Topic 4: Part A

Question 1

Water is an..

Answer 1

essential nutrient

Question 2

We can survive how many days without water and food

Answer 2

• food: 60 days

- water: 4 days

Question 3

In the body water becomes the ..

Answer 3

fluid in which all life processes occur

Question 4

Every cell contains fluid of the exact composition that is best for that cell called…

Answer 4

intracellular fluid and is bathed externally in another fluid (interstitial fluid)

Question 5

Water constitutes how much of an adults body weight

Answer 5

60% (higher in children)

Question 6

Water makes up what percent of weight of lean tissue and fat

Answer 6

• 75% of lean tissue

- 25% of fat

Question 7

Proportion of water is generally smaller in …

Answer 7

females, obese people, elderly because of their smaller proportion of lean tissue

Question 8

Found in high levels of water in foods

Answer 8

lettuce (98%), celery (95%), carrots (88%), whole milk (88%), apple (84%), ice cream (61%), ham (53%).

Question 9

Moderate to low levels of water in foods

Answer 9

french fries (38%), white bread (37%), dried apple (32%), popcorn (4%), peanuts (2%).

Question 10

Much of the water in plant and animal tissue is held..

Answer 10

inside the cells (intracellular)

Question 11

In many cases water is held within the cell as a ..

Answer 11

hydrate which means int doesn’t flow from the cell when the tissue is torn

Question 12

Ability of food to hold water is called its..

Answer 12

water holding capacity

Question 13

Some water in foods is held extremely tight and called..

Answer 13

bound water

Question 14

Bound water

Answer 14

becomes part of the structure of large molecules such as proteins and carbs and no longer has same properties as free water

Question 15

The perishability go a food is related to its..

Answer 15

Aw

Question 16

Water activity is reported on a scale of 0 to 1 and fresh meat, fruit, veggies have Aw of.. and dried meats have Aw of ..

Answer 16

• 0.95-1

- 0.2-0.4

Question 17

Most bacteria can not grow below …

Answer 17

0.9

Question 18

Yeasts cannot grow below..

Answer 18

0.85

Question 19

Molds cannot grow below..

Answer 19

0.7

Question 20

Clostridium botulinum can grow and produce at..

Answer 20

0.95

Question 21

Staph. Aureus can grow at..

Answer 21

0.86

Question 22

Decreasing the Aw to increase shelf life can be done by..

Answer 22

• physically removing the water (drying)
• addition of solutes which ties up water
• by adding humctant to absorb excess moisture

Question 23

Water is a critical in microwave heating of food because it is..

Answer 23

the water molecules that respond to the microwave energy. the energy causes water to oscillate thereby causing friction which creates heat

Question 24

Microwaves penetrate the first ..

Answer 24

2-3cm of food and remainder of food is heated bag conduction

Question 25

Microwaves DO NOT ..

Answer 25

heat food from inside out

Question 26

Water is an important..

Answer 26

solvent. many flour molecules are dissolved in water (coffee, tea) and sugars dissolved in water (juices)

Question 27

Starch granules are first dispersed in water and then the mixture is heated, the starch granules…

Answer 27

absorb water to produce a thickened pudding or sauce

Question 28

Roles of water in food preparation

Answer 28

• solvent
• cooking medium
• cleaning agent
• chemical changes
• hydrolysis
• as an ingredient

Question 29

Water as a cleaning agent

Answer 29

removes soil, residues, microorganisms depending on the rigour used in washing

Question 30

Water promotes chemical changes

Answer 30

left dry these agent don’t react but when water is added carbon dioxide is realized which leavens products such as cakes, muffins

Question 31

Hydrolysis

Answer 31

refers to breaking of chemical linkages between units of large or complex molecule sot yield smaller molecules and becomes part of these smaller molecules (starch becomes glucose)

Question 32

Chemicals found in water

Answer 32

• calcium
• fluoride
• chlorine
• nitrates
• ozone
• lead
• organic chemicals
• microorganisms

Question 33

Calcium

Answer 33

and other minerals from rocks and soil provide dietary source of minerals but may make water “hard”

Question 34

Fluoride

Answer 34

added to water, important in teeth and bone fermentation

Question 35

Chlorine

Answer 35

added to water to kill harmful microorganisms

Question 36

Nitrites

Answer 36

may be present from fertilizers, manure, and sewage

Question 37

Ozone

Answer 37

added to control bacterial growth in water. preferably used because it doesn’t give water an aftertaste

Question 38

Lead

Answer 38

found in water from lead pipes

Question 39

High levels of microorganisms in water

Answer 39

from animal or human waste resulting in cholera, dystentery, typhoid

Question 40

Soft vs hard water is a present of ..

Answer 40

mineral salts determine water hardness

Question 41

Temporarily hard water

Answer 41

contains bicarbonate can be softened by boiling during which minerals such calcium, magnesium, and iron precipitate out

Question 42

Permanently hard water

Answer 42

cannot be softened by boiling because the minerals aren’t precipitated by heat

Question 43

Permanently hard water can be softened by …

Answer 43

exchanging sodium ions for the calcium and magnesium ions (results in very high levels of sodium)

Question 44

Hardness causes ..

Answer 44

scale build-up on equipment and pipe

Question 45

Hard water usually alkaline can affect..

Answer 45

plant pigments when cooking vegetables (red cabbage to green)