Optimization of Oxidative Stress Indicator Workflows for Enhanced Quality Control of Rendered Meals and Fats Utilizing the CDR FoodLab® Analyzer: Peroxide Value and Free Fatty Acids

At the 2022 AOCS meeting, Quartz Analytics, CDR FoodLab® exclusive distributor in USA, presented research conducted in collaboration with Tyson, sharing insights from their 2019 study. 

Following this, Quartz Analytics participated in the Pet Food Alliance, where they've been active since 2019. The growing recognition of the CDR FoodLab® at these events reflects its increasing impact across the industry.

In the United States, over 56 billion pounds of raw materials derived from animals are converted to approximately 9 and 10 billion pounds of rendered fats and protein meal, respectively. With this size and scope, it is a necessity for quality control teams to have access to methods that are reliable, accurate, intuitive, robust, and rapid to keep up with the ever-growing demands and ensure finished product quality.

Two primary indicators to evaluate oxidative stress of protein meals and fats are peroxide value (PV) and free fatty acid (FFA). Industry estimations suggest that the lack of standardized oxidative test methods costs the ingredient and food industries millions of dollars.

Recently, industry leaders have collaborated to tackle these challenges by evaluating and validating new platforms. One recognized platform is the CDR FoodLab® analyzer, a pre-calibrated, easy-to-use photometer that can perform multiple oxidative stress analyses, including Peroxide Value (PV) and Free Fatty Acids (FFA), in a variety of products. The rendering industry has recognized its potential, and industry leaders, in conjunction with CDR FoodLab®, validated the equipment against the AOCS official methods Cd 8b-90 and Ca 5a-40 for PV and FFA, respectively.

Seventy-five meat meal samples of various types were analyzed over three days, at 25 samples per day. Samples were run side-by-side using the AOCS Official Method Cd 8b-90 with ether extraction and the CDR FoodLab® flour calibration with n-propanol as the extraction fluid.

The CDR FoodLab® and its accompanying test kit for peroxide value utilizes the fact that R-OO-R peroxides oxidize Fe2+ ions. The Fe3+ ions resulting from oxidation are grouped and form a complex. Its colorimetric intensity, measured at 505nm, is directly proportional to the concentration of peroxides in the sample. Results are expressed as meqO2/Kg.

Results of the peroxide value of various meat meal samples tested on the CDR FoodLab® flour
curve and AOCS Official Method Cd 8b-90. Samples that did not have results or results exceeded 30
meqO2/Kg are not listed.

When comparing the results of the AOCS Official Method Cd 8b-90 to the CDR FoodLab®, there was a clear correlation between the results, indicating that the CDR FoodLab® may provide a solution for tackling oxidation challenges in the industry. Using the results from this study, a new calibration curve was created in correlation with the AOCS Official Method Cd 8b-90 for the peroxide value on meat meals for the CDR FoodLab®. This allows meat meals to be tested for peroxide value more easily and efficiently than the official method while maintaining accurate results.

As the CDR FoodLab® has proven to be a valuable tool, further studies are being conducted using the technology for analyzing FFAs in addition to PV.

The CDR FoodLab® and its accompanying test kit for peroxide value utilize the fact that R-O-O-R peroxides oxidize Fe2+ ions. The resulting Fe3+ ions form a complex, and its colorimetric intensity, measured at 505 nm, is directly proportional to the concentration of peroxides in the sample. Results are expressed as meqO₂/Kg.

1. Meeker, D. (2006). Essential Rendering: All About The Animal By-Products Industry. Arlington, VA. Kirby Lithographic Company, Inc.
2. Frankel, E. (2012). Methods to Determine Extent of Oxidation, p. 99-127. Edwin N. Frankel, Lipid Oxidation, 2nd ed., Woodhead Publishing.