![]() ![]() Temperature Measurement Principle Resistive electrolyticSurface-IR and NTC ![]() This instrument will work for those with modest requirements on accuracy and reproducability. It's simple to operate and provides basic measurement functions, but doesn't sacrifice quality.īuilt-in automatic equilibrium detection and a well-proven resistive-electrolytic sensor offer high accuracy. The LabStart-aw is a budget water activity meter for users testing this for the first time. It also has implication on color, taste and aroma. In addition to influencing microbial spoilage, water activity can affect the activity of enzymes and vitamins in foods. For example, bacteria does not grow at water activities below aw 0.9 and most molds cease to grow at water activities below aw 0.80.īy measuring water activity it is possible to predict which microorganisms will be possible sources of spoilage. It affects shelf life, safety, texture, flavor and smell. Water activity (aw) is a critical factor in determining quality and safety of foods. (A condition of equilibrium)Īt equilibrium the relative humidity of the air in the chamber is measured. The relation of this reading to pure water is the water activity measurement expressed as the term aw. The range of water activity is from zero (no free water) to 1.0 (pure water) Why is Water Activity Important? The free water is allowed to escape into the air in the chamber. it remains there until all the free water has left the sample. The typical system uses a sealed temperature controlled chamber. A sample is placed in the chamber and sealed. Water Content is not Water activity but is the total amount of water in a product - both Bound Water and Free Water. This unattached water is referred to as “ Free" water, while the unavailable water is called “ Bound”. Water activity is a measure of water in a material that is available to react with or attach itself to another material.
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