. Heating causes the denaturation of proteins present in the egg & forms a gel structure. Thus, eggs can be used as a thickening agent in many food formulations mainly custards, cakes, pie fillings, cream puddings etc.
  • Foaming: Eggs are a good foaming agent. When eggs are beaten, it entraps air forming a foam. This is used to make sponge & fluffy cakes and muffins.

Earlier, many health professionals said that eating eggs have been associated with heart disease due to their cholesterol content. Because, for most people, the amount of cholesterol eaten has only a modest impact on the amount of cholesterol circulating in the blood. For some people, though, blood cholesterol levels rise and fall very strongly concerning the amount of cholesterol eaten.

However, eating one or two eggs a day would not cause any health problems; in fact, it provides valuable nutrients required by the body.

Earlier when one wanted to make an omelette, eggs were needed and these would be broken and immediately omelette would be prepared with some nice garnish and spices. However, now there are many choices. One can purchase egg powder (whole or separate white or yolk), or even frozen or chilled eggs without shells. In India, only egg powder is available but elsewhere liquid and frozen whole eggs or whites are available. These could be bought and stored. Omelette or other egg recipes could be prepared as, and when one wants. No need to crack an egg.

Ms. Samreen Shaikh

Jr. Food Technologist, PFNDAI

Add comment

Follow us

Don't be shy, get in touch. We love meeting interesting people and making new friends.