To investigate the effects of different cooling rates on lipid changes in steam pot chicken cans after high-temperature sterilization, this study employed non-targeted lipidomics to analyze favorable cooling conditions following the sterilization process. Five treatment groups were set up: A (sampled without cooling after sterilization at 121 ℃, serving as control), B (cooled at –35 ℃ at a cooling rate of 2.40 ℃/min after sterilization), C (cooled at –15 ℃ at a cooling rate of 1.50 ℃/min after sterilization), D (cooled at 5 ℃ at a cooling rate of 1.01 ℃/min after sterilization), and E (cooled at normal temperature at a cooling rate of 0.26 ℃/min after sterilization). The results showed that the crude fat and crude protein contents of the four experimental groups decreased with decreasing cooling rate. A total of 1600 lipid molecules were identified in canned steam pot chicken, belonging to 73 subclasses in 5 classes, among which glycerol esters (GL) accounted for the largest proportion. Totally 26 differential lipid molecules were selected by multivariate statistical analysis, among which triglyceride (TG) and phosphatidylcholine (PC) were the main ones. The abundance of TG and PC showed significant differences with the decrease of cooling rate. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that glycerophospholipid catabolism was involved in the cooling process and served as an important pathway affecting lipid changes in steam pot chicken cans during cooling to room temperature after high-temperature sterilization. Significantly smaller lipid changes were observed in Group B than the other cooling groups (P < 0.05), while group E showed a slow decrease in internal temperature, making it prone to temperature-induced lipid changes. The results of this research provide a theoretical basis for the processing and storage of prepared meat dishes stored at room temperature.

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.