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FDSC200 > Week4-Course1 > Flashcards

Week4-Course1 Flashcards

1
Q

The inclusion of inferior substances having properties similar to the foods in which they are added is ______

A

Intentional food adulteration

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2
Q

Define food adulteration

A

Food adulteration can be defined as lowering the quality of food by intentional or unintentional substitution of food with some inferior foreign particle or by removal of some value added food substitute from main food item

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3
Q

The simplest strategy to prove adulteration is to demonstrate the presence of a …….

A

Foreign substance

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4
Q

What are the three basic strategies that can be followed to demonstrate adulteration?

A

Demonstrating : 1. Foreign substance

  1. a component is deviated from nomal level
  2. that a profil is unlikely to occur
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5
Q

Electronic microscopy is a _____ method

A

physical

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6
Q

Added water to milk can be detected by measuring milk’s specific gravity. This method is classified as a …… technique for adulteration detection.

A

Physical

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7
Q

Witch method can you use to detect the adulteration of olive oil with hazelnut oil?

A

HPLC

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8
Q

What is the most used technique in the analytical techniques of adulterant

A

HPLC

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9
Q

What is the difference between HPLC and gas chromatography

A

HPLC is used for non-volatile compounds while gas chromatography is used for volatile compounds

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10
Q

Witch of the techniques can be used as a quality control tool because it can separate various chemical constituents from mixtures and that is also used for characterizing food products

A

HPLC

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11
Q

Gas chromatography (GC) is a chemical method that can detect ……… to discriminate among different varieties of the same food product, such as wine.

A

Volatile organic compounds

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12
Q

Name the three techniques that are non-destructives techniques with respect to the sample

A
  1. GC
  2. HPLC
  3. FTIR
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13
Q

…… is a chemical method that can detect milk adulterants.

A

FTIR

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14
Q

…… is a chemical method that can detect an adulterant and it can provide structural identification of the adulterant.

A

NMR (nuclear magnetic resonance)

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15
Q

…… is a molecular method that is used to detect interspecies and varietal adulteration in coffee.

A

real time PCR

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16
Q

Why is RAPD considered unreliable ?

A

Because of the lack of reproducibility

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17
Q

What is the structure level that remains intact throughout denaturation

A

primary structure

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18
Q

Name the phenomena that occurs when proteins form solids or semisoft cloths. Is it reversible?

A

Coagulation. No it is permanent.

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19
Q

Solidification of eggs is due to ___

A

thermally induced denaturation of proteins

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20
Q

Production of foam in beaten egg white is due to _____

A

surface-denatured protein molecules

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21
Q

Production of foam in beaten egg white is due to _____

A

surface-denatured protein molecules. They encapsulate air bubbles

22
Q

What does the coagulation change in the case of proteins?

A

1- changes its physical characteristics
2-alters the ability to bind water (solubility)
3. interferes with biological interactions of enzymes

23
Q

T or F : some denaturated proteins can return to their original states

A

T, example of beaten eggs

24
Q

Name 5 factors that can lead to denaturation

A
  1. temperature change
  2. Mechanical actions
  3. Sound waves and irradiations
  4. pH
  5. exposure to salts, metals or minerals
25
Q

what is the cause of curdling?

A

cold temperatures

26
Q

Why is pH so important in the case of denaturation?

A

Because changes in pH affects the charge the proteins, it may neutralize the charge and proteins will coagulate

27
Q

Among the most important physicochemical properties of proteins in relation to their functional properties are their ____

A

interactions and solubility in water

28
Q

____ charges between two proteins make the coagulation more difficult because of ____

A

similar

electrostatic repulsion

29
Q

Amino acids that are _____ are hydrophilic

A

polar

30
Q

What can be the functional groups in the proteins that are hydrophilic and polar

A 
hydroxyl (OH)
sulfhydryl (SH)
amide (o=c-NH2)
carboxyl (COOH_
amino (NH2)
31
Q

What groups in the proteins are the major contributor of the hydrogen bonds that makes the protein more soluble in water

A

NH (amine) and COOH (carboxyl)

32
Q

Hydrophobic amino acids have ____ or ____ side chains

A

aliphatic

aromatic

33
Q

What is the most important factor determining the functionality of proteins?

A

The solubility in water.

34
Q

What are the three broad classes of proteins

A
  1. Globular (soluble)
  2. Fibrous (insoluble)
  3. Membrane (insoluble)
35
Q

Protein denaturation resulting in exposure of the hydrophobic core decreases solubility and may result in _____

A

protein aggregation (coagulation)

36
Q

The tertiary structure of ___ proteins is fairly spherical

A

globular

37
Q

Name two things that can result in coagulation

A

1- change in net charge (ph)

2- Denaturation that expose the hydrophobic core outside the protein

38
Q

What are the two structure coagulated protein can form

A

1- curds (coagulated mass)

2- gel (entrapping of water in the protein aggregate)

39
Q

A protein molecule that has significant number of amino acids with carboxylic functional groups in their side chains will be:

A

hydrophilic

40
Q

Carboxyl group containing amino acids are more soluble at a pH under ___ because ___

A

4, because the COOH is ionized to COO- and can make a bond with the H in water

41
Q

amine group containing amino acids are more soluble at a pH over ___ because ___

A

10, because NH2 is ionized to NH3+

42
Q

What are the 4 factors you need to analyse in order to know if a specific protein would be of good use in a product

A
  1. degree of water absorption
  2. solubility
  3. viscosity
  4. stability in acids an alkalis (basic) sln
43
Q

What are the functional properties of proteins in food (7)

A
  1. Emulsifying
  2. Meat analog formation
  3. Viscoelasticity
  4. Agents for profuction of flavor/color
  5. thickening agents
  6. Gelling agents
  7. Curd forming
44
Q

What protein gives pigment in muscle (meat)

A

myoglobin

45
Q

What responsible of the brown color in meat

A

prolonged exposure of myoglobin to oxygen

46
Q

Why is the maillard rxn unfavorable from a nutritional perspective in the case of lysine

A

Lysine side chain is NH2, so when it participate in the maillard reaction, the essential amino acid becomes unusable.

47
Q

Does only amino acids that contain an amine side chain like lysine participate in maillard rxn?

A

no, every free amine group can take part in maillard rxn.

48
Q

Does the amine group of attached to the alpha carbon (not of the side chain) can participate in maillard rxn

A

no, because the peptide bonds transform the amino groups into amide groups for all amino acids in the chain expept the last a.a of the chain

49
Q

What are the nutritional contributions of proteins in the human body (6)

A 
1-support growth and repair 
2-fight disease 
3-maintain fluid and mineral balance
4-maintain pH balance
5-control bodily functions
6-provide energy
50
Q

Why does protein is not a good source of energy other than as last resort

A

because of the breakdown causing ammonia and ketones, strainning the kidneys

51
Q

Name example of the function of enzymes in the processing of food and give the enzyme that is associated with the function? (4)

A

1- HFS (amylase and isomerase)
2-meat tenderization (papain: protease)
3-removal of headspace oxygen from food (glucose oxidase)
4-curd formation (rennet)

FDSC200 (23 decks)

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