Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

2) Food Chemistry I > Lipids VIII > Flashcards

Lipids VIII Flashcards

(68 cards)

Start Studying
1
Q

What is the % of TG in milk fat?

A

96%

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

Why are sterols necessary in milk fat?

A

To maintain the fluidity of phospholipids

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

What are the main fatty acids in milk fat? (3)

A
  • Oleic
  • Stearic
  • Palmitic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How much linoleic and linolenic does milk fat contain?

A

Very little

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

Which product contains butyrate? What is the chemical abbreviation?

A

Milk fat (C4:0)

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

In milk fat, long chain fatty acids are preferred in which positions?

A
  • sn-1

- sn-2

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

In milk fat, short-chain fatty acids are preferred in which positions?

A

sn-3

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

What kind of TG are preferentially synthesized in milk fats?

A

TG with one short and two long-chain FA

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

How does the ratio of saturated to unsaturated FA vary in milk?

A
  • Does not vary

- Due to their typical diet

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

TG are contained within ___________ that are surrounded by a _________

A
  • fat globules

- membrane

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

_________ are synthesized by the microflora of the cow, and present health benefits

A

Conjugated linoleic acid (CLAs)

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

What are the components of the membrane that surround the fat globules in milk fats?

A
  • Protein (41%)
  • Phospholipids and glycolipids (30%)
  • Cholesterol (2%)
  • Neutral glycerides (14%)
  • Water (13%)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How much cholesterol does milk, shrimp, and eggs contain?

A
  • Milk: 27 mg
  • Shrimp: 125 mg
  • Eggs: 275 mg
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the membrane that surrounds the fat globules in milk contain?

A
  • Double layer of lipoproteins

- Enzymes, including lipase

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

What is the function of the membrane of the fat globule

A

Prevents lipolysis

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

What is the consequence of the disruption of the membrane of fat globules? In which situation could this happen?

A
  • Homogenization of milk
  • Allows lipase to bind to the fat globules and to hydrolyze TG at a high rate
  • Milk becomes unpalatable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What must be done prior to homogenization? Why?

A

Lipases must be inactivated by pasteurization to avoid them hydrolyzing the TG

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

What is lactose degraded to during ripening? How?

A

Degraded to lactic acid by homofermentation

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

What does the type and extent of milk fat degradation depend on?

A

Depends on the microflora

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

What is a prerequisite for good aroma in cheese? What are the exceptions?

A
  • As little lipolysis as possible

- Exceptions: stinky cheeses (ex: roquefort)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

More/less free fatty acids are released in homogenized milk than untreated milk.

A

More

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

What do the different aromas of various types of cheeses arise from?

A
  • From the different specificities of the lipases involved

- They exhibit specificity to hydrolyze certain substrates, which causes different aromas

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

Are the levels of saturated or unsaturated FA higher in red meat?

A

Unsaturated exceeds saturated

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

If the levels of unsaturated FA exceeds saturated FA in red meat, why are the lipid products solid?

A

Since they have more fully saturated fatty acids (GS3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the % of total saturated lipids in red meat? Which fatty acids are the most present?
- Total: 46% | - Palmitic (16:0) > Stearic (18:0) > Myristic (14:0)
26
What is the % of total monounsaturated lipids in red meat? Which fatty acids are the most present?
- Total: 50% | - Oleic (18:1) > Palmitoleic (16:1)
27
What is the function of cholesterol in red meat? How much is found in 100 grams?
- Integral component of cellular membranes | - 70-90mg/100 grams
28
What is the main monounsaturated fatty acids found in skeletal muscles of red meat?
- Oleic acid (90% of MUFAs) | - 45% of total FA
29
What is the main polyunsaturated fatty acids found in skeletal muscles of red meat? What is the main source of saturated? What is the main source of unsaturated?
- Polyunsaturated: Linoleic acid - Monounsaturated: Oleic acid - Saturated: Palmitic and stearic acid (2:1 ratio)
30
What is the main saturated fatty acids found in skeletal muscles of red meat?
- Palmitic acid and stearic acid in a ratio of 2:1 (90%) | - 40% of total FA
31
How many eggs do hens produce per year?
225
32
What is the composition of the albumen of an egg?
10% protein, 0.03% lipids
33
What is the composition of the yolk of an egg?
16% protein, 35% lipids
34
What is the composition of the whole egg?
13% protein, 11% lipids
35
Why are eggs nutrient rich?
Complete protein, essential FAs, vitamin D
36
What is moderate egg consumption?
6 eggs/week does not increase coronary heart disease
37
What is the macronutrient composition of an egg yolk?
- Water: 48.7% - Fat: 32.9% - Protein: 16.4%
38
Are egg yolks water-soluble?
Yes, even if they behave as lipids, eggs are "soluble" and can readily disperse in water
39
Why can eggs readily "disperse" in water?
- High lipid content - High proportion of phospholipids - More than 90% of the lipids in the yolk are associated with lipoproteins
40
What is the ratio of LDL to HDL in egg yolks?
LDL: 68% HDL: 14%
41
What does cholesterol provide in egg yolks?
Flexibility
42
How does the density of LDL and HDL compare?
LDL: 0.98 HDL: >1.0
43
How does the composition of LDL compare to HDL?
LDL: large amounts of lipids (85%); mostly TG (69%) and phospholipids (26%) HDL: small amounts of lipids (20%); mostly phospholipids (60%) and TG (40%)
44
Where are LDL particles present in egg yolk? In what form?
In the form of tiny micelles suspended in the plasma fraction
45
Does LDL or HDL contain phosvitin? What is it?
- HDL | - Phosphorus-rich, lipid-free protein
46
Associate these words: 1) LDL 2) HDL A) Lipovitellin B) Lipovitellenin
LDL: Lipovitellenin HDL: Lipovitellin
47
What influences the fatty acid composition of an egg yolk?
The breed and the diet
48
What is the lipid composition in egg yolks?
- TG (66%) - Phospholipids (28%) - Cholesterol (5%)
49
What is the fatty acid composition of egg yolks?
- Saturated FA: 30-35% - MUFAs: 40-45% - PUFAs: 20-25%
50
What happens when the dietary PUFA is elevated in egg yolk?
Linoleic acid increases and oleic acid decreases
51
What are the three main components of egg yolk phospholipids?
- Phosphatidylcholine/Lecithin (73%) - Phosphatidylethanolamine/Cephalin (15%) - Lysophosphatidylcholine (6%)
52
What is lysophosphatidylcholine?
- Derivative of phosphatidylcholine | - One of the FA has been replaced by a hydroxyl group
53
What are the deteriorative changes that occur in dried whole egg and egg yolk related to?
Maillard reaction
54
What leads to discoloration of dried whole egg and loss of palatability?
The reaction between cephalin and glucose (Maillard)
55
How is the development of off-flavour during storage eliminated in eggs?
- Elimination of glucose | - Addition of glucose oxidase followed by catalase
56
What are designer eggs?
- Enhance the image of eggs as healthy and nutritional | - Omega-3 fatty acids eggs (feeding hens flax or fish oil); darker yellow colour to the yolk
57
What is the fat content of fish depend on?
- Species of fish - Maturity - Season - Food availability - Feeding habit
58
Where does fat deposition occur in fish?
Muscle tissue, liver, intestines
59
Fish is an important contributor to what types of omega-3 fatty acids? What are the benefits and downsides?
- Omega-3-polyenic acids (5 or 6 double bonds) - Nutritional value - Preservation is difficult because of their easy peroxidation
60
What is the typical fatty acid profile of fish oil?
- Saturated (28%) - Unsaturated (28%) - Polyunsaturated (38%)
61
What is the % of TG in soybeans? What about phospholipids?
- TG (96%) | - Phospholipids (2%)
62
What is the fatty acid profile of soybean oil?
- Saturated FA (14%) | - Unsaturated FA (81%)
63
What is the main saturated FA in soybean oil? What are the main unsaturated FA in soybean oil?
- Palmitic acid (10%) - Linoleic acid (51%) - Oleic acid (23%)
64
When are lecithins removed in the processing of oil? Why?
- Removed from degumming | - To use their emulsifying power for other means
65
What are the unsaponifiables contained in soybean oil? When are they removed?
- Mostly tocopherol and sterols | - Partially removed in deodorization
66
When are free fatty acids and pigments removed from soybean oil?
Refining and bleaching
67
Why are soybean oils classified as semi-drying oils?
Due to their high linoleic and linolenic acid content
68
What is responsible for the stronger tendency of soybean oil to undergo oxidative phosphorylation?
Linolenic acid

2) Food Chemistry I (31 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions