STM3183 MSI

What characterizes Zone I in the moisture sorption isotherm?

• Water is freezable and acts as a solvent.

• Water is strongly sorbed and behaves as part of the solid.

• Water occupies the first layer sites and is highly mobile.

• Water is primarily involved in oxidation reactions.

What happens at the end of Zone II?

• Viscosity remains unchanged.

• Water is completely unfreezable.

• Significant plasticizing action on solutes occurs.

• Oxidation rates are at their highest.

How does the addition of water affect oxidation in Zone I?

• It decreases the rate of oxidation until a monolayer is formed.

• It completely prevents oxidation.

• It has no effect on oxidation rates.

• It accelerates oxidation by increasing O2 solubility.

What is the effect of high water activity (aw) on the browning reaction?

• It enhances the catalytic activity of enzymes.

• It has no effect on the reaction rate.

• It increases the reaction rate significantly.

• It dilutes rate-enhancing components and decreases the reaction rate.

What is the relationship between enzyme activity and water activity?

• Enzyme activity is highest at low aw.

• Enzyme activity increases with increasing aw.

• Enzyme activity is independent of water activity.

• Enzyme activity decreases with increasing aw.

What occurs in Zone III of the moisture sorption isotherm?

• There is a large decrease in viscosity and high molecular mobility.

• Water is completely bound and does not support microbial growth.

• Water is strongly sorbed and unfreezable.

• Water acts as a plasticizer for solutes.