Subtopic: Water activity, sorption and desorption isotherms
Question Statement:
Water activity (aw) is a ratio of
Options:
(A) vapour pressure of water to partial pressure of water in the product
(B) partial pressure of water in air to partial pressure of air at saturation
(C) vapour pressure of water in equilibrium with the food to vapour pressure of pure water at the same temperature
(D) vapour pressure of pure water to vapour pressure of water in equilibrium with food
Official Answer Key:
C
Step-by-Step Solution & Explanation
By definition, aw = p/p₀, where p is the equilibrium (partial) vapour pressure of water above the food and p₀ is the saturation vapour pressure of pure water at the same temperature.
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