Effects of plasma-activated lactic acid on the physicochemical properties and volatile organic compounds of refrigerated tilapia fillets

This study developed a novel plasma-activated lactic acid (PALA) strategy (650 W, 90 s, 0.0625 % lactic acid) to preserve refrigerated tilapia fillets. Mechanistically, PALA-generated reactive nitrogen species, particularly •NO₃/•NO₂, effectively stabilized pH and inhibited microbial proliferation, maintaining counts at 6.41 Log CFU/g and TVB-N at 15.26 mg/100 g after 7 days of storage. The synergy between acid and reactive oxygen nitrogen species significantly delayed lipid oxidation (TBARS reduced by >40 %) and protein degradation, preserving texture and color. PALA suppressed myofibrillar protein (MP) oxidation, reducing carbonyls and surface hydrophobicity by 52 % and 20 %, respectively, while increasing sulfhydryl content by 53 %, as confirmed by SDS-PAGE showing attenuated myosin/actin degradation. Volatile profiling revealed PALA reduced spoilage aldehydes (heptanal, nonanal) while retaining fresh-flavor aldehydes (octanal, dodecanal). This multi-target action extended the shelf life by 4 days, with nitrate/nitrite residues within safety limits, establishing PALA as an innovative, synergistic preservation technology for aquatic products. • PALA extended tilapia shelf life by 4 d via inhibiting microbial growth. • PALA delayed lipid/protein oxidation with lower TBARS and TVB-N. • PALA reduced MP carbonyls and surface hydrophobicity, preserving protein integrity. • PALA improved flavor by suppressing spoilage aldehydes and retaining fresh compounds.