The effect of food thermal processes on the residue concentration of systemic and non-systemic pesticides in apples

Abstract

The goal of the present study was to estimate the distribution and migration of eleven systemic and non-systemic pesticides between the skin and the pulp of apples. Additionally, the behaviour of acetamiprid, boscalid, bupirimate, cyprodinil, flonicamid, fluopyram, pirimicarb, pyrimethanil, thiacloprid, deltamethrin, and fludioxonil in two apple varieties during four thermal processes ranging between −40 °C and 150 °C was discussed. Gas and liquid chromatography-tandem mass spectrometry were used for analytical investigation. Depending on the apple variety, differences in the concentration of substances in the pulp and skin were observed. Pirimicarb had the highest average transfer to the pulp at 83%, while, boscalid and deltamethrin (97% and 98%, respectively) remained on the skin. Unexpectedly, boscalid was significantly more present in the apple skin than in the pulp. The process that most effectively reduced pesticides in apples with skin was drying (11 compounds were reduced by 59%); in apples without skin, it was the dry pasteurization process (8 compounds were reduced by 50%). Thermal processes resulted in processing factors (PFs) in the range of 0.06–0.98 in the case of ten pesticides. The only pesticide whose levels were not decreased due to technological processes was acetamiprid. Its residues were concentrated after four thermal processes (PF = 1.00–2.45). The lyophilization process reduced the pesticide residues to varying degrees. Bupirimate and fluopyram amounts in the apple without skin were reduced by 16–20%, while deltamethrin and flonicamid amounts by 100%. The relationship between pesticide distribution and behaviour was discussed. The highest positive value of the correlation coefficient between the physico-chemical properties of active substances and processing factors was recorded for water solubility (SW) and PF values in the case of the pasteurization process. This new data will contribute to gaining a better understanding of the relationship between selected pesticides and the efficacy of their removal.