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Food Science Exam 4 > Colorants > Flashcards

Colorants Flashcards

(60 cards)

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1
Q

What are the fat soluble vitamins?

A

A, D, E, K

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2
Q

What are the water soluble vitamins?

A

B group, C

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3
Q

What is the active form of vitamin D?

A

1,25-dihydroxycholecalciferol

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4
Q

What factors affect the stability of vitamin D?

A

Light, oxidation, and alkali

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5
Q

What happens to cholecalciferol added to skim milk after 12 days of exposure to fluorescent light at 4°C?

A

Half is lost

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6
Q

List the major groups of food colorants.

A

Inorganic, Organic, Synthetic

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7
Q

What is the source of color in food?

A

Light (electromagnetic waves)

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8
Q

What is the wavelength range of visible light?

A

380-770 nm

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9
Q

What do objects do to produce color?

A

Reflect or transmit light of specific wavelength

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10
Q

How do observers detect color signals?

A

Using the retina: rod-achromatic, cones-color

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11
Q

What is trichromatic vision?

A

Vision based on three types of cones sensitive to blue, green, and red

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12
Q

Why is color important in food?

A

Indicator of food quality and visual attraction

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13
Q

What are the properties of inorganic colorants?

A

Often contain transition metals and have partially filled d orbitals

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14
Q

What is iron oxide used for in food?

A

Provides a wide range of colors based on its form

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15
Q

What is titanium dioxide classified as by the International Agency for Research on Cancer?

A

Group 2B carcinogen

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16
Q

What is calcium carbonate used for?

A

In hard and soft candies and mints

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17
Q

What are organic colorants characterized by?

A

Conjugated systems that absorb light

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18
Q

What are phenolics?

A

Compounds with one or more hydroxyl groups attached to a benzene ring

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19
Q

What are tannins?

A

Water-soluble high molecular weight compounds that can precipitate proteins

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20
Q

What are the two types of tannins?

A

Hydrolyzable tannins, Condensed tannins

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21
Q

What color range do tannins exhibit?

A

Yellow to brown

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22
Q

What affects the color of tannins?

A

pH sensitivity

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23
Q

What are flavonoids?

A

Compounds widespread in the plant kingdom, usually pale in color

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24
Q

What are anthocyanins?

A

Glycosylated forms of anthocyanidins, more stable than the aglycone

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25
What factors affect phenolic color?
pH and polyphenol oxidases
26
What is enzymatic browning?
The oxidation of phenols to quinones, leading to dark pigments
27
How can enzymatic browning be inhibited?
Using Cu2+, blanching, low pH, chelation of copper, reducing agents
28
What is the role of chlorophyll in plants?
Photosynthesis and photoprotection
29
What are the two main types of chlorophyll?
Chlorophyll a and Chlorophyll b
30
What is the significance of heme pigments?
They are responsible for meat color
31
What is phycocyanin?
A pigment-protein complex found in cyanobacteria
32
What is the definition of a food color additive?
Any dye, pigment, or substance that imparts color when added to food
33
What regulates the use of color additives in the U.S.?
The Federal Food, Drug and Cosmetic Act (FD&C)
34
What is the difference between certified and exempt colorants?
Certified colorants are synthetic dyes regulated by the FDA; exempt colorants are natural pigments or synthetic colorants that are nature identical
35
What are the two forms of carotenoids?
Carotene (hydrocarbon) and Xanthophyll (oxygenated hydrocarbon)
36
What is β-Carotene a precursor of?
Vitamin A
37
What is unique about betalains?
They are nitrogen-containing pigments that do not co-exist with anthocyanins
38
What is the color stability range of betalains?
pH 3-7
39
What is the effect of heat on betalains?
They are susceptible to heat
40
What are the primary food sources of lycopene?
Tomatoes, watermelon, red peppers, pink grapefruit, strawberries, guava
41
What does the term 'chromophore' refer to in organic colorants?
The part of a molecule responsible for its color
42
What act regulates certified colorants in the U.S.?
U.S. Food, Drug and Cosmetic Act of 1938 ## Footnote This act established the regulation of color additives in foods.
43
What must foods containing certified colorants be labeled as?
Color added ## Footnote This labeling is required by the FDA for foods with synthetic dyes.
44
What are exempt colorants?
Natural pigments or synthetic colorants that are nature identical ## Footnote These colorants do not require the same labeling as certified colorants.
45
What does the Nutrition Labeling and Education Act of 1990 require?
Mandatory listing of all colorants (both certified and exempt) ## Footnote This ensures transparency in food labeling regarding color additives.
46
Define 'colorants'.
General term for any color additive ## Footnote This includes both dyes and pigments.
47
What is a dye?
A water-soluble powder ## Footnote Dyes are often used in food products for coloring purposes.
48
What is a lake in terms of color additives?
Lakes are bound to a chemical substrate to produce an insoluble product ## Footnote Lakes are often used in oil-based foods.
49
Define 'pigment'.
Insoluble colorants ## Footnote Pigments do not dissolve in water and are used in various applications.
50
How many certified colors are allowed in food?
Only 9 ## Footnote These include FD&C colors, which are specifically regulated.
51
What is Citrus Red #2 used for?
Only on the surface of whole fruit or sausages ## Footnote This is one of the certified colors permitted for use.
52
What process transforms water-soluble FD&C colorants into lakes?
Precipitation with Al, Ca, or Mg salts on a substrate of Al(OH)3 ## Footnote This process creates a water-insoluble powder.
53
What are the benefits of using lakes in food products?
More stable to heat and light, do not 'bleed' or migrate ## Footnote Lakes are particularly useful in oil-based or low-water content foods.
54
What is carmine derived from?
The pigment carminic acid from cochineal ## Footnote Carmine is a natural colorant used in various food products.
55
What is structural color?
Color produced by microscopic structures rather than pigments ## Footnote Examples include colors seen in frogs and Anna's hummingbirds.
56
What is the L*a*b* color model?
Standard in the food industry for color measurement ## Footnote It provides a way to quantify colors based on human vision.
57
Which food is lighter in color? A. L* = 80, a* = 10, b* = 5 or B. L* = 50, a* = -3, b* = 12?
A ## Footnote Higher L* values indicate lighter colors in the L*a*b* color space.
58
What does spectrophotometry measure?
Reflection or transmission properties of a material as a function of wavelength ## Footnote It is a key technique in color analysis.
59
What is the Beer-Lambert law equation?
A = ε × l × c ## Footnote This law relates absorbance to concentration and path length.
60
In the Beer-Lambert law, what does 'c' represent?
Concentration (M) ## Footnote It is measured in molarity.

Food Science Exam 4 (2 decks)

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