Qualitative Investigation of the Consumed and Residual Oils in Food Products Prepared in Delicatessens and Confectioneries of the Town Of Shahinshahr and Meymeh in 2013

Heating vegetable oils at presence of air results in oxidative changes and production of hydro peroxides and volatile compounds. The main objectives of this study were to determine peroxide value and rancidity index of oil samples collected from delicatessens and confectioneries in the town of Shahinshahr and Meymeh, and to compare these parameters with the recommended standard values.
In this study was taken 103 samples from delicatessens and confectioneries. The Iranian standard procedures numbers 493 and 4179 were considered for sampling method and peroxide test, respectively. The rancidity index was examined in the Krays method. Analysis of the parameters to assess the accuracy of the results was carried out simultaneously at three different laboratories including school of health, Ibn Sina private laboratory and food and drug department.
Findings: The results showed 100% raw oil and 88.3 % consumed & extracted oil samples were permissible with regard to the peroxide standard. Also with regard to rancidity, 100 % of raw oil samples were valid, while 100 % of consumed oil and 85 % of extracted oil samples were decay. As well as 16.8 and 75.0 % of taken samples from units with health and Sanitation standards had Peroxide higher than permissible value, respectively. The results of the School of Public Health and IbnSina were also perfect matching.
This study showed that the peroxide test alone is not sufficient to determine oil quality and should use from other tests such as rancidity. Also health status of manufacturing units plays important role in improving these indicators.