Lecture 11: Lipids Flashcards Preview

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Flashcards in Lecture 11: Lipids Deck (38):
1

General uses of lipids

foods
soaps
candles
paints
lubricants
biofuel

2

What is the most common form of lipid?

Triglycerides

3

What is the caloric value of Carbohydrates, proteins and fats?

Carbs: 4 kcal/gram
Proteins: 4 kcal/gram
Fats: 9 kcal/gram

4

Calorie

Amount of energy it takes to raise water 1 degree C

5

What does the USDA recommend for fat intake?

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

6

Trigycerides

3 fatty acids attached to glycerol

7

Triglyceride hydrolysis

During digestion we need to hydrolyze the fatty acids off the glycerol
Lipids break down lipases

8

What is the importance of triglyceride hydrolysis?

Only free fatty acids are absorbed

9

Vegetable oil

Is triglyceride extracted from a plant
Been used for millennia
Edible oil is extracted primarily from seeds

10

What is the largest quantity of all vegetable oils

Palm oil

11

What is the largest in quantity of all edible vegetables oils

Soybean

12

Mechanical extraction of oil

"crushing" or "pressing"

13

Solvent extraction

the most common solvent is petroleum-derived hexane
This technique is used for most of the "newer" industrial oils such as soybean and corn oils

14

How is olive oil made?

After crushing of the fruit, water and oil can also be easily separated by centrifugation

15

What does virgin mean in virgin olive oil?

"That the oil has been extracted from the olives using purely mechanical means"

16

What is the difference between Fats and Oils

Fats are (semi)-solid at room temperature
Oils are liquid at room temperature

17

How are fat percentages defined?

Food industry labels fat% by weight and they like to tell you how fat isn't there
ex: 95% Fat Free means 5% fat

18

What is the recommended fat % in your daily diet?

<30% (+/-) by calories

19

What happens to the fat % when we add water?

when diluting a food with water, the % fat by weight will go down
But by diluting with water does not change the % of calories from fat

20

Simplesse

low fat types
made from dairy and egg proteins
can be formulated as a powder
may have problems with heating
1 calorie vs. 9 calories
"dairy protein"

21

Olestre

low-fat types
chemically bond fatty acids onto sugar molecules
so large, they are indigectible

22

Saturated acids melting point

high melting points
~65 degree C (fat)

23

Mono-unsaturated fatty acids melting point

low melting point
~10 degree C (oil)

24

Poly-unsaturated fatty acids melting point

even lower Melting point
~ -10 degree C (oil)

25

Triglycerides from plants vs. animals?
Chocolate??

Beef: 50% sat, 50% unsat
Cocoa: 60% sat, 40% unsat

26

Polymorphism

there are six essential polymorphic forms. The polymorphic transformation theory is based on the fact that bloomed chocolates are always found to contain the most stable VI polymorph of cocoa butter. According to this theory, bloom occurs through the uncontrolled polymorphic transformation of cocoa butter from a less stable form (form IV or V) to the most stable form (form VI)

27

Cocoa butter forms how many crystals?

6
which is the most stable

28

Temepering

controlled crystal formation in chocolate

29

Beta crystals

what allows chocolate to stay solid in our hands

30

You get to type 5 chocolate by...

heating and cooling
type 5 crystals is the best

31

What are the roles of fats?

-energy source
-texture
-adipose
-essential fatty acids
Fat soluble vitamins: A, D, E, K
Flavor
heat transfer
fatty acid isomers (trans fat)

32

Prostaglandins

most common essential fatty acid

33

Flavor roles of fat

1. storage of flavor compounds
2. Specific for a product
3. without fat there is little flavor

34

Roles of Fat: Heat transfer

the large molecules do not evaporate
-can be heated to very high tempetures
-frying

35

Marbling

distribution of fat throughout meat tissue

36

What meat grade has the greatest amount of marbling

choice

37

What causes the formation of "chunky butter"

different forms of fat crystals

38

How many double bonds does a saturated fat have?

0