What is the Difference Between Free Water and Bound Water?

The main difference between free water and bound water lies in their extraction methods and their binding to other molecules.

• Free water is the water that can be easily extracted from foods or substances by squeezing, cutting, or pressing. It is also known as mobile or unbound water and makes up less than 10% of the total water found in pre-rigor meat. Examples of free water include lemon juice and water in melons.
• Bound water is the water that cannot be easily extracted from foods or substances and is bound to polar and ionic groups in the food. It is also known as immobile or bound water and makes up a very small portion of the total water in muscle, approximately 0.5% of the water in muscle is truly bound. Bound water can be frozen only at a very low temperature that lies below the freezing point of water, exhibits no vapor pressure, and its density is usually greater than that of free water. Examples of bound water include water in cacti plants.

In summary, free water can be easily extracted from foods or substances, while bound water is tightly held within the molecular structure of the material and cannot be easily extracted.

Comparative Table: Free Water vs Bound Water

The main difference between free water and bound water is that free water can be easily extracted from foods through squeezing, cutting, or pressing, while bound water cannot be easily extracted by those methods. Here is a table summarizing the differences between free water and bound water:

Free water accounts for less than 10% of the total water found in pre-rigor meat. Bound water, on the other hand, is held very tightly to proteins and makes up a very small portion of the total water in muscle, approximately 0.5% of the water in muscle is truly bound.