Caloric Value of Proteins

Introduction

The calorie is an energy unit defined as the amount of heat required to raise the temperature of one kilogram of water by one degree celsius (or kelvin).

Two primary definitions of calorie are widely used. The amount of heat required to raise the temperature of one gram of water by one degree celsius is known as a tiny calorie or gram calorie (commonly abbreviated as cal) (or kelvin).  A large calorie, also known as a food calorie or a kilocalorie (cal, calorie or kcal), is the amount of heat required to create the same increase in one kilogram of water.  As a result, one kilocalorie (kcal) equals 1000 calories (cal). 

Calorie is a term used in food science to refer to a huge calorie. The nutritional energy value in (kilo or big) calories per serving or per weight is required on the labels of industrialised food products in most countries.

Calorie is directly related to the metric system and thus the SI system. Since the establishment of the SI system, it has been considered outmoded by the scientific community, but it is still in use. The joule is the SI unit of energy. A calorie is equal to 4.184 J, while a calorie (kilocalorie) is equal to 4184 J.

The Calorific Value of Proteins

To calculate the average daily intake of proteins, the ratio of the 1 gram of the protein is used for every kilogram of the weight of the person. If a person is physically active, their body’s protein requirements would be more. According to a study, the protein levels that are required for varying activities are as follows:

• For minimal activity levels, 1 g of protein is required for every one kg of body weight.
• For moderate activity levels, 1.3 g of protein is required for every one kg of the body weight.
• For intense activity levels, 1.6 g of protein is required for one every kg of the body weight.

Maintenance of Optimum Calorific Value of Proteins

Usually, people can only consume 2 g of caloric value of proteins per one kg of their body weight everyday without having any significant side effects. This level can be increased up to 3.5 grams for some athletes. The production of increased energy from proteins can cause dehydration, irritability, nausea, headache, diarrhoea, unexplained exhaustion and intestinal discomfort.

Food value is measured in calories per gram. A calorie is the amount of heat necessary to raise the temperature of 1 gram of water by 10C (particularly from 150 C to 160 C) 1000 calories are equal to a large calorie (written with a capital C) or kilocalorie. The term kilocalorie or calorie (abbreviated as cal) is used when discussing energy metabolism.

To measure the amount of energy contained in various diets, a known weight sample is placed in a bomb calorimeter, which is a metabolic chamber with an apparatus for producing electric sparks. The bomb calorimeter is encased in a known amount of water whose temperature is recorded. The meal is ignited when a spark is formed. The heat produced by the food combustion helps in raising the temperature of the surrounding water. The temperature of the water is measured once more and a rise in its temperature is discovered. The total heat released in this process can simply be calculated from the rise in water temperature.

Conclusion

The gross calorific value of a gram of food is the amount of heat energy emitted after combustion. (It is measured with a bomb calorimeter.) Carbohydrates, proteins and lipids have calorific values of 4.1, 5.65 and 9.45 kcal/g respectively.

The quantity of energy created by the oxidation of 1 gram of dietary material in the body is referred to as physiologic value. Carbohydrates, proteins and lipids have physiologic values of 4.0 kcal/g, 4.0 kcal/g and 9.0 kcal/g, respectively. It has a lower calorific value than the gross calorific value.