Effects of some refining process steps and oil extraction methods on total aflatoxin levels in pistachios and ochratoxin a levels in olives

In this study, the effects of different extraction methods on aflatoxin in pistachios and OTA in olives and the effects of refining process steps on aflatoxin in pistachio oil and OTA in olive oil were investigated. Two different sample groups were used for oil extraction from pistachio samples, both naturally contaminated samples and 15 µg/kg total aflatoxin inoculated samples. In the study, oil extraction was carried out using cold pressed, cold pressed from roasted samples, soxhlet extraction with n-hexane and soxhlet extraction with petroleum ether. It was determined that the oil extraction methods were effective on the transfer of aflatoxin to the oil in both sample groups and there were differences between the methods. In the study conducted with naturally contaminated pistachio samples, the lowest Total aflatoxin transfer to pistachio oil occurred in soxhlet extraction with n-hexane with a rate of 9.04%, followed by soxhlet extraction with petroleum ether with a rate of 11.30%. It was determined that the highest amount of aflatoxin transfer to the oil occurred in the cold pressed method from roasted samples with a rate of 17.18% and the cold pressed method with a rate of 18.39%. In the study using pistachio samples spiked with aflatoxin, the lowest aflatoxin transfer to the oil was achieved in the soxhlet extraction with n-hexane with a rate of 10.80% and the soxhlet extraction method with petroleum ether with a rate of 12.12%, followed by the cold pressed method from the roasted samples with a rate of 17.10%. The high aflatoxin transfer rate was 19.20% in the cold pressed method. Two different sample groups were used for oil extraction from olive samples, both naturally contaminated samples and 15 µg/kg OTA inoculated samples. Cold pressed, hot pressed, soxhlet extraction with n-hexane and soxhlet extraction with petroleum ether were used in the study. In both sample groups, it was determined that the oil extraction methods were effective on the transfer of OTA to the oil and there were differences between the methods. In the study conducted with naturally contaminated olive samples, the lowest OTA transfer to olive oil was obtained by soxhlet extraction with petroleum ether with a rate of 8.98% and with soxhlet extraction with n-hexane with a rate of 14.84%; The highest OTA transfer was detected in the hot press method with a rate of 30.33% and the cold press method with a rate of 34.46%, respectively. The lowest OTA transfer from OTA spiked olive samples to olive oil was achieved in soxhlet extraction with petroleum ether with a rate of 6.23%, followed by the soxhlet extraction method with n-hexane with a rate of 17.23%; It was determined that the highest OTA transfer was realized in the hot press method with a rate of 36.80% and the cold press method with a rate of 39.94%. In the refining study, degumming, neutralization and bleaching processes were used to determine the effects of refining process steps on aflatoxin in pistachio oil and OTA in olive oil. In the pistachio oil study, 15 µg/kg aflatoxin was spiked into aflatoxin-free pistachio oil and the effects of refining process steps on aflatoxin were investigated. The most effective step in reducing aflatoxins in pistachio oil was degumming with 69.50%, followed by neutralization with 58.19% and bleaching with 21.49%. At the end of the refining process, it was determined that the amount of aflatoxin in pistachio oil decreased by 90.33%. In the olive oil study, 15 µg/kg OTA was spiked into olive oil samples and the effects of refining process steps on OTA were investigated. As a result of the study, it was determined that the most effective method on OTA in olive oil was neutralization with a rate of 92.37%, followed by bleaching with a rate of 39.04% and degumming with a rate of 49.25%. At the end of the refining process, it was determined that the amount of OTA in olive oil decreased by 97.80%. As a result of the studies carried out with pistachios and olives, it has been determined that the amount of aflatoxin/OTA in the final product can be reduced to very low levels with the combined application of oil extraction and refining process steps in both aflatoxin and OTA amounts.