PV was determined according to the Norme ISO 3960 (1977).
About 5 g of oil was mixed with 10 ml of chloroform then 15 ml of
acetic acid. 1ml of saturated potassium iodide (KI) was then added.
The mixture was kept 5min in darkness with continuously shaking,
and then 75 ml of distilled water were added. Sodium thiosulfate
solution (Na2S2O3) 0.01 mol/l was used for titration in the presence
of starch solution as indicator until brown coloration disappeared.
PV was calculated according to the following Eq.