Tracking changes in flavor characteristics of dried pork slice during air fryer processing based on E-nose, gas chromatography-ion mobility spectrometry, and lipidomics techniques

In this study, the changes in flavor characteristics of dried pork slice at various stages of air fryer processing were systematically traced and analyzed using E-nose, gas chromatography-ion mobility spectrometry (GC-IMS) and lipidomics. The results showed that the volatile organic compounds (VOCs) and lipid composition of dried pork slice changed significantly at different processing stages. The analysis showed that the E-nose was able to differentiate between the odor profiles of different processing stages of dried pork slice, with significant differences between the samples. The GC-IMS detected 74 VOCs during the processing of dried pork slice, of which 61 were characterized and 19 differential signature VOCs were screened based on the partial least squares discriminant analysis (PLS-DA) model. Aldehydes and pyrazines increased significantly as the processing stage progressed, especially in the finished product stage. A total of 780 lipids were detected by lipidomics, among which triglycerides and phosphatidylcholine accounted for 50.26% and 35.00%, respectively, as well as degraded significantly during processing, and 38 differential lipid compounds were screened by using the PLS-DA model. Correlation analysis revealed that ethyl 2-hydroxypropanoate-D, ethyl 2-hydroxypropanoate-M, and 1-butanol,3-methyl-,acetate-D showed negative correlation with 38 differential lipids, while positive and negative correlations were found between the remaining 16 major VOCs and the differential lipids, indicating that lipid degradation was closely related to the generation of flavor compounds. This study revealed the key data of lipid degradation and flavor generation, which provided a scientific basis for optimizing the air fryer processing and enhancing the flavor quality of dried pork slice.