Fats & Oils Flashcards
What is temperature at which a fat/oil begins to emit some traces of smoke?
smoke point
what is the major function of heat transfer
amount used determines cooking method
What is an irritating and volatile aldehyde formed when glycerol is heated (when oil starts to smoke)
acrolein
^ Free Fatty acids due to hydrolysis of TAG during frying & small particles of frying food in the oil will both _______
lower the smoke point
- moisture transfer
- fat transfer
- crust formation
- interior cooking
are all steps of
deep frying
What is the ability of fat to cover a larger surface area to minimize the contact between water & gluten during the mixing of batters & doughs
shortening power of lipid
what products are solid during mixing, melts during baking, creates layers and results in flaky product?
pastries, piecrust, biscuits
what determines shortening power or lipids?
^ saturation, ^shortening power
during shortening power….
^fat, v gluten formation, ^ tenderness aka
chewiness
the shortening power, shortens the
gluten strands
what are 3 emulsion parts?
dispersed, continuous, emulsifier
What are two types of emulsions?
oil-in-water (O/W) (water is continuous phase, oil is dispersed)
water-in-oil (W/O) (water is dispersed phase, oil is continuous)
what is a compound containing polar & non polar groups so that it is drawn to the interface between the 2 phases of an emulsion to coat the surface of the droplets?
emulsifier
emulsifiers must contain both
polar and non-polar parts
- v surface tension of one liquid more than another
- adsorbed on the surface of the droplets
- chemically stable
- no flavor or pleasing flavor and odor
- colorless or light colored
- edicble (non toxic)
are all criteria for
emulsifiers
what indicates the strength that bond adjacent TAG molecules together and the bod between fatty acids in food?
melting point
stronger the bond….
high melting point
shorter fatty acids will have lower melting point in comparison to
longer fatty acids
unsaturated fatty acid will have ______ melting point compared to saturated
lower
Cis will have ______ melting point in comparison to trans fatty acids
lower
alpha crystals (pure fat) has the lowest melting point then beta prime crystals has medium melting point and what has the highest melting point?
beta crystals
Of the fat crystals which is least stable?
alpha crystals
Of the fat crystals which is most stable?
beta crystals
Various FAs in a TAG do not have specific Tm, food lipid melts
over a range of temperature
What is the refining step in which oils are chilled carefully to precipitate and remove fractions with high melting points that would interfere with the appearance and flow properties of salad dressings or other products congaing the oils?
winterizing
What oils have high melting pints and FA crystalize in the refrigerator?
Unwinterized oils
what oils such as olive oil, are edible and will become clear when reach room temperature?
unwinterized oils
What is the addition of H to an unsaturated FA in the presence of a catalyst (Ni) to reduce unsaturation of the molecule and raise the melting point?
Hydrogenation
What is the by product of partial hydrogenation?
trans fat
What is the treatment of a TAG to split FAs from glycerol backbone then re-organize them to form different fat molecules with a smoother consistency (more resistant to forming coarse crystals)?
Interesterification
interesterification is the process to take out the
partially hydrogenated products
What process includes heating & cooking chocolate to specific temperature, making it more resistant to melting and resulting in a smooth, glossy, hard finish?
tempering
what promotes table fat crystals?
tempering
what is the undesirable, fuzzy, grayish appearance on chocolates surface due to recrystalization of fat or sugar, that results from improper cooling, fat incompatibility, high humidity, or temperature fluctuation during storage?
blooming
what is off flavor due to exposure to minor amount of o2?
falvor reversion
what is unwanted odors & flavors
rancidity
