Details of Research Outputs

A robust method for identification of reconstituted milk based on the content ratio of lactulose to furosine determined by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed and validated in the current study. The results showed that the optimal sample preparation conditions for hydrolysis were as follows: temperature 115 °C, time 4 h, and HCl concentration 11.9 mmol/L. The validated method was optimal for the limit of detection (LOD) (0.01 mg/L) and limit of quantification (LOQ) (0.04 mg/L), the recovery rate of furosine (93.4–108.9%), and precision (relative standard deviation at 1.38–3.85%). Due to the satisfactory separation of lactulose from lactose on the CNW Athena NH column and the high sensitivity detection of LC-MS/MS, the detection limit of lactulose was 0.05 mg/L, while the recovery was 89.9–105.6%. The optimized method was applied to the analysis of milk products collected in the Chinese market. The results showed that 98.2% of milk products were eligible for consumption when labeled as containing raw milk. Therefore, this technique is proposed as a robust analytical method to discriminate reconstituted milk products using the content ratio of lactulose to furosine as a marker.