Superheated steam treatment modulates lipid-volatile metabolomics associations and improves storage stability of highland barley (Qingke).

This study examined the impact of superheated steam (SS) treatment (160 °C, 12 min) on lipid metabolism, volatile organic compounds (VOC), and related metabolic pathways in Qingke stored for six months. SS pretreatment reduced total free fatty acid (FFA) by 49% and malondialdehyde by 32% compared with untreated sample after storage. A total of 148 lipids (5 differential subclasses) and 339 VOCs (15 subclasses) were identified. SS was associated with reduced degradation of key phospholipids, including lysophosphatidylcholines (LPC) and lysophosphatidylethanolamines (LPE), while increasing relatively abundance and diversity of volatile compounds, including heterocyclics and terpenoids. Correlation analysis revealed that SS weakened FFA-VOC associations while strengthening LPC/ modulating LPE-VOC linkages. Metabolic enrichment suggested activation of α-linolenic and linoleic acid metabolism in untreated Qingke over storage, whereas SS-treated samples exhibited enhanced limonene/pinene degradation, monoterpenoid biosynthesis, and unsaturated fatty acid biosynthesis. Overall, SS pretreatment improved both flavor attributes and oxidative stability during Qingke storage.