FATS 1 Flashcards
what do the uses of lipids depend on
Uses depend on molecule’s chemical configuration: length + degree of unsaturation
whats the major function of fat
act as a medium for heat transfer, so to help heat foods without burning
whats shortening powder essential for
prep of baked goods (effect depends on fat consistency)
differentiate between solid fats and oils when used as shortening powder
solid saturated fats create flakiness and oils create tender crumbly products
how do shortening powders work when cut into fat
larger fat particles to melt which leaves behind air pockets (pie crust)
how do shortening powders create air bubbles when creamed into fat
air bubbles expand when baked (cookies)
what are emulsions
liquid dispersed in another liquid in which it is immiscible
differentiate between oil in water and water in oil emulsions
*Oil-in-water (o/w): fat droplets dispersed in water
*Example: milk
*Water-in-oil (w/o): water droplets dispersed in fat
*Example: butter
what are the three parts of emulsions
- dispersed or discontinuous phase
- dispersion medium or continuous phase
- an emulsifier: a compound that helps keep one phase dispersed in another (stabilizes)
what does the emulsifier do to the surface tension when it migrates to the interface between phases
lowers the surface tension between the dispersed and continuous phases
why can emulsifiers act as a bridge between water and oil
b/c they contain both a hydrophilic and hydrophobic region
what are monoglycerides and diglycerides
Most frequently used emulsifiers in food industry
what are polysorbate and
propylene glycol
Emulsifiers synthesized by food industry
what are phospholipids, proteins, vegetable gums,
dried herbs and spices
emulsifiers
what does stability depend on of emulsfcation
emulsion’s capacity to
resist separation
describe temporary stability
ex: (oil & vinegar dressing)
*Least stable, separate upon standing
*Must be shaken before use
describe semi-permenant stability
(ex: commercial salad dressings)
*Have added stabilizers to ↓tendency to separate
describe permanent stability
(ex: mayo)
*Very stable, do not separate
what are the 4 things that determine a fat’s melting point
- Degree of unsaturation
- Length
- Cis-trans configuration
- Crystalline structure
how do plant and animal fats degree in degree of saturation + liquid or solid at room temp
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)
whats hydrogenation
adds hydrogens to the double
bonds of unsaturated fatty acids
why does increased chain / carbon length mean higher melting point
because more carbon atoms mean more interactions and more
energy required to break them
how do cis and trans configuration differ
trans configuration have a
higher melting point than cis configuration
why do trans configuration have higher melting point than cis
because, the better the fat molecules can stack up against each
other, the higher the MP
how does crystal structure impact melting point
larger crystals have higher melting point
Most fats are polymorphic. what does this mean?
they can exist at more than one crystalline form
what are the three crystalline classifications
Alpha (α), beta prime (β’), and beta (β)
classify the classifications from least stable to most
alpha , beta prime, beta
classify them from highest melting point to lowest
beta, beta prime, alpha
whats plasticity
ability of a solid fat to hold its shape but still be moldable
what does plasticity determine
spreadability
what does plasticity increase with
temperature and degree of unsaturation
what are four other functions of fat
flavor, texture, appearance, sateity
how does fat influence flavor
help absorb fat soluble flavor compounds
how does fat influence texture
causes food to feel more moist
how does fat influence appearance
glossy sheen to foods
