• Is a measure of secondary oxidation.
• Suitable to determine quality of crude oils and
efficiency of the processing procedures.
• Not suitable to detect fat oxidation.
• Principle: ρ-anisidine reacts with aldehyde
compounds in an oil, producing yellowish
reaction products
The method (56) measures light absorbance of
aldehydes at 350 nm, primarily 2-alkenals, and 2,4-dienals. But it is not entirely specific
because the color intensity developed depends not only on the concentration but also on the
actual structure of the aldehyde. Therefore, the result is comparable only within an oil type
because of the initial difference in the value among oil sources (5 9).