Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

2) Food Chemistry I > Lipids II > Flashcards

Lipids II Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Gourmet Food flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What is a simple triglyceride? Give examples.

A
  • Triglyceride that only has one type of fatty acid attached to the three positions on the glycerol molecule
  • ex: tristearin, triolein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are mixed triglycerides? How are the names of the fatty acid?

A
  • More than one type of fatty acids
  • Names of fatty acid are run together
  • ex: stearodilinolein, dipalmitolinolenin, palmitostearolinolein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

There are no simple, analytical methods for separating, isolating and identifying individual _________.

A

triglycerides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

If you can’t determine the triglyceride composition, what can you quantify?

A

Determine the overall fatty acid composition of a fat and quantify the relative amounts of the individual fatty acids fairly easily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can you determine the overall fatty acid composition?

A

Through saponification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are FAMEs?

A

Fatty acid methyl esters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is GC analysis? What has it demonstrated?

A
  • Gas chromatography

- Demonstrated that each natural fat source tends to have a relatively consistent fatty acid composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Fats from plant and fish sources tend to be ______

A

Oils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What parts of plants are exceptionally good sources of lipids?

A

Seeds and fruits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In plant seeds, what kind of lipids are used as a source of energy for germination?

A

Triglycerides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are common primary plant sources of edible oils in North America? What are common regional sources?

A
  • Soybean, rapeseed (canola) and peanut

- Olive, coconut, cacao, and palm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Lipids are also obtained as by-products from crops, such as what?

A

Corn and cotton seeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are non-edible oils obtained from plant sources? What are they used for?

A
  • Castor oil, linseed (flax) oil

- Industrial paint/chemical (plasticizer) purposes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How has biotechnology changed linseed oil?

A

Linseed (flax) oil has been transformed to edible Linola

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Can oilseeds be consumed?

A

Yes, can be consumed directly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What kind of fats and oils are much more valuable and useful commercially for margarine manufacture, and for the preparation of salad dressings?

A

Extracted and processed fats and oils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How are animal sources of fat obtained?

A

Fat rendered as a by-product of meat production, produced from the trimmings and the carcasses of cattle, hogs, and sheep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is cream obtained?

A
  • Fat separated from the milk of ruminants, especially cows

- In other parts of the world, other ruminants are important sources of milk fat (water buffalo)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are good sources of fish fat? Where are fish oils used in the world?

A
  • Fatty fish (sardines, herring, menhaden)

- Used extensively in Europe, less so in North America

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What technique determines the fatty acid composition/distribution? How can its characterization be used?

A
  • Gas chromatography
  • Characterizing fats and oils to classify them into various characteristic groups (classifying major sources, has limitations)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the seven classifications of fats by group characteristics determined by GC?

A

1) Milkfat
2) Lauric Acid
3) Oleic-linoleic
4) Linolenic
5) Animal fat depot
6) Marine oil
7) Erucic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What type of fat does the milkfat group contain?

A

Includes fats from the milk of lactating ruminants (cow, goat, yak, sheep, water buffalo)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the distinguishing features of the milkfat group?

A
  • High levels of long-chain saturated fatty acids

- Unique and substantial portion of short chain (< C12) fatty acids, butyric acid (C4:0)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What kind of lipids are responsible for a bad “rancid-like” odor when released from the triglyceride by lipolysis?

A

Short-chain fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the general fatty acid composition for cows’ milk fat?

A
  • 25-32% palmitic acid, C16
  • 10-12% stearic acid, C18
  • 30-40% oleic acid, C18:1
  • 4-15% butyric acid and other short-chain fatty acids (up to C10)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Do cows’ milk fat contain trans forms of their unsaturated fatty acids? If so, why?

A
  • Yes

- Due to (bio)hydrogenation in the rumen by microorganisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What lipid is responsible in part for the desirable flavour of aged cheese?

A

Short-chain fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What does biotechnology use to speed up the maturation of cheese and enhance cheese flavour?

A

Microbial lipases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the major uses of the milkfat group?

A

Production of butter (water-in-oil without emulsion) as a spread and as a cooking fat (ghee)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How many carbons does the lauric acid group contain?

A

12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the sources of the lauric acid group?

A
  • Oil palm (tropical oils)

- Palm kernal oil, coconut and babasu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How does palm kernal oil differ from palm oil?

A
  • Palm kernal oil (extracted from palm oilseeds)

- Palm oil (from palm fruit), which is much more highly unsaturated and is not part of the lauric acid group

33
Q

Is palm oil a part of the lauric acid group?

A

No

34
Q

What are the distinguishing characteristics of the lauric acid group?

A
  • High content of lauric acid (C12)

- Which can account for 40-50% of the total fatty acid content

35
Q

Are most of the fatty acids in lauric acids unsaturated or saturated?

A
  • Most are saturated

- Only small amounts of unsaturated fatty acids are present

36
Q

Are lauric acids solid or liquid at room temperature?

A
  • Although largely saturated

- They are oils owing to the high proportion of C12 fatty acids in their triglycerides

37
Q

What kind of fatty acids are resistant to oxidative rancidity? Which group is an example of this?

A
  • Low degree of unsaturation

- Lauric acid

38
Q

How can lauric acids produce distinct fat and oil fractions?

A

Can be fractionally crystallized (fractionated)

39
Q

Palm and palm kernal oils are highly valued oils. How are they mostly used?

A

Oil or fat in baked gods which need a long oxidative shelf life

40
Q

The bulk of our common oils fall into which group? Give examples.

A
  • Oleic-linoleic acid

- Cottonseed, sunflower, safflower, olive, peanut, corn oil

41
Q

Saturated fatty acids make up ______% of the total fatty acid composition in the oleic-linoleic group.

A

<20%

42
Q

What are the predominant fatty acids in the oleic-inoleic group?

A
  • Long chains
  • Oleic (C18:1)
  • Linoleic (C18:2)
43
Q

Oleic-Linoleic acids have negligible amounts of C18:3. What is the consequence?

A

The oils in this category do not suffer from reversion and are relatively stable

44
Q

How can oleic-linoleic acids be turned into plastic edible fats? Give an example.

A

Partial hydrogenation (shortenings)

45
Q

What fatty acids do the Linolenic acid group contain?

A
  • Significant linolenic acid
  • C18:3
  • In conjunction with oleic and linoleic acids
46
Q 
The linolenic acid group is high in: 
A) Saturated fatty acids
B) Trans fatty acids
C) Monounsaturated fatty acids
D) Polyunsaturated fatty acids
A

Polyunsaturated fatty acids

47
Q

Which group is particularly reactive and readily oxidized?

A

Linolenic acid

48
Q

Most oils in this group tend to be categorized as industrial “drying oils”. Which group does this passage refer to?

A

Linolenic acid

49
Q

Why are linolenic acids sometimes referred as “drying oils”?

A

Because of their ability to polymerize into a hard film if applied as a thin layer on surfaces (paint)

50
Q

The polymerization capability is present in all _____________ oils, but those containing high levels of _____________ are more reactive

A

unsaturated oils, linolenic acid

51
Q

What are common examples of the linolenic acid group?

A

Soybean, linseed, castor, hempseed and perilla oils

52
Q

What was soybean oil used for originally? What is it used for nowadays? What led to this conversion?

A
  • Originally: industrial drying oil
  • Nowadays: predominantly as an edible oil
  • Application of food technology and plant breeding
53
Q

Processed soybean oil, if stored after extraction without modification, suffers from a problem commonly termed _______.

A

Reversion

54
Q

What is reversion?

A

Relatively rapid transition from a bland, tasteless oil shortly after processing to a grassy, hay-like and then fishy flavour

55
Q

How is reversion overcome? What fats are converted to what?

A

By hydrogenation to convert a substantial portion of linolenic to oleic and linoleic acids

56
Q

What fat is an essential omega-3 fatty acid?

A

Linolenic acid

57
Q

What are the sources of the animal fat depot group?

A

Lard from pigs, tallow from sheep and cattle

58
Q

What are the characteristics of the animal fat depot group? How is their melting point? How do they compare to oleic-linoleic acids?

A
  • Relatively high melting point

- Yet, contain similar levels of unsaturated fatty acids as the oils in the oleic-linoleic acid group

59
Q

What is the animal fat depot group composed of?

A
  • 50-60% oleic and linoleic acid

- 30-40% palmitic and stearic acid

60
Q

Why are animal fat depot lipids fats rather than oils?

A

Due to a selective fatty acid distribution on the glycerol backbone which influences the overall physical properties on the lipid

61
Q

Animal fat depot group has a higher ratio of what compared to the oleic-linoleic acid group?

A

Di-saturated (gs2u) and tri-saturated (gs3) glycerides

62
Q

Compare GS2U and GS3 of beef tallow and peanut oil.

A

Beef tallow: 12% GS3, 44% GS2U

Peanut oil: 0.1% GS3, 10% GS2U

63
Q

The presence of relatively high amounts of ____ can change the physical characteristics of the lipid system from an oil to a fat.

A

GS3

64
Q

The fatty acid distribution can have a strong influence on the plasticity and predominance of specific ______ forms in a fat; affecting its funcitonality.

A

crystal forms

65
Q

What are the sources of the marine oil group? What are they a rich source of?

A
  • Fish oils

- Rich source of omega-3 fatty acids

66
Q

What are the characteristics of the marine oil group?

A
  • Contain low levels of saturated fatty acids

- High in long-chain unsaturated fatty acids (C16-C22)

67
Q

Some fish oil fatty acids can be highly unsaturated. Up to how many double bonds do they contain?

A

Up to 6 double bonds

68
Q

Why do marine oils possess their own particular processing problems? What do they suffer from? What are they susceptible to?

A

Due to their very high degree of unsaturation

- Suffer from reversion, and are susceptible to autoxidation

69
Q

How are processed fish oils used in Europe?

A

Extensively for margarine and shortening production

70
Q

What are two examples of the erucic acid group?

A

Rapeseed oil and mustard oil

71
Q

How was rapeseed oil used originally?

A

Used extensively as a marine motor oil

72
Q

Why does the erucic acid group have excellent lubricating properties?

A

Due to its high erucic (C22:1) acid content

73
Q

Natural rapeseed oil contains __%-__% erucic acid, which is considered a health hazard. Why?

A
  • 40-50%

- Infuses into the heart muscle in rats

74
Q

What is canola oil? How is it produced?

A

Indigenous rapeseed has been converted by plant breeding to a variety which produces a low erucic acid edible oil

75
Q

Canola oil, which is a low erucic acid edible oil, contains similar properties to which oil?

A

To oleic-linoleic acid oils

76
Q

What are high-erucic oils being used as now?

A

Biodegradable lubricants

77
Q

What kind of canola oils can now be produced thanks to genetic engineering?

A

Lauric acid canola oils

78
Q

How will we custom engineer oils in the future?

A
  • Control fatty acid composition and distribution genetically in plants
  • To custom engineer oils with properties which are desirable

2) Food Chemistry I (31 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions