Effect and Mechanism of Different Cooling Rates on Lipid Molecules in Steam Pot Chicken after High-Temperature Sterilization

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.