Water activity (also called "water activity") is defined as the ratio of the vapor pressure of a given food to the vapor pressure of pure water at the same temperature. It is generally referred to as aw from the English language Water activity, aw ). The water activity is a parameter closely linked to the humidity of the food, which allows determining its conservation capacity, microbial propagation, etc. The water activity of a food can be reduced by increasing the concentration of solutes in the aqueous phase of the food by removing the water (lyophilization) or by adding new solutes. Water activity along with temperature, pH and oxygen are the factors that most influence the stability of food products.

Formal Definition A more formal definition of water activity, represented by aw:


There are several factors that control the water activity of a system. The colligative effects of dissolved species (such as salt or sugar) on dipolar, ionic, or hydrogen bond interaction with water molecules. The capillarity effects when the water vapor over the meniscus is less than in pure water due to hydrogen bonding interactions between the water molecules. Surface interactions interact directly with the bonds of dissolved or suspended substances (such as starch or proteins) through dipolar forces of ionic bonds (H3O++ or OH-), Van der Waals forces (hydrophobic bonds) and hydrogen bonds. The combination of these three factors in food products reduces the energy of the water and also reduces the relative humidity compared to pure water. These factors can be grouped into two broad categories: osmosis and matrix effects.

We speak of an aqueous solution whenever the solvent (or the majority solvent, in the case of a mixture of solvents) is water. Water as a solvent is very polar and forms very strong hydrogen bonds.

Aqueous solutions are of great importance in biology, from basic science laboratories to the chemistry of life, including industrial chemistry. Because of the vast number and variety of substances that are soluble in water, water is sometimes called the solvent of the millennium.

Ionic compounds, such as sodium chloride, are the most soluble in water, while covalent compounds are usually just as poorly soluble as insoluble metals.

There is also talk of aqueous solution when the abundant Saliva that comes out of the mouth and flows through the lips. of non-terrestrial beings try to attack you and therefore kill


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