10 Questions
What is the water activity limit for the growth of molds and yeasts?
Between 0.8 and 0.9
What water activity level is required for most enzymatic reactions?
0.85 or higher
What is the relationship between water activity and chemical reactions?
Exhibits more complex behavior with maxima and minima
What is the glassy state in foods?
A metastable state capable of undergoing change
What is the subject of strong interest among food scientists?
Molecular mobility
What are the two variables that affect the physical properties and stability of a concentrated aqueous solution of sugars?
concentration and temperature
What happens when the concentration of a liquid food product is increased by slowly removing some of the water and the temperature is lowered gradually?
solid crystals of sugar will be formed
What is the result of carrying out the process of concentration and cooling under different conditions?
the viscosity of the solution will increase until a rigid, transparent, glass-like material will be obtained
What is an example of a glassy (vitreous) food?
transparent hard candy
Is the glassy state limited to sugar-water systems?
No, it is not limited to sugar–water systems
Test your knowledge on the effect of water activity on food quality and stability. Learn about the water activity limits for bacterial growth, molds and yeasts, and enzymatic reactions. Discover the relationship between water activity and chemical reactions in the Maillard browning process.
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