Glycoalkaloid transformation during potato crisps production? Method validation and industrial trial

The aim of the industrial trial was to monitor the contents of the glycoalkaloids α-solanine, α-chaconine and their aglycon solanidine along the production process from unpeeled raw tubers to potato crisps. This should identify process factors that reveal possible process-related reduction or enrichment of these substances. The successful validation of an LC–MS/MS method using an external calibration for the determination of the glycoalkaloids α-solanine, α-chaconine and its aglycone solanidine met the requirements of the monitoring recommendation EU 2022/561, both, in terms of sensitivity and in view of the required enzyme inactivation. For the tested potato variety, none of the 15 industrially produced samples exceeded the proposed indicative value of 100 mg total glycoalkaloids/kg product mass (range: 13.2 mg/kg for peeled tuber to 67.6 mg/kg for potato crisps). Finally, solanidine contents were measured for the first time in-line a potato crisps production, ranging from 0.03 to 0.14 mg/kg product mass. The glycoalkaloid contents were additionally calculated as fat-free potato dry mass (ffpdm) to enable a standardized comparison of analytical values. With regard to this newly introduced reference value in this kind of process control, the ffpdm, a significant change of the glycoalkaloid contents during the production process of potato crisps after the peeling process could be excluded. This finding refutes current literature knowledge dealing with non-standardized results based on pure product weight ignoring water loss and/or fat intake along the production process. Starting from the unpeeled tuber to the final potato crisps, a glycoalkaloid reduction of 62% on average related to ffpdm could be achieved during the process, mainly related to the peeling. In contrary, the frying process contributed only insignificantly to the glycoalkaloid reduction.