Food Engineering
Water sorption isotherm
A curve relating equilibrium moisture content to water activity at constant temperature, typically sigmoidal.
Used to decide the right packaging material and shelf-life claim for dry products like biscuits, namkeen and spice mixes.
Related terms
Water activity
Food ChemistryThe ratio of the vapour pressure of water in a food to the vapour pressure of pure water at the same temperature. It measures how much water is available for microbial growth and chemical reactions — not how much water is present.
Moisture content
Food ChemistryThe total amount of water in a food, expressed on a wet basis (mass of water per mass of wet sample) or dry basis (mass of water per mass of dry solids).
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