Lecture 11: Fats & Oils Flashcards Preview

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Flashcards in Lecture 11: Fats & Oils Deck (37):
1

Definition of lipids

-Aka fats & oils
-Organic compounds (CHO) that don't mix with water

2

Most common lipid?

Triglycerides (3 fatty acids attached to glycerol)

3

calorie

1 calories raises 1 gram of water 1 C

4

kcal

1 kcal raises 1000 grams of water 1 C
-aka Calorie or Big Calorie

5

Caloric value of carbohydrates

4 kcals/gram

6

Caloric value of proteins

4 kcals/gram

7

Caloric value of fats

9 kcals/gram

8

USDA recommendations for fat intake

-Diet low in fat, saturated fat, cholesterol, trans fat
-Eat less than 35% of total calories from fats & oils (keep it between 20-35%)

9

Lipases

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

10

Vegetable oil

Triglyceride extracted from a plant

11

From what are edible oils extracted from

Plant seeds

12

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

Palm oil

13

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

Soybean oil

14

Mechanical extraction

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

15

Solvent extraction

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

16

Centrifugation

After extraction, this process separates water and oil

17

Virgin olive oil

Oil that is extracted from olives using purely mechanical means

18

Difference between fats and oils

-Fats are semi-solids at room temp
-Oils are liquid at room temp

19

How does the food industry label fats in foods

-Percent by weight
-Like to tell you how much fat isn't there
-"95% fat free" as opposed to "5% fat"

20

How does diluting food with water change fat content?

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

21

Simplesse

-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"

22

Olestra

-Chemically bonds fatty acids onto sugar molecules
-So large that they're indigestible

23

Controversy over Olestra as a fat substitute

-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

24

Melting point of saturated fatty acids

~ 65 C

25

Melting point of mono-unsaturated fatty acids

~ +10 C

26

Melting point of poly-unsaturated fatty acids

~ -10 C

27

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

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

28

Polymorphism

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

29

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

Type V

30

How do you make all cocoa butter crystals type V?

Controlled heating and cooling

31

Temeperin

Describes controlled crystal formation in chocolate

32

Role of fat in meats

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

33

Essential fatty acids

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

34

Role of fats in flavor

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

35

Role of fats in heat transfer

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

36

Frying

Heat transfer with hot fat

37

List meat grades from least to greatest amount of marbling

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