Fatty acid composition drives integrated changes in oxidative stability, phytonutrients and processing contaminants of diacylglycerols under thermal stress.

Diacylglycerols (DAGs) are edible lipids, but their use in thermal processing was underexplored. This study systematically evaluated how fatty acid composition influences the performance of cooking DAGs under heating. DAGs based on flaxseed (FDAG), corn (CDAG), and peanut (PDAG) were analyzed for thermo-oxidative stability, phytonutrient retention, and contaminant formation. FDAG exhibited the poorest oxidative stability, the most significant degradation of tocopherols and phytosterols, and the highest accumulation of 3-monochloropropane-1,2-diol esters (3-MCPDE). It was also found that chloride ions show less significance than DAGs on 3-MCPDE formation. Glycidyl esters level increased with temperature but degraded more rapidly above 240°C, especially in oils with higher unsaturation such as FDAG. In contrast, PDAG demonstrated superior thermal stability and lower contaminant formation. Therefore, compared to FDAG and CDAG, PDAG is more suitable for high-temperature cooking. These findings emphasize the need to tailor thermal processing conditions based on the specific fatty acid compositions of DAGs to ensure safety and quality.