Thermal Oxidative Degradation of DHA Microcapsules: Insights from Physicochemical Properties and Non-Targeted Lipidomics

With rising demand for healthy diets, microencapsulated oil powders, especially docosahexaenoic acid (DHA) oil powder for infant formula, have gained attention. This study evaluated the stability of DHA powders from four brands by analyzing physicochemical properties, oxidation indicators, and flavor compounds, and explored the underlying mechanisms. Brand C showed better stability, with the lowest browning index (17.27), highest enthalpy (65.22 J/g), and a high peak temperature (97.00 °C). Its oxidation induction period exceeded 72 h. Its peroxide value decreased overall with fluctuations, whereas its anisidine value increased during heating. Free radical signals showed the smallest increases. Although malondialdehyde increased moderately, flavor changes were minor. Brand C was then analyzed by non-targeted lipidomics, identifying 148 differentially expressed metabolites. Heating was associated with changes in the relative abundances of lipid features. This study characterizes changes in commercial DHA microcapsule powders during heating and provides information relevant to ingredient stability assessment.