Water Activity

Question 1

Water activity values strictly range from 0 to 1 in food as well as non-food systems. T/F

Answer 1

False

While in food the water activity is usually from 0-1 it does go beyond that range

Question 2

As per the 1st principle of Scott’s Theorem, a 70 % RH means that ____ % of water is free and ____ % is bound.

Answer 2

70,30

Question 3

All frozen food materials, irrespective of the type of food, having a water activity of 0.85 will have a freezing point of -18 degrees centigrade. T/F

Answer 3

True

Question 4

Moisture absorption isotherm is a plot of _________ (Y-axis) versus _______ (X-axis).

Answer 4

Moisture Content, Water Activity

Question 5

Water Activity and Moisture: Extensive or Intensive Properties

Answer 5

Water Activity: Intensive - does NOT depend on the amount of material

Moisture: Extensive - Does depend on the amount of material

Question 6

The growth of ALL pathogen growth is prevented in foods with a water activity below 0.85. T/F

Answer 6

False

That is Dumb

Question 7

A layer of chocolate on an ice cream cone helps to prevents the cone from getting soft by

Answer 7

Preventing water migration from high water activity ice cream to low water activity cone

Question 8

When NaCl is dissolved in water, the resultant solution will have a ________ boiling point and ______ freezing point than pure water.

Answer 8

Higher, Lower

Question 9

Water Activity

Answer 9

the thermodynamic mic capacity (energy status) or the effective concentration of water in a food material that can actually participate as a chemical agent in various biological and chemical processes

Water “bound” to chemical groups (proteins, polysaccharides, etc.) causes a fraction of water in foods to become bound to the food matrix, resulting in a decrease in the effective concentration of water available for chemical and biological processes