lipids

Question 1

what is the diff between fats and oils?

Answer 1

fats solid, oils liquid at room temp

Question 2

crude oil is _____% TAGs, ___% non-TAG

Answer 2

93-98; 2-7

Question 3

TAGs prefer the __ conformation

Answer 3

chair

Question 4

C 4:0

Answer 4

butyric acid (milk)

Question 5

C 10:0

Answer 5

capric acid (milk)

Question 6

c 12:0

Answer 6

lauric acid (coconut, palm kernel)

Question 7

C 14:0

Answer 7

myristic acid (milk)

Question 8

C 16:0

Answer 8

palmitic acid (palm, milk)

Question 9

C 18:0

Answer 9

stearic acid (milk)

Question 10

C 18:1

Answer 10

oleic acid (olive oil, milk)

Question 11

C 18:2

Answer 11

linoleic acid (sunflower, canola, soybean)

Question 12

C 18:3

Answer 12

linolenic acid (flaxseed, borage)

Question 13

C 20:5

Answer 13

eicosapentaenoic acid

Question 14

C 22:6

Answer 14

docosahexaenoic acid

Question 15

C 22:5

Answer 15

docosapentaenoic acid

Question 16

TFAs are found in:

Answer 16

dairy/animal fat and also hydrogenated vegetable oils

Question 17

_____ oil is found in rapeseed and mustard

Answer 17

erucic acid

Question 18

lauric oils are particularly important for _____

Answer 18

soap making

Question 19

______ have wide melting points ranging from -40 to 40 degrees C

Answer 19

milk fats

Question 20

Palmitic oils are widely grown in ___ and are rich in ___

Answer 20

Malaysia; beta carotene

Question 21

what is vegetable butter derived from?

Answer 21

palmitic, stearic, oleic acids (saturated–>solid)

Question 22

animal fats have lots of _____ TAGs, giving them a high ___

Answer 22

fully saturated; melting point

Question 23

the most common type of vegetable oils are ___, that make up _____%

Answer 23

oleic/linoleic; 80-90

Question 24

why shouldn’t you use olive oil for high temp frying?

Answer 24

the high amount of monounsaturates means that it oxidizes easily with metal elements in pan

Question 25

very high unsaturation leads to _____ and development of ___ flavour

Answer 25

auto-oxidation; rancid

Question 26

this type of oil is used for its excellent drying properties in the paint industry

Answer 26

linolenic oils (camelina, flax)

Question 27

C 22:1

Answer 27

erucic acid (edible oils in china and india, industrial oil in NA)

Question 28

the genetic mod of rapeseed developed in uni of Sask; must have

Answer 28

canola

Question 29

marine and fish oils have very __ melting points because of the presence of ___

Answer 29

low; PUFAs

Question 30

what are the 3 major vegetable oils?

Answer 30

palm, rapeseed, soybean

Question 31

what are the steps of industrial production of vegetable oil?

Answer 31

seed collection/cleaning, extraction of crude oil (pressing, solvent extraction), refining

Question 32

what needs to be removed in the refining process of crude oil?

Answer 32

phospholipids (degumming), free f.a. (alkali neutralization with NaOH), undesirable colour (bleaching), undesirable odours (deodorizing)

Question 33

what is the miscella?

Answer 33

oil and solvent mix after pressing/extraction (solvent must be evaporated to get crude oil)

Question 34

what is lecithin?

Answer 34

an emulsifier used in degumming

Question 35

what are soapstocks?

Answer 35

sodium salt of free f.a. after the neutralization process

Question 36

what are the diff chem tests of fats and oils?

Answer 36

acid value, saponification value, iodine value, smoke point

Question 37

a higher smoke point = ___ for frying

Answer 37

better

Question 38

what is the iodine value? It is expressed as _____

Answer 38

degree of unsaturation; # I (g) absorbed by 100g oil

Question 39

what is the saponification value? It is defined as __

Answer 39

f.a. chain length and amount of TAGs; # mg KOH needed saponify 1 g oil/fat

Question 40

What is the acid value? The test involves a titration with ___

Answer 40

free f.a. content; KOH

Question 41

a higher molecular weight oil will result in a ___ SV

Answer 41

lower

Question 42

fully saturated lipids have an IV of ___

Answer 42

0

Question 43

what is the smoke point?

Answer 43

temp at which fat/oil produce first visible smoke (200 degrees is min for optimum frying characteristics)

Question 44

what is the flash point?

Answer 44

when oil heated too high, ignites and catches fire

Question 45

what is lipid oxidation?

Answer 45

rxn between oxygen and lipids-->generates peroxides, aldehydes, ketones

Question 46

what determines rate of oxidation?

Answer 46

how quickly e- may be extracted from f.a., leading to free radicals (easier with db bonds)-->light and temp affect

Question 47

what are some ways to prevent lipid oxidation?

Answer 47

reducing PUFAs through hydrogenation and replacement with SA, exclude o2 and light, add antioxidants, create physical barrier (encapsulation)

Question 48

how do antioxidants neutralize free radicals?

Answer 48

by donating one of their own e-

Question 49

Examples of antioxidants include:

Answer 49

BHA, TBHQ, tocopherols, carotenoids, ascorbates, flavonoids

Question 50

what is GRAS status?

Answer 50

generally recognized as safe

Question 51

amount of TFA on label can be labeled as 0g if

Answer 51

0.2

Question 52

what is a replacement for hydrogenation?

Answer 52

modification through fractionation

Question 53

good TFAs that are a family of isomers of octadecdienoic acid (18:2)

Answer 53

CLAs (conjugated linoleic acids)

Question 54

where are CLAs generated? How?

Answer 54

rumen of animals; process of bacterial isomerization

Question 55

positional isomers vs. geometric isomers?

Answer 55

positional: pos. of conjugated db bonds geometric: cis/trans

Question 56

what is the most common CLA isomer (there are 24 in total)?

Answer 56

octadeca-cis-9, trans-11-dienoic acid

Question 57

what are some potential health effects of CLAs?

Answer 57

anticarcinogenic, prevent cardio disease, reduce fat deposit, protect against bone loss

Question 58

what are the physical properties of oils/fats?

Answer 58

crystallization/melting profile, spreadability, texture

Question 59

fats exist in a _______

Answer 59

fat crystal network (aggregated spherulites and non-aggregated forms)

Question 60

>length = ___ MP; cis = __ MP; db bond = ___ MP

Answer 60

>;

Question 61

what are the main functions of fats and oils in foods?

Answer 61

dietary import, flavour/mouthfeel/palatability, cooking medium for heat transfer, food structure, emulsions, baking

Question 62

what are the essential fatty acids? what are the food sources?

Answer 62

alpha linolenic, linoleic; fish/soy/canola/flax/sunflower oils