The Metrohm oxidation stability of fats and oils is an important parameter for quality controls in the food industry. Ideally, the determination is made with the Rancimat method, which is suitable for both liquid and solid samples.
Its determination takes place directly in the sample or, in cases where this is not possible, in the extracted fat following cold extraction.
Solids with a high amount of fat, such as nuts and oil seeds (e.g., hazelnuts, almonds, sunflower seeds, sesame seeds, etc.), can be measured directly. Before the sample is weighed in, it has to be crushed to small grains, e.g., by a mortar. Care has to be taken that the sample is not overheated and not contaminated by traces of transition metals.
Additionally it is important that the grain size distribution of the crushed sample is approximately the same between measurements since it has an influence on the induction time.