Studies of chemical methods for assessing oxidative quality and storage stability of feeding oils

Peroxide value (PV), thiobarbituric acid number (TBA), anisidine value (AV), percent free fatty acids (FFA), and carbonyl value (CV) methods were compared in different experiments for their sensitivity and practicality in assessing the oxidative quality of four feeding oils: salmon oil, soybean oil, canola oil (oil from low erucic acid, low glucosinolate rapeseed), and canola soap stocks. In the first experiment, among the four methods (PV, AV, TBA and FFA) studied, PV appeared to be the most practical for its sensitivity, simplicity, and economy when the four oils were oxidized by bubbling air through at room temperature for 792 hr. In the second experiment, using herring oil, all four methods tested (PV, AV, TBA and FFA) were sufficiently sensitive once the oxidation of herring oil had passed the induction period and the oil was highly oxidized. In the third experiment, of the four methods (PV, AV, TBA and CV) compared, AV was the most sensitive for measuring the oxidative quality of canola oil aerated at 100 C for 240 hr. Results of further studies suggested that herring and canola oils stored under commercial conditions were stable for at least one year.