Week6 Flashcards
T or F : when the FA undergo hydrogenation, the configuration necessarily change from cis to trans
no, not automatically
What are the functional properties of fats and oils in food? (7)
- Heat transfer agent
- tenderize baked products
- Lubricating agents
- Aeration
- Enhance flavors
- Contribute to texture and mouthfeel
- Feeling of satiety
What causes the flakiness in baked product containing a lot of FATS?
The chewiness is caused by protein strands in flour and FATS cut the protein strands.
What determine the flakiness?
Fat to flour ratio
How does lipids create aeration in food products?
They both are hydrophobic so fat can retain water bubbles in a batter.
T or F : fats and oils don’t have flavors on their own but they enhance flavors by dispersing flavor compounds
T
What is the major factor that has an impact on the functionality of fat
the degree of plasticity. (determined by the SFC that depends on the lipid profile)
Below the melting point, the lipid is ____
solid fat
What is the solid fat content ?
SFC is the state of solid fat and liquid oil that happens to lipid in a certain temperature range around the melting point.
Complete : olestra is a ____
sugar polyester
What are the two types of deteriorative reactions that can happen to fats and oils?
- Enzymatic rancidity
2. Oxidative rancidity
What is autoxidation?
The normal saturation of the double bonds of fat and lipids that happens over time with O2
What are the factors that influence the autoxidation?
1-High RH
2-light
3-metallic ions
4-heat
Complete : The rate of autoxidation is very slow for____ but
increases exponentially with increasing number of ____
Saturated fats
Double bonds
What can you do to a fat/oil mixture to reduce the autoxidation
- Antioxidants like vitamin E
2. hydrogenate the fat (decrease double bonds number)
What is rancidity?
The loss of quality of oil that occur with time (deterioative reaction) and results in unpleasant odors and tastes
What is lipolysis?
A kind of deteriorative reaction that occurat high temperature and in the presence of water that gives free FA and glycerol by the enzymes found in plants and oils
T or F : lipolysis and autoxidation in oils are bad for the health
False, lipolysis is not bad for the health but if the free FA content is higher than 1% the oil is non-consumable
T or F : lipolysis and autoxidation occurs when frying food
True in the case of autoxidation because of high temperature and presence of oxygene and in the case of lipolysis because of high temperature and the presence of water
What is the smoke point?
The temperature at wich fatty acid break appart and produce smoke. You also need to change the frying oil if the temperature went at the smoke point
What is the flash point?
The temperature at wich the lipids flame
What can you determine about a solution when you know its smoking point?
The degree of enzymatic or lipolysis that has occured in the sample
T or F : when choosing a frying oil, it is better that you choose a oil that is rich in free FA
False, because it will reduce the smoke point of an oil and you will need to discard it at much lower temperatures
What part of the pospholipid molecule can change and will dictate the type of phospholipid
The nitrogen based attached to the phosphate group at the C3 of glycerol
T or F : A phospholipid is a glycerol base with 2 fatty acids and a
phosphorus-containing acid attached
T
T or F : the flash point can be used to determine the degree of lipolysis that has occurred in a fat/oil sample
F, is is the smoke point (the T at which the FFA produce smoke)
Lower is the smoke point and ____ is the free fatty acid content of a sample
higher
