Teaching Science with Food

What is pH?

the symbol used to express the acidity or alkalinity of a solution on a scale of 0 to 14, where less than 7 represents acidity, 7 neutrality, and more than 7 alkalinity.

CAN FOOD HAVE AN EFFECT ON THE BLOODS PH LEVEL?

.

no- no food is as acidic as the gastric juice secreted by the walls of the stomach

HOW DO ACIDS TASTE?

THEY TASTE SOUR.

Does the fact that a food is acidic or basic have any affect on how it is prepared and stored?

higher the pH, a cake will be tough and heavy- chocolate cakes will turn a shade of red as the pH increases.

A low pH will permit food to be stored at a longer period of time.

Chemical reactions occur as a result of ion exchanges in water

Water contains hydrogen (+) and hydroxide (-) ions.

If the solution has an equal amount of hydrogen and hydroxide ions then it is considered neutral.Neutral on scale is 6-9.

Less hydrogen ions make the food acid 1-5 scaleLess hydroxide ions make the food basic 10-14 scale

Vocab Term- Chemical Reactiona process that involves changes in the structure and energy content of atoms

Vocab term- Ion Exchange: the process in which ions are exchanged between a solution and an insoluble solid,

Vocab Term- hydrogen ionsElectrically charged hydrogen atom

Vocab term- Hydroxide IonsAn electrically charged hydrogen and oxygen atom

Vocab Term- Gastric juicesthe digestive fluid, containing pepsin and other enzymes

pH lab- determine the pH level for each of the liquids provided and answer the following questions on the back of your lab sheet.

During the lab use the scale found at the following site.www.elmhurst.edu

Questions

•Why would most people expect that the orange juice and tomato sauce have a low pH number?•Why would you expect the pH level to

raise during the second part of the test?•

Teaching Science with food Part 2

No more brown bananas

• 1. 1/3c. Water and vitamin c pill crushed in bowl- dip fruit• 2. 1/3c. Vinegar in bowl- dip fruit• 3. 1/3 c. lemon juice in bowl- dip fruit• 4. 1/3 c. water in a bowl- dip fruit• 5. 1/3 c. water- keep fruit in it• 6. fruit• 7. fruit with cover

• Begin to fill in chart

Why do apples turn brown?

Oxygen in the air reacts to the chemicals in the fruit and makes it turn brown.

How can we keep the apple from turning brown?

Vitamin C added to the apple will keep it from turning brown.

Vocab Term- Enzymatic browningdiscoloration caused by an enzyme chemical reaction that causes the fruit to turn brown

Vocab Term- Enzymestype of protein that controls how quickly chemical reactions occur

Vocab Term- Polyphenol oxidaseenzyme naturally found in fruits and vegetables to turn brown when injured

Vocab Term- denature- to inactivate proteins such as enzymes (Use acids- vinegar, citric acid, vitamin C)

Complete the Enzymatic browning lab and questions.

Teaching Science with food Part 3

MyPlate Review• How much fruit do we need daily?• How many vegetables do we need daily?• What are the different types of vegetables?• Give one benefit of eating fruits.• Give one benefit of eating vegetables.

Watch the teacher lab demonstration “pH and cooking Vegetables”While vegetables are cooking, we will complete the cooking lab sheets.