Water

ImportanceWater makes up 55-60% of

the human body!Losing 10% could cause deathMajor function for life

Digesting foodTransporting nutrientsLubricant Regulate body temperature

Water Structure

Specific HeatMore energy to heat water than any other substance

Freezing Point32°F/0°CLower temp decreases kinetic energy (motion)

Becomes less dense and floats

If something is added the freezing point changes

Melting PointThe temperature at which a solid changes to a liquid

Boiling PointPressure of

steam=Pressure of atmosphere pushing down

212°F at sea levelWater will continue to get

hotter as heat is continually applied

Food may cook faster

Atmospheric Pressure

Steam Pressure

=

Atmosphere

Less Atmospheric pressure

More atmospheric pressure

==

Lower boiling point

Higher boiling point

At Sea Level

= 212 F

BELOW SEA LEVELABOVE SEA LEVEL

Water & FoodRanges from 0-95%Fruits and Veggies have the most

Grains and vegetable oils have the least

WATER CONTENT

FREE WATERWATER THAT READILY SEPARATES FROM FOODS THAT ARE SLICED, DICED, OR DRIED BREAD CRISPING IN THE TOASTER

BOUND WATERWATER THAT CANNOT BE SEPARATED IN FOOD Look at the next slide, would you

think of drinking a tomato?

Water Content in Foods

0102030405060708090

100

Food

Wat

er

215

36 37

6074 75

87 87 8893

Functions in FoodHeat transferUniversal solventChemical reactions

Food preservation

Heat TransferEnsures heat is evenly distributedEx: Baked Potato

Moist-Heat CookingBoiling, simmering, steaming, stewing and braising

Universal SolventBiochemical reactions

occurring in living thingsWater forms solutions

with minerals and water-soluble vitamins

Water dissolves caffeine and other flavor compounds

Definitions Solvent – a substance, usually

a liquid, in which another substance is dissolved

Solute – solid, liquid or gas compounds dissolved in another substance

Solution – A mixture of a solute dissolved in a solvent

Gas-in-water solutions

Carbonated beverages

Liquid in water solutions

Fruit juice concentrates

Vinegar & water (used to preserve pickled foods)

Solid-in-water solutionsMost common are sugar & salt

Cause water to freeze at lower temperature

Cause water to boil at higher temperature

Chemical Reactions Makes nonessential amino

acids Helps enzymes function Hydrolysis – water breaks down

a chemical bond making a new substance Break down carbs, fats, & proteins for

energy Release of Carbon Dioxide

Food PreservationWater is important for the life of microorganisms

Dehydrating food helps inhibit the growth of microorganisms

WATER TRIVIA

WATER IS IN EVERY BODY CELL WATER DETERMINES THE

SHAPE, SIZE, & FIRMNESS OF CELLS

REVIEW:How does water’s

function as a solvent play a role in human nutrition?

How does water help the body release excess heat?

Name 3 foods that are more than 50% water.