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Moisture is an important component in the baking process.

Moisture

Also Known As Water, Water Content, Moisture Content


What is Moisture?

The amount of water present in a system, expressed in a percentage value. The moisture of a product is measured by (Tw – Dw)/Tw x 100 (Where Tw = total weight of product, Dw = dried weight of product).

Function

Moisture levels are a vital measurement in the food industry as well as the baking industry. Appearance, texture, mouthfeel and overall quality are all attributes influenced by moisture levels. Water is a very low cost ingredient, therefore manufacturers attempt to use as great amount of water as possible to diminish costs while still maintaining a high quality product.

Maintaining moisture content on the dry end of the spectrum is imperative to prolonging shelf life. Conditions within the products environment such as humidity, temperature, tightness of container seal, and packaging material also plays a role in moisture content.

Application

Three common ways of measuring moisture levels in grain based foods are:

  1. Distillation.
  2. Oven drying.
  3. Near Infrared (NIR).

Although moisture level is a good indicator of an efficient process and/ or texture of food, it is not a good indicator of perishability. It has been noted that various food with the same moisture level have different perishability. This is due to the presence of ‘free’ water and ‘bound’ water in the food.

Only ‘free’ water has the ability to support microbial growth, and the term ‘water activity’ or aw was developed to help describe the amount of ‘free’ water. The higher the aw, the more likely the food will support microbial growth. The lower the aw, the less likely the food will have microbial spoilage, and the longer its shelf life. There is a non-linear but direct correlation between moisture levels and aw.