Lecture 11: Fats & Oils

Question 1

Definition of lipids

Answer 1

• Aka fats & oils

- Organic compounds (CHO) that don’t mix with water

Question 2

Most common lipid?

Answer 2

Triglycerides (3 fatty acids attached to glycerol)

Question 3

calorie

Answer 3

1 calories raises 1 gram of water 1 C

Question 4

kcal

Answer 4

1 kcal raises 1000 grams of water 1 C

-aka Calorie or Big Calorie

Question 5

Caloric value of carbohydrates

Answer 5

4 kcals/gram

Question 6

Caloric value of proteins

Answer 6

4 kcals/gram

Question 7

Caloric value of fats

Answer 7

9 kcals/gram

Question 8

USDA recommendations for fat intake

Answer 8

• Diet low in fat, saturated fat, cholesterol, trans fat

- Eat less than 35% of total calories from fats & oils (keep it between 20-35%)

Question 9

Lipases

Answer 9

• Enzymes that break down lipids so that the free fatty acids can be absorbed
• Take part in triglyceride hydrolysis

Question 10

Vegetable oil

Answer 10

Triglyceride extracted from a plant

Question 11

From what are edible oils extracted from

Answer 11

Plant seeds

Question 12

What is the largest quantity of all vegetable oil produced worldwide?

Answer 12

Palm oil

Question 13

What is the largest quantity of edible vegetable oil produced worldwide?

Answer 13

Soybean oil

Question 14

Mechanical extraction

Answer 14

Older method of crushing or pressing to produce the more traditional oils (olive, palm)

Question 15

Solvent extraction

Answer 15

• Used for most of the “newer” industrial oils (soybean, corn)
• Most common solvent is petroleum-derived hexane

Question 16

Centrifugation

Answer 16

After extraction, this process separates water and oil

Question 17

Virgin olive oil

Answer 17

Oil that is extracted from olives using purely mechanical means

Question 18

Difference between fats and oils

Answer 18

• Fats are semi-solids at room temp

- Oils are liquid at room temp

Question 19

How does the food industry label fats in foods

Answer 19

• Percent by weight
• Like to tell you how much fat isn’t there
• “95% fat free” as opposed to “5% fat”

Question 20

How does diluting food with water change fat content?

Answer 20

-Percentage of fat by weight will go down, but the percent of calories from fat will not change

Question 21

Simplesse

Answer 21

• Made from dairy and egg proteins
• Can be formulated as a powder
• May have problems with heating
• 1 cal vs. 9 cal (regular fats)
• Manufactures recommend food label is “dairy protein”

Question 22

Olestra

Answer 22

• Chemically bonds fatty acids onto sugar molecules

- So large that they’re indigestible

Question 23

Controversy over Olestra as a fat substitute

Answer 23

-Olestra claimed to be able to reduce people’s caloric intake & help w/ weight loss
PROBLEMS:
-Quantity of intake doesn’t change or increases —> no weight loss
-People’s different biological reactions to Olestra —> doesn’t work for everyone
-Higher quantities interfere w/ absorption of some vitamins derived from fatty acids

Question 24

Melting point of saturated fatty acids

Answer 24

~ 65 C

Question 25

Melting point of mono-unsaturated fatty acids

Answer 25

~ +10 C

Question 26

Melting point of poly-unsaturated fatty acids

Answer 26

~ -10 C

Question 27

Why are unsaturated fatty acids not a straight carbon chain like saturated fatty acids?

Answer 27

The carbons don't hold hydrogens as well, so C makes double bonds to make up for it --> double bonds cause the "bend" in the structure

Question 28

Polymorphism

Answer 28

More than one form of a substance - different shapes & ways to be packed together - different melting poinds

Question 29

Which crystal form of cocoa butter is the "nicest" for making chocolate?

Answer 29

Type V

Question 30

How do you make all cocoa butter crystals type V?

Answer 30

Controlled heating and cooling

Question 31

Temeperin

Answer 31

Describes controlled crystal formation in chocolate

Question 32

Role of fat in meats

Answer 32

USDA grading is based on fat distribution (marbling of meat) | -More fat = more prime

Question 33

Essential fatty acids

Answer 33

- Essential to proper metabolism - Cannot be synthesized by the body (in sufficient amounts) - Ex) Omega 3, 6

Question 34

Role of fats in flavor

Answer 34

-Storage of flavor compounds specific for a product that give foods distinct texture/flavor

Question 35

Role of fats in heat transfer

Answer 35

-Large molecules don't evaporate and can be heated to very high temps

Question 36

Frying

Answer 36

Heat transfer with hot fat

Question 37

List meat grades from least to greatest amount of marbling

Answer 37

- Cutter - Utility - Standard - Select - Choice - Prime