Nutritional components of food: refers to the components in food that have nutritional significance to human body.

Mainly protein, fat, carbohydrates, vitamins, minerals (also known as inorganic salts) and water. Among them, protein, fat and carbohydrate are called the three major nutrients. They are the main ingredients in animal and plant food and can provide energy for the body. Inorganic salts and vitamins can't provide heat for human beings, but they are important components of many enzymes and physiologically active substances in human body. Water is an important substance to maintain human survival.

Whether the intake of food nutrients is reasonable or not is directly related to human health, but no natural food can supply all the nutrients needed by human body. Therefore, it is necessary to analyze the nutritional components of food, grasp the quality and quantity of nutritional substances in food, guide people to have reasonable nutrition and diet, detect the nutritional components in the process of food production, processing, transportation, storage and sales, and timely understand the changes in food quality, so as to provide reliable basis for the research and development of new food resources and new products.

Section 1 Determination of Moisture in Food

Water is a natural component of food and an indispensable component in animals and plants, which has extremely important physiological functions. For example, water is a good solvent for nutrients and their metabolites in the body, and it is also the medium for various chemical reactions in the body. It can help the absorption of nutrients and the transportation and excretion of metabolites, and it also plays an important role in regulating body temperature, lubricating joints and muscles and reducing friction.