A Time-Resolved PTR-ToF-MS Workflow for Characterizing Opening-Burst Volatile Features in Canned Antarctic Krill...

Volatile release immediately after opening canned foods is highly transient and may not be adequately represented by equilibrium or quasi-equilibrium headspace measurements. In this study, time-resolved proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) was used to characterize opening-burst volatile features in canned Antarctic krill processed to an equivalent sterilization intensity (F₀ ≈ 9 min). Raw krill, pretreated but non-retorted samples, and samples retorted using different temperature-time combinations were monitored online for 180 s after opening, with particular attention to the 0-60 s burst phase. Twenty-three of the twenty-five retained features reached their maximum responses within 10 s, including two within 5 s, showing that the dominant volatile changes occurred immediately after opening. The maximum background-corrected response during 0-60 s (C_max,0-60) and the corresponding area under the response curve (AUC_0-60) were used to describe transient release. The nine highest-ranked features accounted for 76.78% of the cumulative AUC_0-60 response within the retained candidate feature set. Although the retort treatments had similar F₀ values, their burst-phase fingerprints remained distinguishable. Sulfur-associated features varied markedly among treatments, whereas several low-molecular oxygenated features showed strong responses after the 121 °C high-temperature/short-time treatment. These findings show that the first seconds after opening contain substantial volatile-release information and that equivalent sterilization lethality does not necessarily produce the same opening-burst fingerprint. Time-resolved PTR-ToF-MS therefore enables direct examination of the initial post-opening volatile environment and comparison of different thermal processing routes. Chemical names are reported as putative annotations rather than definitive identifications.