U4 - a + b

Question 1

properties of a fat are a function of…

Answer 1

1. fatty acid composition

2. fatty acid distribution

Question 2

difference and similarity between lard and vegetable oil

Answer 2

similar fatty acid content
different distribution, causing lard to be solid
due to configurations of GS3 and GS2U in lard

Question 3

characteristic of lard texture

Answer 3

grainy. fixed by interesterification

Question 4

what is G2SU

Answer 4

glyceride with 2 saturated and 1 unsaturated fatty acid

oleopalmitostearin. forms large crystals and causes a grainy texture

Question 5

when is crystal modified lard formed (CML)

Answer 5

intraesterification conditions

Question 6

when is partially modified lard (PML) formed

Answer 6

random distribution conditions

Question 7

when is direct interesterified lard (DIL) formed

Answer 7

directed interesterification (GS3)

Question 8

what is interesterification

Answer 8

exchange of fatty acids on the glycerol backbone via heat and a catalyst. occurs between triglycerides

Question 9

potential catalysts for interesterification

Answer 9

tin, lead, zinc, alkali earth metals

Question 10

difference between interesterification and hydrogenation

Answer 10

both change the physical and chemical properties of the lipid, but interesterification doesn’t produce trans fats

Question 11

interesterification v intraesterification

Answer 11

inter - between TGs

intra - within a TG

Question 12

what happens when interesterification is undergone at lower temperatures ?

Answer 12

more saturated long-chain glycerides fractionally crystallize out

Question 13

random esterification

Answer 13

interesterification carried out to equilibrium, assuming random distribution. occurs at low temperatures

Question 14

directed interesterification

Answer 14

interesterification is directed away from its usual random end-point, allowing the fat to crystallize (GS3 crystallizes first)

Question 15

is chemical interesterification random or directed?

Answer 15

random

Question 16

is enzymatic interesterification random or directed?

Answer 16

directed - produces lipids with highly specific compositions for functional uses and mono/diglycerides for emulsifiers

Question 17

catalyst used at high temperature

Answer 17

KOH and NaOH

Question 18

catalyst used at low temperature

Answer 18

NaOCH3

Question 19

cocoa butter melting point

Answer 19

sharp and at body temp

Question 20

can other fats and oils be modified to produce cocoa butter?

Answer 20

yes! good because this reduces the amount of expensive cocoa butter needed

Question 21

what can be formed as a byproduct from interesterification

Answer 21

mono and di glycerides used as emulsifiers

Question 22

4 analytical methods for modified triglycerides

Answer 22

Iodine value
saponification value
gas chromatographic analysis
liquid chromatogroaphy

Question 23

definition of iodine value

Answer 23

mass of iodine in g absorbed by 100g of a fat sample

Question 24

what 2 things does IV tell us

Answer 24

degree of unsaturation and source of oil

Question 25

IV is directly proportional with...

Answer 25

degree of unsaturation fats are lower oils are higher

Question 26

IV is indirectly proportional with...

Answer 26

melting point

Question 27

description of WIJS method

Answer 27

1. ICl + fat --> saturated 2. KI + ICl excess --> I2 3. I2 titrated with NaSO3 4. blank titration

Question 28

how to calculate IV

Answer 28

create a ratio between the grams of iodine needed for 1 molecule of fat (taking # double bonds into account)

Question 29

catalyst activity is represented as

Answer 29

decrease in IV per time

Question 30

relationship between agitation and hydrogenation

Answer 30

more agitation = faster hydrogenation

Question 31

relationship between catalyst concentration and hydrogenation

Answer 31

more catalyst = faster hydrogenation

Question 32

what is saponification

Answer 32

hydrolysis of ester under alkaline conditions

Question 33

what is saponification value

Answer 33

mg of KOH needed to neutralize the FAs released from hydrolyzing 1g of lipid

Question 34

saponification value equation

Answer 34

(56.1 * (B-S) * N)/g

Question 35

saponification is directly proportional to

Answer 35

number of fatty acids

Question 36

saponification value is indirectly proportional to

Answer 36

chain length

Question 37

method for gas chromatography

Answer 37

1. extract 2. saponify 3. prepare methyl ester 4. chromatograph methyl esters 5. determine peak areas of fatty acids (retention time) 6. compare to the response curve of known fatty acids

Question 38

G2SU means… a. TG with 2 unsaturated fatty acids and one saturated fatty acid b. TG with 2 short chained fatty acids and one unsaturated fatty acid c. TG with 2 saturated fatty acids and 1 unsaturated fatty acid

Answer 38

c

Question 39

True or false | Intraesterification is an exchange of FAs among TG molecules

Answer 39

F

Question 40

the mass of iodine in grams absorbed by 100g of the sample is…

Answer 40

iodine value

Question 41

the saponification value of a fat is inversely proportional to the…

Answer 41

chain length

Question 42

The saponification value of a fat sample is a. Directly proportional to the chain length of fatty acids in the sample b. Inversely proportional to the chain length of fatty acids in the sample c. Directly proportional to the number of double bonds in the sample d. Inversely proportional to the number of double bonds in the sample

Answer 42

b

Question 43

the rate of hydrogenation reaction is measured by the change of… a. Saponification value per minute b. Chain length per minute c. IV per minute

Answer 43

c

Question 44

why don't fats have sharp melting points

Answer 44

complex mix of TGs with unique melting points. composite of these MPs

Question 45

why do fats appear solid at room temperature

Answer 45

oil trapped in a crystalline matrix

Question 46

what % of solids are neccessary to make the fat retain solid character

Answer 46

10%

Question 47

what is plasticity

Answer 47

changes in consistency as a function of temperature

Question 48

what property of fats allows them to have plasticity

Answer 48

made of a liquid in a crystalline matrix. thus, the 3D crystal network is held together by weak VDW interactions that constantly dissociate and reform

Question 49

solid-to-liquid ratio is a function of

Answer 49

temperature

Question 50

plasticity of a function of

Answer 50

solid to liquid ratio

Question 51

what is the plastic range

Answer 51

the state a fat is in when it can be deformed readily

Question 52

the plastic range is a function of (2 things)

Answer 52

fatty acid composition and distribution

Question 53

difference between margarine and butter

Answer 53

margarine - wide plastic range. butter - small plastic range

Question 54

what is polymorphism

Answer 54

TGs able to change from one crystal form into another

Question 55

alpha form

Answer 55

thin,leaf-like crystals melting fat the quickly cooling random packing arrangement unstable

Question 56

beta prime form

Answer 56

remelting and slowly cooling small and uniform crystals desirable structure

Question 57

beta form

Answer 57

remelting and cooling very slowly dense, large crystals large and grainy

Question 58

analytical methods for studying polymorphism

Answer 58

x-ray diffraction analysis microscopic analysis IR spectroscopic analysis thermal analysis

Question 59

how to determine solid fat content

Answer 59

dilatometry

Question 60

what is dilatometry

Answer 60

measurement of the change in specific volume per unit of temperature change

Question 61

dilatometry process

Answer 61

measuring the fat expansion as a function of temperature in a reservoir

Question 62

dilatometry curve is a combination of what 3 curves

Answer 62

1. thermal expansion of solid fat 2. expansion due to change in state 3. thermal expansion of liquid only these 3 are consecutive

Question 63

solid fat index formula

Answer 63

x/y * 100 (x is at a certain temperature)

Question 64

how to determine solid fat content

Answer 64

NMR - nuclear magnetic resonance

Question 65

NMR process

Answer 65

1. place fat in magnetic field 2. radiofrequency (RF) pulse delivered perpendicular to field 3. the H nuclei spins 4. detect free induction decay (FID) - relaxiation process . since solids relax faster than liquids, comparing the FID time determines the SFC

Question 66

what method is preferred? NMR or dilatometry

Answer 66

NMR

Question 67

consitstency

Answer 67

apparent hardness at a specific temperature

Question 68

beta prime in shortening

Answer 68

``` large amount of small air bubbles. smaller crystals whiter, creamier, more tender, smoother uniform and glossy better volume and texture of baked goods ```

Question 69

beta in shortening

Answer 69

small amounts of large air bubbles large clustered crystals waxy/grainy

Question 70

what crystals are present in natural lard? rearranged? how does the molecular arrangement change

Answer 70

natural - beta. more palmatic acid at postion 2 | rearranged - beta prime

Question 71

what kind of mixture is margarine

Answer 71

water-in-oil emulsion

Question 72

what oils are present in margarine

Answer 72

soybean (beta) and hydrogenated cottonseed (beta prime)

Question 73

blending these 2 oils into margarine is desirable because...

Answer 73

produces a high polyunsaturated and low/none trans containing product. good spreadability and high temp stability

Question 74

what is tempering

Answer 74

process of transforming to the proper polymorphic form

Question 75

what must processors be mindful of when tempering?

Answer 75

removing the heat of transformation so that melting and over-transforming dont occur

Question 76

difference between hydrogenated palm kernel oil and randomized hydrogenated palm kernal oil. result of mixing

Answer 76

hydrogenated palm kernel oil - hard butter; melts at a higher temp; waxy mouthfeel randomized hydrogenated palm kernal oil - melts at a lower temp mixing creates a hard butter that melts in your mouth

Question 77

cocoa butter

Answer 77

short melting range mostly disaturated TGs polymorphism state determines texture at temperatures

Question 78

small beta crystals in cocoa butter

Answer 78

glossy texture. beta prime

Question 79

large, clustered beta crystals

Answer 79

chocolate bloom. white spots and dull surface appearance

Question 80

2 examples of oil-in-water emulsions

Answer 80

mayo and salad dressing

Question 81

what properties do emulsions have in food products

Answer 81

more viscous more opaque fatty sensation masked

Question 82

True or false: fat can provide the body with vitamin C

Answer 82

false

Question 83

a crunchy chocolate is obtained when cocoa butter forms a. Small alpha crystals b. Small beta prime crystals c. Small beta crystals d. Large beta crystals

Answer 83

c

Question 84

butter has a sharp fat content curve which means a. It melts quickly b. It releases flavors quickly c. None d. Both

Answer 84

d

Question 85

The preferred crystal type in margarine is… a. Alpha crystals because it gives better spreadability b. Beta prime crystals because it give better spreadability and creamy mouthfeel c. Beta crystals because they give a desirable degree of solidness

Answer 85

b

Question 86

fats don’t have sharp melting points because a. Consist of different TGs with different MPs b. Have a 3D network of crystals delaying the melting of some fat crystals c. None d. Both

Answer 86

a

Question 87

Interesterified TGs can be fractionated by controlling the …

Answer 87

temp

Question 88

The change in consistency as a function of temperature is…

Answer 88

plasticity

Question 89

True or false: Beta prime crystals are preferred for chocolate

Answer 89

false; beta

Question 90

The technique that is based on the measurement of the change in specific volume per unit temperature is called…

Answer 90

dilatometry

Question 91

When fat is cooled quickly it forms thin, leaf-like crystals. This forms…

Answer 91

alpha crystals