## 2 Material and Methods
### Biochemical Analysis
#### 2.6.2 Biogenic Amines Measurement  
Ten milliliters of the stomached solution (see Section 2.3) was mixed with 5 mL of a trichloroacetic acid solution at 12% (Panreac, Darmstadt, Germany). The samples were kept frozen at \(-20\)\({}^{\circ}\)C until analysis. Eight biogenic amines (tryptamine, 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, spermine) were quantified using high-pressure liquid chromatography (HPLC) following [PERSON] et al. 's [40] methodology. 6.3 Headspace-Solid-Phase Microextraction (HS-SPME) and Gas Chromatography/Mass Spectrometry (GC/MS) Analysis of the Volatilome  
For each sampling date for the 3 products, portions of 20 g were withdrawn and stocked under VP at \(-40\)\({}^{\circ}\)C. Eight salmon flesh cylinders were sampled across the frozen product using a pre-cooled metal cork borer and immediately pooled to make up 1 g of an analysis sample. Samples were kept frozen in 4 mL vials with a screw cap and PTFE/silicone septum at \(-40\)\({}^{\circ}\)C prior to extraction and analysis. For each sample (time point and treatment), 3 independent analysis samples (triplicate) were prepared. Prior to the volatile extraction, a \(30\%\)\(w/v\) NaCl solution (H\({}_{2}\)O) was added to the sample, which was finally minced using a high-speed homogenizer. HS-SPME was applied for the extraction of VOCs using a manual SPME holder with a PDMS/DVB-coated 65 \(\upmu\)m fiber (Supelco Inc., Bellefonte, PA, USA). Prior to the extraction, the SPME fiber was conditioned in the injection port of the GC according to the instructions provided by the supplier. The SPME fiber was exposed to the atmosphere in the closed sample vial for 30 min while keeping the vial in an isothermal condition at 50 \({}^{\circ}\)C in a water bath. Samples were constantly agitated using a magnetic stirrer during extraction. An Agilent 6890/5975 GC/MS (Agilent Technologies Inc., Palo Alto, CA, USA) was used for all analyses. Analytes absorbed on the SPME fiber were desorbed in the injection port for 3 min under splitless conditions. GC separations were carried out using an apolar HP-5 MS capillary column (30 m \(\times\) 0.25 mm and film thickness 0.25 \(\upmu\)m). The injection temperature was 220 \({}^{\circ}\)C and the interface was set to 220 \({}^{\circ}\)C. The carrier gas was He at a constant flow rate of 1 mL/min. The GC temperature was ramped from 40 to 211 \({}^{\circ}\)C at a rate of 4.5 \({}^{\circ}\)C/min, then raised at a rate of 50 \({}^{\circ}\)C/min and finally held at 220 \({}^{\circ}\)C (total run time: 40 min). The MS source was adjusted to 230 \({}^{\circ}\)C and a mass range of \(m/z\) 35-350 was recorded. Mass spectra were acquired in electron impact ionization (EI) mode at 70 eV. GC/MS chromatograms were visualized using the following GC/MS software packages: Agilent ChemStation software (Agilent Technologies, Waldbronn, Germany), AMDIS software (version 2.71; National Institute of Standards and Technology, Boulder, CO, USA) and the open-source program OpenChrom Community Edition Alder (version 1.2.0) (Lablicate GmbH, Hamburg, Germany; [[https://lablicate.com/platform/openchrom](https://lablicate.com/platform/openchrom)]([https://lablicate.com/platform/openchrom](https://lablicate.com/platform/openchrom)))(accessed on 10 August 2021). Tentative identification of compounds was carried out using (a) MS libraries, such as NIST05 spectral library (National Institute of Standards and Technology, Gaithersburgh, MD), the NIST Chemistry WebBook ([[https://webbook.nist.gov/chemistry](https://webbook.nist.gov/chemistry)]([https://webbook.nist.gov/chemistry](https://webbook.nist.gov/chemistry)))(accessed on 10 August 2021) and a customized in-house MS library of VOCs; in combination with (b) linear retention indices (LRI), based on a homologous series of even-numbered n-alkanes (C8 to C24); and (c) LRIs found in the literature and the NIST Chemistry WebBook.