Determination of Peroxide Value in Oil: Insights and Methods

The Peroxide Value (PV) measures the concentration of peroxides and hydroperoxides formed during the initial stages of fat and oil oxidation. A high PV indicates deterioration and potential health risks. Regular monitoring is essential for quality control and ensuring consumer safety. The PV at which oxidation becomes noticeable as off-flavor varies among oils. 

PV is a measure of primary oxidation in oils and fats. Fatty acids break down during oxidation, forming peroxides that adversely affect taste, aroma, and nutritional value. PV measurement is a useful tool for monitoring oxidation, but it's typically combined with other methods for a fuller picture of the oxidation progress.

Traditionally, PV has been determined by titration methods. However, advancements in technology have led to more sophisticated techniques like, Near infrared analysis and photometric analysis. Furthermore, the AOCS has developed an isooctane-based method as an alternative to the traditional chloroform-acetic acid mixture, addressing safety concerns.

The titration method involves reacting the peroxides in the oil with a solution, typically iodometric, and measuring the amount of iodine consumed. 

Titration is a commonly used method to determine the peroxide value in oils and fats, but it does have some drawbacks:

• Time-consuming: Titration can be a time-consuming process, as it involves several steps, including sample preparation, addition of reagents, and titration itself. This can make it less suitable for high-throughput analysis.
• Requires skilled personnel: Performing titration accurately requires skilled laboratory personnel who are trained in the technique. Inexperienced operators may introduce errors in the analysis.
• Chemical waste: Titration generates chemical waste, including the use of hazardous reagents like potassium iodide and sulfuric acid. Proper disposal of these chemicals is necessary to minimize environmental impact.
• Interference from impurities: Impurities or contaminants in the oil or fat sample can interfere with the titration process, leading to inaccurate results.
• Subjective endpoint determination: The endpoint in a titration is typically determined by an operator's judgment based on a visual indicator (e.g., starch-iodine). This subjective element can introduce variability in results.

The determination of Peroxide Value using near-infrared (NIR) spectroscopy offers several benefits over traditional methods.  It is a rapid technique, with results typically obtained within a few minutes. 

However, there are also some drawbacks using NIR spectroscopy for PV determination: 

• the accuracy of the results can be affected by the presence of interfering substances, such as water or other solvents
• the calibration models used for NIR spectroscopy can be complex and may require specialized expertise to develop and maintain.

The CDR FoodLab® method uses a photometric analysis technique. Faster and simpler than traditional methods, it requires smaller sample sizes and the operator don't have to handle toxic reagents. Any calibration procedures are required since the device is supplied pre-calibrated.

This method is especially suitable for all vegetable oils and animal fats.

You can analyze any kind of crude or refined oils as is without any problem of colour or viscosity. In case of solid fats, it is enough to melt it to collect it and carry out the analysis. 

You can analyze fats like Frying oils and fried snacks, oils in Bakery products, snacks and creams, Nuts, Butter and margarine, Natural oils, Oils for energy use (biofuels or biodiesel), Precious oils and essential or cosmetic oils, oils in Animal feeds and animal meals, oils in Pet Food, Avocado oil, Palm oil, Olive oil and so on.

For solid sample as bakery products, pet food, animal feeds and so on you can easily and quickly extract the oil from the solid sample using CDR Extraction System. After a short centrifugation we take the sample and we can carry out all the analysis.

As demonstrated by some comparative studies, the results of the peroxide value test obtained with the CDR FoodLab® method are well correlated with the reference method AOCS Official Method Cd 8-53. 

Furthermore, it is well correlated with Campden BRI Method TES-AC-360 based on ISO 3960 or AOCS Cd 8b-90 or AOAC 965.33.

Determining the Peroxide Value is crucial for maintaining the quality and safety of oils and fats. The CDR FoodLab® method offers an advanced, accurate, and user-friendly alternative to traditional methods, representing a significant advancement in food quality testing.