Lipidomics unveils changes in oxidised lipids in human breast milk by high‐pressure processing

Summary Human breast milk is a complex fluid rich in bioactive molecules crucial for infant growth and development. Global health organisations recommend exclusive breastfeeding to optimise infant health. In cases where maternal milk is unavailable, donor breast milk from human milk banks (HMBs) serves as an essential alternative. Currently, human breast milk preservation relies on Holder pasteurisation (HoP), which, while effective at pathogen inactivation, can compromise breast milk's nutritional and biological properties. High‐pressure processing (HPP) is an alternative pasteurisation method that utilises high pressure to kill pathogens without degrading nutrition. This study examined HPP's impact on donor breast milk lipids, sugars and antioxidants. Metabolomics reveals diverse bioactive compounds, including lipids, polyphenols and polyketides, elucidating breast milk's complexity. Some lipid subclasses respond to HPP; ceramides decreased under both treatments, while fatty aldehydes and esters increased under specific HPP conditions. Additionally, we quantified oxidised lipids, notably dietary oxysterols (DOxS), known for pro‐oxidant and pro‐inflammatory properties. These findings enhance understanding of HPP targeted approaches and breast milk's complexity, contributing to innovative milk preservation techniques that could advance specialised infant nutrition and assist donor milk banking systems. This study explores high‐pressure processing (HPP) as a breast milk preservation method, revealing its impact on lipids, sugars and antioxidants. HPP maintains nutritional integrity better than traditional pasteurisation, offering a promising alternative for human milk banks and specialised infant nutrition.