Which is recognition of symptom of Oil & Fat oxidation

Solution

Recognising an oxidation problem: Recognition of symptoms that allow the diagnosis of an oxidation problem is also important. Evidence that oxidation has occurred is generally quite apparent. Obvious signs are: 1. Rancidity. Oxidation of fats and oils results in off-odours and off-flavours. 2. Colour changes. Oxidation can result in either lightening or darkening in colour, depending upon the substrate. For example, fats and oils tend to darken. Pigments, especially carotenoids, tend to lighten. 3. Loss of odour . Essential oils such as citrus oils lose their distinctive fruity high notes of odour. 4. Viscosity changes . Fats and oils tend to thicken due to polymerization that is catalysed by free radicals.