Oxidation Destruction Begins During Ingredient Manufacturing

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Oxidation Destruction Begins During Ingredient
Manufacturing
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Understanding Oxidation

• Oxidation is an irreversible reaction of oxygen
  with fats and vitamins that leads to their
  destruction
• Fats reduction in energy
• Vitamins degradation
• Primary and secondary oxidation products can harm
  the animal and impact performance
• Reduction in feed intake
• Reduction in BW and feed efficiency

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Chemical Representation
Heat Light Metals
Free radical
Alkylperoxy
O2
RH
RH
Hydroperoxide
Free radical
Heat Metals Light
4 free radicals
.
2 free radicals were formed
Attack the starting material
Indicates unstable radical
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How do we stop oxidation?
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Antioxidants

• How does an antioxidant work?
• Antioxidants stabilize free radicals by donating
  a hydrogen
• R H-N R-H
• R H-O R-H
• AO distributes the absorbed chemical energy
  throughout its large structure
• Energy sink

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Antioxidants

• Several AO are commercially available
• Ethoxyquin
• Final feeds and rendered products (fats and
  meals)
• BHT (butylated hydroxytoluene)
• Final feeds and rendered products (fats and
  meals)
• BHA (butylated hydroxyanisole)
• As a blend in final feeds and rendered products
• TBHQ (tert-butylhydroquinone)
• As a blend in final feed and rendered products
• Blends (EQ, BHA, BHT, TBHQ, Acids)
• Ex. Endox, Oxistat, Oxicheck

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How Do We Measure Ingredient Quality And
Oxidative Stability?
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Standard Oxidation Test Methods

• Four methods commonly used
• Initial Peroxide Method (PV)
• Active Oxygen Method (AOM, 20 hr)
• Oxidative Stability Index (OSI)
• Rancimat

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Initial Peroxide Method (PV)

• Measures concentration of hydroperoxides at a
  single point in time
• Downside of this analysis
• Analysis does not tell if peroxide level is in
  the formation or termination phase of the
  oxidative reaction

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Understanding Oxidation
Equilibrium
Initiation
Termination
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Active Oxygen Method (AOM)

• Measures concentration of peroxides over time
• Accelerated stress test
• Air is bubbled through at 98 C
• Peroxide Values are measured at several time
  points
• Initial, 4, and 20 h IPV
• Fats with less than 20 meq/kg peroxides at 20 h
  are considered stable

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Active Oxygen Method
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Modified Active Oxygen Method

• Measures the number of hours it takes to reach 20
  meq peroxides/kg fat
• The greater the number of hours it takes to get
  to 20 meq/kg fat the better the oxidative
  stability of the fat or the antioxidant

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Oxidative Stability Index (OSI)

• Measures the induction time or time it takes
  until the production of stable tertiary oxidation
  by-products
• Volatile fatty acids
• Accelerated stress test
• Fat is saturated with air at elevated
  temperatures (110 C, air flow rate 2.5 ml/sec)
• Automated analysis
• Downside of this analysis
• No industry standards exist to define a stable fat

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Oxidative Stability Index
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Oxidative Stability Index
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Rancimat

• Accelerated stress test
• Fat is saturated with air at elevated
  temperatures (110 C, air flow rate 5.6 ml/sec)
• Measures stable tertiary oxidative by-products
• Downside of this analysis
• No industry standards exist

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Need To Understand. Stability Test

• NOT all TESTs are created equal
• Sensitivity
• Reproducibility
• Effects of time
• Initial conditions of the fat
• This goes for ANTIOXIDANTS as well!

No Best Method To Measure Oxidative Damage In
Feed Ingredients
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Objective

• To determine if the effectiveness of five
  different antioxidants currently available on the
  Australian and New Zealand market are equal in
  their ability to stabilize two fat sources using
  four stability measurements (PV, AOM, OSI,
  Rancimat).

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Materials and Methods

• Five antioxidants were chosen for comparison
• Santoquin, BHT, Endox, Oxistat and Oxicheck
• Each antioxidant was tested according to the
  manufacturers recommended usage rate for poultry
  fat and tallow
• Four stability measurements were run on each
  antioxidant
• Peroxide Value Method (PV), Oxidative Stability
  Index (OSI), Rancimat and the Active Oxygen
  Method (AOM)

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Materials and Methods

• PV, AOM, Rancimat analysis were run at the
  analytical laboratories of Novus International,
  Inc.
• OSI conducted at an outside contract lab.
• Duplicate analysis were run only on the Rancimat
  data with statistical analysis done using the GLM
  procedure of SAS.

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Results
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Initial Peroxide Method (PV)
Poultry Fat Tallow PV (meq/kg)
4.15 2.54
Generally IPVs below 5 meq/kg are desired
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20 h Active Oxygen Method (AOM)
Antioxidant Poultry Fat Tallow
(meq peroxides/kg
fat) A 32.3 3.6 B
15.3 2.8 C 208.8 19.3 D
189.6 6.1 E
2.3 1.5 Control 254.7 52.7
PV below 20 meq/kg at 20 hr is desired.
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Modified Active Oxygen Method
Antioxidant Poultry Fat Tallow
(h to 20 meq peroxides/kg
fat) A 16 53 B 22
108 C 8 20 D
9 33 E 165
210 Control 8 14
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Rancimat Induction Time
Antioxidant Poultry Fat Tallow

(hours) A 6.5b 9.5c B
5.8bc 10.9b C 4.8cd
7.3e D 5.0bcd
7.9d E 20.8a
34.7a Control 4.1d 3.3f
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Oil Stability Index Induction Time
Antioxidant Poultry Fat Tallow

(hours) A 6.5 14.9 B
7.4 17.8 C 4.9 6.6 D
5.4 13.4 E
28.7 34.1 Control
4.7 6.0
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OSI vs Rancimat time it takes until the
production of tertiary oxidative by-products
Antioxidant Poultry Fat Tallow
OSI Rancimat OSI
Rancimat A 6.5 6.5b 14.9
9.5c B 7.4 5.8bc 17.8
10.9b C 4.9 4.8cd 6.6
7.3e D 5.4 5.0bcd 13.4
7.9d E 28.7 20.8a 34.1
34.7a Control 4.7 4.1d 6.0
3.3f
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Summary

• Poultry fat and tallow had low IPVs indicating
  good initial fat quality
• All methodologies used to determine the relative
  effectiveness of the five antioxidants resulted
  in similar ranking of products for both poultry
  fat and tallow.
• Rankings were similar despite the different end
  products being tested.

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Summary

• Product E performed the best regardless of the
  methodology used.
• The control, with no added antioxidant, performed
  the worst, regardless of methodology used!

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Conclusion

• The methodologies used to determine the
  effectiveness of the commercially available
  antioxidants demonstrate that these products
  differ in their ability to stabilize different
  fat sources.

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AntioxidantsTHE BEST WAY TO PREVENT OXIDATION

• Add antioxidants as early as possible!
• Antioxidants are oxidized before the fats
• The oxidized antioxidants are stable

Antioxidants DO stop the Oxidation
Process! Antioxidants DO NOT Eliminate Oxidation
By- Products!