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1

What is olestra?

"fat free fat"

a FA attached to a sugar

can't be metabolized

2

chemical characterization of lipids?

insolubility of in water

soluble in non polar organic solvents

3

3 classes of lipids?

1. simple
2 compound
3 derived

4

categories of simple lipids?

fats and waxes

5

types of compound lipids?

phospholipids
glycolipids
lipoproteins

6

what are simple lipids?

esters of FA connected to an alcohol

7

types of derived lipids?

fatty acids
fatty alcohols
hydrocarbons

8

what are fats (simple lipids)?

another name?

esters of FA connected to glycerol

R1 R2 R3 are FA (short to long chain aliphatic hydrocarbons with a COOH group at one end)

aka triacylglycerols/triglycerides

9

oil vs fat?

oil: low mp and liquid at room temp

fat: solid at room temp

10

percent of triglycerides in extractable lipid material in biological systems and in lipid that we consume?

>90%

11

melting profile of pure triglyceride vs edible fat?

triacylglycerol has a very sharp melting point

edible fat melts over a wider range of temp because it is a mixture of different triacylglycerol molecules

12

chemical structure of waxes?

FA esterified with a simple fatty alcohol (other than glycerol)

aliphatic alcohol + FA = wax

13

what is a true wax

FA esterified to a SIMPLE fatty alcohol

14

uses of waxes?

sources of wax?

sealing agents (cheese)
polishing agents (apples)

sources: injojoba oil, beesewax

15

jojoba oil structure and use?

structure: linear esters of mono unsat long chain FA esterified to fatty alcohols

use: cosmetics. low cal ingredient (not digested readily)

16

structure of cholesterol?

FA esterified to a complex alcohol

17

what are compound lipids? types?

simple lipid conjugated to a non lipid

18

structure of phospholipids?

what is the base structure?

what are the different phosphatidic acid molecule examples?

triglycerides with one FA replaced with a nonlipid moiety - phosphoric acid

base structure = phosphatidic acid (when X=OH)

other phospholipids: X=nitrogenous base

19

classes of phospholipids

1. lecithins (phosphatidyl cholines)
2. Cephalins (phosphatidyl ethanolamines): phosphatidic acid conjugated to ethanolamine (x=OH-CH2-CH2-NH2)
3. Phosphatidyl inositols: non nitrogenous group + phosphatidic acid

20

hydrophilicity of phospholipids?

how much is found in food systems?

contains both hydrophobic and hydrophillic groups

thus, good emulsifier (ie soybean oil )

in food systems: comprises <5% of lipid material

21

what are glycolipids and sphingo lipids?

structure?

examples of glycolipids in cell membranes?

in cell membrane lipids in plants and animals

complex structure: combination of glycerol backbone, FA, carb, nitrogenous group

ex in cell membranes: glycoproteins, glycolipid, glycocalix

22

role and structure of lipoproteins?

circulates in blood to carry lipids to tissues for metabolism or storage

HDL and LDL (different sizes and levels of protein, fat and cholesterol)

structure:
inside: triglyceride + cholesterol esters
outside: phospholipid + cholesterol + apolipoprotin

23

LDL vs HDL?

HDL: good. accounts for 1/3 of blood circulating cholesterol. protective to heart disease

LDL: excess = plaque in blood vessels = artery blockages

24

what are derived lipids?

derived from simple of compound lipid categories. Still retains hydrophobic character

25

types of derived lipids (3)

Role in food systems?

1. fatty acids
2. fatty alcohols
3. hydrocarbons and oxygenated derivatives


role in food systems: major role in functionality

26

structure of fatty acids (as type of derived lipids)?

short to long chain aliphatic hydrocarbons w/ COOH group at one end

27

what are short chain FA important for?

ex?

flavour compounds

can be released by lipolysis

ex:
butyric acid (C3)
Caproic acid (c6)
caprylic acid (c8) --> rancid cheese flavor

28

what can presence of FFA do?

lower the smoke point of edible oils when used for frying

29

do long chain free fatty acids have flavour?

no

but can give soapy flavour in presence of mineral salts

30

short chain alcohols are...

more complex derived alcohols are....

1. major contributors to flavour

2. often biologically active (ie cholesterol)