the best method and technique to measure antioxidant activity in oils:

use of HPLC techniqu.

HPLC: High Performance Liquid Chromatography

The HPLC is just used to identify and quantify the component of various compounds , but for antioxidant activity.

Is it possible to extract the only known compounds before since some fatty acids, with double bond, in the extract might interfere the antioxidant assay ?

Thanks Supachai , your answer seems feasible. Now how can I extract the water-soluble antioxidant compounds from oi.?

You can just mix the oil (diluted) with TBARS, heat for 1 h, extract with butanol:pyridine (15:1) and measure against tetraethoxypropane. This will measure total levels of lipid peroxide (LPO). Waterr-soluble antioxidant compounds from oi? Initially, dissolve oil in methanol, then mix it with water. Water-soluble compounds from

oil might partition into water layer. If methanol/water layer is not separated, mix both of them with octane, shake, water-insoluble part would go to octane, the other part, i.e. the water soluble part might contain the water-soluble antioxidant compounds from oi.

DPPH can be dissolved in organic media (especially in alcoholic media), so it can be used for AO activity in oils. Further, ABTS can be solubilized in both aqueous and in organic media and is not affected by ionic strength, so the antioxidant capacity can be measured due to the hydrophilic and lipophilic nature of the compounds. If oil is your sample, ABTS can be employed to measure the activity of oil.

I agreed with Gudipati. that is the method we used in our just concluded work on rice bran extract, not yet publihed.

All of your answers are considered and much appreciated.

I would refer you to Prof Fereidoon Shahidi's contributions on this topic. Depending on if you are trying to measure the degree of oxidation, the oxidation resistance of an oil, the content of known antioxidants within an oil product or the functional antioxidant capacity under a given set of environmental conditions you would be looking to conduct very distinct analysis. Prof Fereidoon Shahidi's contributions would be the best place to start on this topic.

The crocin bleaching is the only one!!!!

Hi Scott: Your suggestion about Prof Fereidoon Shahidi's contributions paper is thankful.Let me try it.

Dear colleague,

i will send you the appropriate method as soon as possible