Chapter 8.2 (Nov 15)

Question 1

T/F

to an extent, you can determine dietary fat quality from the color and smell

Answer 1

true

dark colored oils usually have more impurities

Question 2

the higher the % of free fatty acids, the more ___

Answer 2

problems with the product

less ideal for consumption is lots of free fatty acids present

Question 3

free fatty acids indicate: ___________

they’re ____ and susceptible to ____

Answer 3

breakdown of TG

acidic
oxidation

Question 4

oxidation=

reduction=

Answer 4

• atoms loses an e-

- atom gains an e-

Question 5

rancidity=

Answer 5

• oxidation of an oil- when it goes bad

- oxidatively damaged fatty acids

Question 6

what are some things that affect rancidity?

Answer 6

• fat type- degree of saturation
• availability of oxygen
• moisture (more water= oxidation happens faster)
• enzymes
• metals- act as catalysts
• heat
• uv light

Question 7

protection from oxidants=

Answer 7

antioxidants

Question 8

why are bottles of oil packed with N2?

Answer 8

the N2 replaces the O2

- if it was left as O2, it would oxidize the fatty acids

Question 9

___ _ bonds are particularly susceptible to oxidative damage

Answer 9

double C

Question 10

what are 2 methods used to predict fat stability?

Answer 10

• oxidative stability index (OSI)

- active oxygen method (AOM)

Question 11

how does the oxidative stability index work?

Answer 11

• determines the relative resistance of fats/ oils to oxidation
• high temp + air movement
• rapid TG degradation –> volatile organic acids
• rapid rise in conductivity (induction point) = oxidative failure
  .

Question 12

Initial peroxide value (IPV):

Answer 12

oxidation by potassium iodine (iodide reacts with peroxides)

Question 13

what’s being measured in an IPV is not the damaged compounds themselves. explain this

Answer 13

Not measured: the damaged compounds themselves (eg oxidized fatty acids)

Measured: the liable compounds that appear as damage is being done, but then disappear (eg peroxides), leaving the damage behind

Question 14

in OSI, what does it mean if there’s a longer time to oxidative failure?

Answer 14

• more antioxidant protection
  OR
• less oxidation that has already taken place

Question 15

how does the active oxygen method (AOM) work?

Answer 15

= a measure of oxidation potential (how much could happen, but has not yet)

• measure IPV
• add heat, bubble air through sample for 20hrs
• determine peroxide value again

Question 16

consumption of oxidized oil can lead to the following 3 effects in animals

Answer 16

1. cell membrane damage
2. DNA damage
3. aging

Question 17

when are antioxidants added to fat?

Answer 17

• during manufacture

- to finished feed

Question 18

most feed antioxidants are based on a ___ group

Answer 18

phenol

Question 19

what does the phenol group do in feed antioxidants?

Answer 19

• remove the free radical (absorbs the unpaired e-) from the oxidatively damaged fatty acid –> forms a stable radical

Question 20

what’s the name of the antioxidant commonly used in animal feed?

Answer 20

ethoxyquin