Fish oil is widely used as a source of omega-3 fatty acids, especially EPA and DHA, in dietary supplements, functional foods, and pharmaceutical formulations. However, because fish oil contains highly unsaturated fatty acids, it is naturally sensitive to oxidation. Oxidative deterioration can affect product quality, stability, flavor, and nutritional value. Therefore, oxidation control is one of the most important aspects of fish oil quality management.

For manufacturers and suppliers, monitoring key oxidation parameters helps ensure that fish oil maintains its purity, freshness, and effectiveness throughout processing, storage, and transportation.

Peroxide Value (PV): Measuring Primary Oxidation

Peroxide Value (PV) is one of the most commonly tested indicators for fish oil oxidation. It measures the level of primary oxidation products, mainly hydroperoxides, which are formed during the early stages of oil oxidation.

A low PV indicates that the fish oil has experienced limited oxidation and maintains better freshness. During production, manufacturers typically control factors such as exposure to oxygen, light, and heat to prevent excessive peroxide formation.

Anisidine Value (AV): Detecting Secondary Oxidation

While PV reflects early oxidation, Anisidine Value (AV) measures secondary oxidation products, especially aldehydes that develop as hydroperoxides break down over time.

Fish oil may show a low PV but still have oxidation problems if hydroperoxides have already decomposed into secondary compounds. Therefore, AV provides additional information about the overall oxidation status and helps evaluate long-term stability.

TOTOX Value: Overall Oxidation Assessment

The TOTOX value combines both primary and secondary oxidation indicators to provide a more complete evaluation of fish oil quality.

It is calculated using the formula: TOTOX = 2 × PV + AV. This parameter is widely used in the omega-3 industry because it reflects the total oxidation level of fish oil more accurately than PV or AV alone.

A controlled TOTOX value indicates that the fish oil has been properly processed, stored, and protected from oxidation.

Factors Affecting Fish Oil Oxidation Stability

Oxidation can be influenced by multiple factors during the entire supply chain. High temperatures, oxygen exposure, moisture, and light can accelerate oxidation reactions. Proper refining processes, antioxidant protection, nitrogen flushing, and suitable packaging solutions are commonly used to improve fish oil stability.

For B2B buyers, selecting a reliable fish oil supplier with strict quality control procedures is essential to ensure consistent product performance.

Choosing High-Quality Fish Oil Raw Materials

High-quality fish oil suppliers should provide comprehensive quality documentation, including oxidation test results such as PV, AV, and TOTOX values, along with information about EPA/DHA content, heavy metal testing, and microbiological analysis.

By controlling oxidation parameters throughout production and storage, manufacturers can deliver fish oil ingredients with better stability, longer shelf life, and reliable nutritional benefits for supplement and pharmaceutical applications.

Keynovo provides high-quality fish oil raw materials with strict quality control standards, supporting global customers in developing stable and effective omega-3 products.