Key takeaways
Read the two component values before you read TOTOX. The combined figure can look acceptable while one component is heading in the wrong direction.
Peroxide value
Peroxide value (PV) counts primary oxidation products. It rises first, so it is the earliest warning that the oil has been exposed to oxygen.
PV is also the least stable of the three figures, because primary peroxides break down into secondary products over time. A PV that looks low on an older sample can simply mean the peroxides have already decomposed.
Anisidine value
Anisidine value (AV) measures secondary oxidation products – the aldehydes that produce the rancid, fishy note a consumer notices.
AV rises later than PV and it does not come back down. This is why a batch with a low PV but a high AV should be treated as oxidised, not as acceptable.
TOTOX
TOTOX combines the two: 2 × PV + AV. The factor of two reflects that peroxides decompose into roughly two secondary products.
Use TOTOX as a screening figure across incoming lots, then check the components whenever a value moves. If PV is low and AV is high, the oil oxidised earlier and the TOTOX figure understates the problem.
Setting a limit you can hold
Choose the limit from your own finished-product stability data. A limit tighter than your filling process can support will cause rejections that have nothing to do with the supplier, and a limit looser than your shelf-life claim will fail at the consumer end.
State the limit, the test method and the units when you request a quotation, so both sides are measuring the same thing.
Related products and guides
The specifications below are commonly supplied with a declared low-TOTOX option for oxidation-sensitive formulations.