Mohammed Salaheldeen, Safa Ali Mohammed Ali Elkhlil
The objectives of this study are to assess the quality of some commercial olive oils imported to Sudan. Six samples from different origins (Tunis, Turkey, Spain, Saudi Arabia, and Lebanon) were collected from the local markets. Physical properties (Refractive Index, Density, and Viscosity) and chemical properties (Free Fatty Acids, Peroxide value, Saponification value) of the samples were determined to assess their quality and discussed in the light of International Olive Oil Council (IOOC). Furthermore, The FT-IR spectra of all samples were determined to verify their structure. The quality of the oils during storage and heating were also examined. Physical analysis revealed that the refractive index and viscosity are consistent with the value set by the IOOC. As for the density, the samples J and M produced in Tunis and Lebanon, respectively, were slightly higher than the maximum limit of IOOC. The results of chemical properties showed that the acidity, as oleic acid%, falls in the range 0.11 to 1.07. According to IOOC, based on acidity, all the samples are extra virgin olive oils except sample M from Lebanon is virgin olive oil. The peroxide values PVs (meqO2/Kg) for all samples were found below the maximum limit (20) of IOOC. The saponification values SVs (mg KOH/g) for all samples were in good agreement of the range specified by IOOC (184-196) except sample S (Saudi Arabia) showed, significantly, higher value (233) than the maximum of IOOC. Based on changes in PVs, FFAs and UV absorption (E270) during heating and storage, sample J (originated from Tunis) is the most stable during heating, whereas, sample K (originated from Turkey) showed the highest stability during storage. The present studies indicate that all samples showed good quality for human consumption, during storage and heating, except the sample S (from Saudi Arabia) needs further investigation.
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