Metabolomics reveals the mechanism of plasma-activated lactic acid pretreatment in maintaining the quality of tilapia (Oreochromis niloticus) after electron beam irradiation.

Tilapia is vital for food security but suffers rapid quality deterioration during storage. This study integrated physiological monitoring with LC-MS/MS metabolomics to investigate plasma-activated lactic acid (PALA) pretreatment combined with electron beam irradiation (EBI) on fillet quality and metabolism. The results showed that, compared with EBI treatment alone, the combined PALA-EBI treatment significantly reduced the initial total viable bacterial count, slowed the increase in volatile basic nitrogen and thiobarbituric acid reactive substances, and mitigated the reddening of fillet color. Metabolomic analysis revealed that EBI induced significant oxidative stress, disrupting metabolic pathways such as glycerophospholipids, fatty acids, nucleotides, and amino acids. PALA-EBI alleviated these metabolic disturbances by partially restoring long-chain acylcarnitine levels. Moreover, purine metabolism and glycerophospholipid metabolism were identified as key pathways associated with quality changes in tilapia fillets. This research provides both theoretical and practical foundations for the development of green and efficient preservation technologies for tilapia products.