Analysis of Palestinian Olive Oil of Different Storage Ages by Fluorescence Spectroscopy Technique

This work focuses on the effect of storage age of Palestinian olive oil on the emission and absorption wavelengths using the fluorescence spectroscopy technique. In addition, the effect of storage age of olive oil on the physical properties: viscosity, refractive index, acidity, and mass density are studied. The results of the emission and absorption spectra of olive oil samples at different storage ages give indication about how the amounts of the fluorescent components of olive oil affected by storage age. It was noticed that all vitamin E components, chlorophylls and phenolic compounds decrease as the storage age increases. The viscosity, refractive index, acidity (FFA%) and mass density for the sample collected from Saida (S2) of 5 years storage age at 25oC are found to be 58.9 cP, 1.4672, 2.98% and 0.90922 g/cm3, respectively. The viscosity, refractive index and mass density of olive oil samples at different storage ages decrease as the storage age increases, whereas the acidity increases as the storage age increases. The measured viscosity, refractive index, acidity and mass density of olive oil samples at 5 years storage ages agree with the standard values. The olive oil of storage age less than 5 years is considered as an edible olive oil. The Palestinian standard values of olive oil for viscosity, refractive index, acidity and mass density are regarded as; 84.0 cP – 63.6 cP, 1.4677 – 1.4705, 0.8 % - 3.3 % and 0.910 g/cm3 – 0.916 g/cm3, respectively (PS188, 1997).