The qualitative characteristics of the oils prepared in the extraction oil stores in the presence of the customer

In this research, the chemical characteristics of sesame, rapeseed and sunflower oils prepared in the presence of the customer were compared with similar industrial-refined samples during two months of storage. Their levels of iron, copper, arsenic, and lead were also measured. The average of moisture and sedimentation contents of refined oil samples and sesame and rapeseed oil samples prepared in the presence of the customer were in the range of Iranian standard, but the average values for sunflower oil samples prepared in the presence of the customer was higher than the Iranian standard limit. The mean of the refractive index, iodine, and saponification values of all samples was in the range of standard. The oxidative stability index of prepared oils in the presence of the customer was less than the standard. The mean acidity and peroxide value of all oil samples were in the standard range but increased significantly during storage so that all samples were unusable on the last day of storage. The anisidine value of all samples increased during storage so that the average of this index in oil samples prepared in the presence of the customer was not in the standard range from the 40th day of storage. The Totox index of all oil samples also increased during storage, which was higher in sunflower oil. The results also showed that the cox index of sunflower oil was higher than the others. The average of the studied metals in all oil samples was in the standard range. The findings of this study showed that industrial refined oils have better chemical properties and stability and it is suggested not to use oils prepared in the presence of the customer for frying and it is recommended that keep them for a short time to cooking purpose.