RESUMEN
Deep frying is the most common method used for food preparation worldwide, which can lead to several chemical changes in used fat or oil in frying process including oxidation and polymerization. This study aimed to determine the effect of heating and different storage conditions on the disposal point of four types of the most common edible oils available in the Iranian market without and with the presence of food in terms of acid value (AV) and total polar compounds (TPC). AV and TPC of three types of marketed sunflower oil (especially for frying, cooking, solid vegetable) and ghee heated at 110, 150, 180, and 200°C with a portable oil meter DOM-24 (ATAGO, Japan) were determined. They were measured without the presence of food at four different temperatures and four different times in five storage conditions and with the presence of frying food (chicken and potatoes) at 110°C for 20 min in three replicates. The results showed that the AV and TPC contents in the case of ghee were above national and international standards without the presence of food. Also, in the process of frying chicken and potato, the reusability of all the studied oils was not possible for the second time and reached the disposal point. The increase in the rate of AV and TPC of oils was: ghee (Kermanshahi oil) > liquid cooking oil > frying oil ≥ solid vegetable oil.
RESUMEN
BACKGROUND: Soil and effluent of lead and zinc industries contain high concentration of cadmium. The present study was conducted to isolate tolerant fungal strains from cadmium -polluted sites in Zanjan province, Iran. METHODS: Cadmium tolerance and bioremediation capacity of seven isolates including Aspergilus versicolor, Aspergillus fumigatus, Paecilomyces sp.9, Paecilomyces sp.G, Terichoderma sp, Microsporum sp,Cladosporium sp were determined. RESULTS: Minimum inhibitory concentration values among 1,000-4,000 mg l-(1)proved great ability of isolated strains to survive in cadmium polluted environments. The most tolerant fungi, Aspergilus versicolor, showed tolerance index of 0.8 in 100 mg l-(1) cadmium agar media. Fungal resistance against cadmium is depended directly on strain's biological function. A. versicolor was found to bioaccumulate over7 mg of cadmium per 1 g of mycelium, followed by 5.878, 5.243, and 5.075, 4.557 by Paecilomyces sp, Aspergilus fumigatus, Microsporum sp and Terichoderma sp, respectively. CONCLUSION: It can be noted that tolerance of the strains appears to be independent from bioaccumulation capacity. Finally, the results indicated that A. versicolor could be a prospective candidate for bioremediation processes.