Development of a method for acrylamide determination in dried fruits and edible seeds available on the Italian market

Acrylamide is a process contaminant due to thermal processing and absent in raw food (1). It is carcinogenic and neurotoxic and its level in food arouses great concern (2), although it still does not exist a legal limit for its concentration in foodstuffs. However, European Union recently fixed a recommended level of 1000 μg kg-1 for potato chips. This work focuses on the development of extraction and analytical method for acrylamide determination in dried fruits and based edible seeds using a QuEChERS approach. Sixty-eight samples of packed dried fruits (dried prunes and raisins) and edible seeds (almonds, hazelnuts, peanuts, pine nuts, pistachios, and walnuts) were purchased on the Italian market. After grinding, an aliquot of each sample was suspended in water and acetonitrile and then added of the content of a QuEChERS pouch (MgSO4 4.0 g + NaCl 0.5 g) in order to achieve the separation of water from acetontrile and to induce the migration of acrylamide into the acetonitrile phase. The suspension was vigorously shacked and centrifuged. The upper organic phase was transferred and dried by a gentle nitrogen stream and redissolved in water before analysis. The acrylamide determination was carried out by liquid chromatography coupled with mass spectrometry using a RP-HPLC-ESI-MS-Triple Quadrupole (TQ) equipment. Linearity, sensitivity, matrix effect, accuracy, and precision of the method were studied, also using food matrix reference materials. Then, the method was applied to samples. Results showed that only dried prunes (from 14.7 to 124.3 μg/kg) and peanuts (from 10.0 to 42.9 μg/kg) were appreciably contaminated with acrylamide, as a result of the processing techniques. Prunes are not subjected to high temperature during drying (70-80 °C) but the exposure time is quite long (24-36 h), while peanuts undergo the roasting process (160-180 °C; 25-30 min). These conditions are both critical and they promote the formation of acrylamide. All the other samples showed values below the limit of detection or the limit of quantification. The relative standard deviations, accuracy and good LOD and LOQ show that QuEChERS associated to LC-MS-TQ could be considered a good approach for acrylamide determination in dried fruits and based edible seeds, and it is promising also for other food matrices.