Fate of Chlorpropham during High-Temperature Processing of Potatoes

• Published in: Journal of agricultural and food chemistry Vol. 68; no. 8; pp. 2578 - 2587
• Main Authors: Göckener, Bernd, Kotthoff, Matthias, Kling, Hans-Willi, Bücking, Mark
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 26.02.2020
• Subjects: Chlorpropham - chemistry; Cooking; Herbicides - chemistry; Hot Temperature; Pesticide Residues - chemistry; Plant Tubers - chemistry; Solanum tuberosum - chemistry; radioactive tracing; potatoes; 14C-food processing; chlorpropham; fate of pesticides
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.9b06386

Chlorpropham is a widely used sprouting inhibitor applied on potatoes during their storage. Currently, severe concerns are raised regarding the potential formation of 3-chloroaniline from chlorpropham during heat treatment. The reactions degrading the molecule in the matrix are quite complex under harsh processing conditions, and a molecular investigation is thus challenging. This study aims to decipher the reaction pathways and to discover new metabolites in typical high-temperature food-processing steps. For this purpose, potatoes were treated with 14C-radiolabeled chlorpropham, stored for up to 6 months, and subjected to the traditional preparation steps of boiling, frying, and baking. A quantification method including an acidic hydrolysis was developed for analysis of free and bound analytes. All conducted processing steps led to a substantial mitigation of chlorpropham residues in the consumable products. Of the residues, 17 ± 6% remained in boiled tubers, while 27 ± 3 and 22 ± 3% remained in the fried and baked products, respectively. Chlorpropham was transferred into the surrounding media (boiling water, frying oil, and air, respectively). 3-Chloroaniline was only (raw tubers) or predominantly (processed tubers) present as a bound analyte and was shown to form during storage but not during processing. Additionally, nonextractable and nonquantified residues were detected in the baked and in the long-term-stored tubers after processing. Future studies will have to balance beneficial (mitigating) and potentially hazardous aspects of these results. By transferring the 14C-food-processing approach to a variety of substances, ingredients, and processes, it will be possible to further understand chemical reactions in food processing, finally leading to safer food.