RENDOX® - Preserving Fat Quality

RENDOX® - Preserving Fat Quality

Oxidation effects on fat quality can be a major factor in the reduction of livestock and poultry feed quality. The oxidation effects on fat quality is an irreversible, naturally occurring process where fatty acids are attacked by free radicals and oxygen is absorbed. Initiated when fat is exposed to oxygen, metal ions, heat, enzymes and light, this process results in a conversion of fatty acids into harmful byproducts including peroxides and aldehydes. Oxidation dramatically affects the quality of fats and oils, which has been shown to have direct impact on animal health and performance, ultimately negatively affecting your business' financial bottom line. 

To protect your fat from negative oxidation effects on fat quality, an antioxidant system should be used. An antioxidant system should contain a combination of the following:

  • Synergistic blend of antioxidants to absorb free radicals before they destroy fatty acids
  • Metal chelators to bind metal ions, which may promote free radical oxidation
  • Oil-based carriers to better mix with fat molecules

The Kemin antioxidant systems approach provides the best blend of antioxidants specifically formulated for the protection of your feeds and fats.

Kemin Antioxidant Systems
    Ethoxyquin (EQ)
Product Animal Fats Vegetable Oils Blends Low EQ No EQ
RENDOX® ​AT 20 X       X
RENDOX​® CQ   X     X
RENDOX​® RG     X X  
RENDOX​® AC X       X
RENDOX® EQ X        

What's Happening in Your Fat Tank? Benefits of Antioxidants on Fat Quality

Fat quality solutions start with the purchasing of quality fat. However, high quality fat can easily be negatively impacted due to handling and storage conditions. Time of storage, application of heat and the mixing of different lipid sources all have direct implications on the production of peroxidation compounds.

Management practices implemented often focus on the amount of time fat is exposed and susceptible to oxidation. Unfortunately, this practice does not consider the layer of fat residue, which coats the inside of the tank, or the sludge buildup at the bottom of the tank. These residues contain high amounts of free radicals, which, once mixed with new fat, disperse and immediately promote oxidation of the new fat.

Treating fat with a Kemin antioxidant system will prolong the fat quality, ensuring you receive the maximum value from your fat. 

Case Study: Stabilizing Fat Tank Quality 


Previous fat quality testing indicated the customer feed mill in this study was receiving high quality, non-antioxidant treated poultry fat. The customer's fat tank was not being cleaned, causing concern that the quality of the fat leaving the tank was not the same as the quality of the incoming fat.1

Kemin Customer Laboratory Services (CLS) field study was conducted to determine:

  1. Quality of fat coming out of the tank
  2. Correct antioxidant system treatment level, if needed

Project Scope

The fat tank at the customer site was sampled three times per week (Monday, Wednesday and Friday) for three sampling periods.

  • Sample Period 1: Prior to implementation of the antioxidant treatment
  • Sample Period 2: 2 weeks post implementation
  • Sample Period 3: 4 weeks post implementation

Analysis Tests Conducted

Oxidative Stability
Index (OSI)
A test illustrating the potential for oxidation in a liquid fat. Results are reported in hours to induction (onset of oxidation), a higher value is more desirable.
Peroxide Values
Peroxides are the initial compounds produced by oxidation and are early indicators of active oxidation.
Testing for aldehydes, such as hexanal and 2,4-decadienal. These compounds are produced later in the oxidative process, following peroxides. 

Oxidation Analytical Testing Results

Change in oxidative status of poultry fat before/after implementation of an antioxidant system

Figure 1. Change in oxidative status of poultry fat before/after implementation of an antioxidant system (n = 3 for each designated time period)2

As the results of the field demonstration indicate, once high quality poultry fat was added to the untreated fat tank, blending of the fats allowed for the poor quality, free radical-loaded fat to immediately impact oxidation. The first series of samples confirm low OSI times and high levels of secondary oxidatives. After implementation of the antioxidant treatment system, OSI begins to increase, indicating improved stabilization of the fat. In addition, secondary oxidative levels begin to decrease, signifying interruption of the oxidative process. 

Stabilizing the quality of the previously untreated fat tank takes time. Even as new fat is added, OSI times and secondary oxidative levels continue to improve. 

1Kemin Internal Documents, 16-00129, 17-00011.
2Kemin Internal Document, 16-00090.

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