The effects of under-tree fruits and physically damaged fruits on aflatoxin and ochratoxin formation in pistachio nuts

In this study, the presence of aflatoxins and ochratoxin A mycotoxins, which are an important risk in pistachio fruits, were investigated. In the study, pistachio fruits of Uzun and Siirt cultivars were used. The harvest of pistachio fruits was carried out at two different times as early harvest (boz harvest) and normal harvest (ben harvest). This study was carried out to determine the idea that pistachio fruits damaged by factors such as diseases, pests, physical deformation, and fruits that fall to the ground spontaneously before harvesting, which are called under-tree, may be more exposed to soil-borne molds and mycotoxin formation may be more in these fruits. Harvested pistachio fruits were sorted and stored after drying. In the study, the presence of aflatoxin was not detected in the under-tree nuts, which were risky. During storage, firstly AFB1 was found to be 0.2348 ppb (9th month) in Siirt ben harvest damaged nuts. The highest aflatoxin value (AFB1) was detected in Siirt ben harvest damaged fruits as 0.4429 ppb at 36th month. In terms of mycotoxins, none of the samples exceeded the upper limits specified in the TGK (Turkish Food Legislation). Ochratoxin A was not detected in any of the samples. Moisture content, water activity and total mold content of fruits were monitored as factors affecting mycotoxin growth after harvest and during storage. During the storage period, the water activity values were below 0.60 aw at all nut samples. The total number of molds was higher in damaged fruit samples; however, mycotoxin formation was not intense because the water activity was low. Free fatty acids and peroxide values, which are important factors for food quality, were examined in pistachio fruit oil. It was determined that these values started to exceed the limits of the legislation after the 24th month storage. Free fatty acids and peroxide values were higher in boz harvest fruit samples. The highest free fatty acid value was found to be 9.109% oleic acid at the 24th month in Siirt ben harvest damaged fruits during storage. The highest peroxide value was found as 23.00 meq O2/kg oil in Siirt boz harvest damaged fruits at 33rd month.