A set of 72 samples were formalized by mixing pure olive oil with vegetable
oils: Corn, Soya bean, Sunflower, cotton by percentages of 5, 10, 20, 30 and 40
percet respectively. Specific extinction at wavelengths 232nm, 266nm, 270nm
and 274nm were
measured for three replicates of each sample by using
Spectroscopy technique in ultra violet range, ΔK value (alterative of variation of
the specific extinction at the wavelength of maximum absorption near 270 nm)
and R value (EB270nm / EB232nm) were calculated.
The results showed the possibility of using ΔK value to detect the
adulteration of Olive oil up to 6.5 ±0.004%, 4.4 ±0.004 %, 0.8 ±0.006% and
0.08±0.005% for Soya bean, Corn, Sunflower and cotton oil, respectively. While
these values at 270 nm were 5±0.048%, 5.8 ±0.048%, 1.1±0.077% and
2.6±0.053% in the same arrangement. The absorption value at wavelength
232nm did not show any sign in detecting the adulteration. According to R
value, the minimum detected percentages of adulteration were 20 and 10 for
Corn and Soya been oil, Cotton and Sunflower oil subsequently .
We recommend to use ΔK to detect the adulteration of Olive oil mixed with
low percentages of vegetable oil.
