FATS 1 Flashcards

1
Q

what do the uses of lipids depend on

A

Uses depend on molecule’s chemical configuration: length + degree of unsaturation

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2
Q

whats the major function of fat

A

act as a medium for heat transfer, so to help heat foods without burning

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3
Q

whats shortening powder essential for

A

prep of baked goods (effect depends on fat consistency)

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4
Q

differentiate between solid fats and oils when used as shortening powder

A

solid saturated fats create flakiness and oils create tender crumbly products

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5
Q

how do shortening powders work when cut into fat

A

larger fat particles to melt which leaves behind air pockets (pie crust)

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6
Q

how do shortening powders create air bubbles when creamed into fat

A

air bubbles expand when baked (cookies)

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7
Q

what are emulsions

A

liquid dispersed in another liquid in which it is immiscible

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8
Q

differentiate between oil in water and water in oil emulsions

A

*Oil-in-water (o/w): fat droplets dispersed in water
*Example: milk
*Water-in-oil (w/o): water droplets dispersed in fat
*Example: butter

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9
Q

what are the three parts of emulsions

A
  • dispersed or discontinuous phase
  • dispersion medium or continuous phase
  • an emulsifier: a compound that helps keep one phase dispersed in another (stabilizes)
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10
Q

what does the emulsifier do to the surface tension when it migrates to the interface between phases

A

lowers the surface tension between the dispersed and continuous phases

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11
Q

why can emulsifiers act as a bridge between water and oil

A

b/c they contain both a hydrophilic and hydrophobic region

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12
Q

what are monoglycerides and diglycerides

A

Most frequently used emulsifiers in food industry

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13
Q

what are polysorbate and
propylene glycol

A

Emulsifiers synthesized by food industry

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14
Q

what are phospholipids, proteins, vegetable gums,
dried herbs and spices

A

emulsifiers

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15
Q

what does stability depend on of emulsfcation

A

emulsion’s capacity to
resist separation

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16
Q

describe temporary stability

A

ex: (oil & vinegar dressing)
*Least stable, separate upon standing
*Must be shaken before use

17
Q

describe semi-permenant stability

A

(ex: commercial salad dressings)
*Have added stabilizers to ↓tendency to separate

18
Q

describe permanent stability

A

(ex: mayo)
*Very stable, do not separate

19
Q

what are the 4 things that determine a fat’s melting point

A
  1. Degree of unsaturation
  2. Length
  3. Cis-trans configuration
  4. Crystalline structure
20
Q

how do plant and animal fats degree in degree of saturation + liquid or solid at room temp

A

plant oils typically unsaturated (have double bonds) and liquid at room temp (lower MP)
while animal fats typically saturated and solid at room temp
(higher MP)

21
Q

whats hydrogenation

A

adds hydrogens to the double
bonds of unsaturated fatty acids

22
Q

why does increased chain / carbon length mean higher melting point

A

because more carbon atoms mean more interactions and more
energy required to break them

23
Q

how do cis and trans configuration differ

A

trans configuration have a
higher melting point than cis configuration

24
Q

why do trans configuration have higher melting point than cis

A

because, the better the fat molecules can stack up against each
other, the higher the MP

25
how does crystal structure impact melting point
larger crystals have higher melting point
26
Most fats are polymorphic. what does this mean?
they can exist at more than one crystalline form
27
what are the three crystalline classifications
Alpha (α), beta prime (β’), and beta (β)
28
classify the classifications from least stable to most
alpha , beta prime, beta
29
classify them from highest melting point to lowest
beta, beta prime, alpha
30
whats plasticity
ability of a solid fat to hold its shape but still be moldable
31
what does plasticity determine
spreadability
32
what does plasticity increase with
temperature and degree of unsaturation
33
what are four other functions of fat
flavor, texture, appearance, sateity
34
how does fat influence flavor
help absorb fat soluble flavor compounds
35
how does fat influence texture
causes food to feel more moist
36
how does fat influence appearance
glossy sheen to foods