Autoxidation Flashcards
To initiate an autoxidation reaction, hydrogen has to abstracted from a fatty acid from: A. The carboxylic end of the fatty acid B. The CH3 end of the fatty acid C. A double bound within the fatty acid
c
The abstraction of a hydrogen converts a fatty acid into: A. An aldehyde B. A Ketone C. A free radical D. An
C
When a free radical reacts with molecular oxygen it will produce: A. A epoxy radical B. A hydroperoxide C. An alkoxy group
A
An alkyl, carbon and hydrogen chain, group singular bonded to oxygen :
alkoxy radical
Milli-equivalents of peroxide oxygen per 1000 grams of fat is:
PV value
A fatty acid is more susceptible to autoxidation with an increased number of:
db
After abstraction of hydrogen, the double bond is saturated
False
Singlet Oxygen is a form of Oxygen that is: A. High in energy B. Far more reactive toward organic compounds C. Slightly different in its physical properties from the prevalent form or Oxygen D. Produced by photochemical reactions in the oil sample E. All of them F. None of them
E. all
T or F : Beta scission is a reaction that leads to the splitting of the C-C bond
True
The undesirable off-flavors and odors associated with oxidized fats and oils is called:
rancidity
T or F : Oils are bottled in dark glass containers to protect them from autoxidation
T
When the two electrons in a cleaved covalent bond are divided equally between the products, the reaction is called:
homolytic cleavage
Homolytic cleavage results in the formation of:
free radical
The peroxy radical is formed as a result of: A. Abstraction of hydrogen from a fatty acid B. Reaction fatty acid radical with oxygen C. Both of them D. None of them
B
T or F : The peroxy radicals are stable molecules
F
T or F : The formation of peroxides is infinite
F
Aldehydes resulting from the decomposition of the alkoxy radical can produce alcohols by:
reduction
At low concentrations of hydroperoxides the dominant reaction is the:
monomolecular
T or F : The PV increases linearly with time
false
Thiobarbituric Acid Test measures the concentration of
malonaldehyde
Increased number of double bonds increases autoxidation rate due to increased ……. structures in the FA.
resonance
…… is needed to produce singlet oxygen during a photochemical reaction
energy
T or F : Linolenic acid hydroperoxides will start to breakdown very early during autoxidation.
T
T or F : Chelating agents are true anti-oxidants.
False, synergistic agents
Which antioxidant is this?
Gossypol
What is this molecule? Why is it relevant to oxidation
2-(2-pentenyl)-furan. It is relevant because it is the common molecule found in all rancid oil and it is the reason for the reversion flavor of soybean oil
T or F : freezing an oil reduces the autoxidation rate
false
Why does transformers need to be monitered ?
becuse no oxygen and the H˚ from homolytic cleavage can recombine into H2 and buildup of gas can make the transgormer explode
What are the primary oxidation compounds?
hydroperoxide (ROOH) and peroxides (ROOR)
T or F : the monomolecular reactions give peroxy ROO˚ radicals
false, the monomoleculare rxn (ROOH –> RO˚ + OH˚) while the bimoleculare reaction (2ROOH –> ROO˚ + RO˚ + H2O)
What is measured when we measure the PV
the primary oxidation products (hydroperoxide : ROOH)
What is the formula of the PV?
2 KI + 2 R-O-O-H → I2 + 2 KOH + 2 R-O-H
What is special that can happen during the termination step of linoleic aicd?
Dimer fromation
