PRELAB 1: Moisture

Question 1

Drying means

Answer 1

remove and or bind moisture

Question 2

_____ is one of the traditional methods of food preservation

Answer 2

drying

Question 3

____ is used to control the moisture by affecting the ______ through ____

Answer 3

Humectant
humidity
fluctuations

Question 4

example of a humectant that
can be found in chip packages to help
maintain their crispiness

Answer 4

Silica gel

Question 4

Humectants are what

Answer 4

change the moisture by fluctuating the humidity; to maintain the moisture level

Question 5

Other examples of humectants

Answer 5

salt
sugar
glycerin
honey

Question 6

What is water activity

Answer 6

the amount of free water in food medium or amount of water available for chemical reaction and microbial growth

Question 7

The effect of moisture is determined via

Answer 7

Aw - water activity

Question 8

The formula for water activity

Answer 8

Aw = p/P sub O
p = water vapor pressure / Vapor pressure of a solution
P0= Vapor pressure of pure water/ solvent

Question 9

Aw for most fresh food

Answer 9

0.99

Question 10

Aw Spoilage Bacteria

Answer 10

0.9-0.91

Question 11

Aw Yeast

Answer 11

0.88

Question 12

Aw for molds

Answer 12

0.80

Question 13

Microbial growth and AW for halophiles

Answer 13

0.75

Question 14

What are Xerophilic molds
Example
Aw

Answer 14

dry loving molds
Trichosporonoides nigrescens
Zygosaccharomyces spp.
0.61

Question 15

Organisms that can survive in high osmotic pressure
Aw

Answer 15

Osmophili yeast
0.61

Question 16

Lowest Aw for pathogen growth

Answer 16

0.86
- except S. aureus that can survive but not grow in this Aw