## 2 Materials and Methods
### Study by \({}^{1}h\) NMR of Oil Samples and Lipid Extracts of Digestates
#### 2.4.3 Quantifications from \({}^{1}\)H NMR Spectral Data
(C) Estimation of the Concentration of Specific Compounds (SC) in Oil Samples and in the Digestates  
The concentration of oxidation compounds, and of others, such as gamma-tocopherol, cycloartenol plus 24-methylencycloartenol, dodecyl gallate, and hydroxytyrosol acetate, either in oils or digestates, can be estimated using the Equation S12, given in Supplementary Material, using the intensity of one of their nonoverlapped \({}^{1}\)H NMR spectral signals, which are indicated in Figures 1 and 2, and in Tables S3, S4, and S5. This equation allowed us to estimate the concentration of any compound in oils or in digestates in relation to the concentration of fatty acids plus acyl groups, which are considered the internal reference. Study by SPME-GC/MS of the Headspace of Digestates and of the Mixture of the Digestive Jucices Submitted to Digestion Conditions with the Virgin Flaxseed Oil  
The extraction of the volatile components constituting the headspace of the several samples (0.5 g in a 10 mL screw-cap vial) was accomplished automatically using a CombiPAL autosampler (Agilent Technologies, Santa Clara, CA, USA). The samples studied were the several digestates (DE, DFDG\({}_{1}\), DFDG\({}_{2}\), DFHTA\({}_{1}\), DFHTA\({}_{2}\), DFyT\({}_{1}\), DFyT\({}_{2}\), DFyT\({}_{3}\), and DFyT\({}_{4}\)) and a mixture FDJ of digestive juices DJ, after undergoing digestion conditions, and virgin flaxseed oil F. The comparison of the headspace of the several samples enabled us to deduce the changes brought about by in vitro digestion. The fiber used for the extraction of the headspace components was coated with Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS, 50/30 \(\upmu\)m film thickness, 1 cm long, and acquired from Supelco (Sigma-Aldrich, St. Louis, MO, USA)). It was inserted into the headspace of the sample and maintained for 55 min at 50 \({}^{\circ}\)C, after a pre-equilibration time of 5 min. The fiber containing the components extracted was desorbed for 10 min in the injection port (splitless mode with 5 min purge time) of a 7890A gas chromatograph equipped with a 5975C inert MSD with Triple Axis Detector (Agilent Technologies, Palo Alto, CA, USA) and a computer operating with the ChemStation program. A fused silica capillary column was used (60 m length, 0.25 mm internal diameter, 0.25 \(\upmu\)m film thickness; from Agilent Technologies Inc., Palo Alto, CA), coated with a nonpolar stationary phase (HP-5 MS, 5%phenyl methyl siloxane). The operating conditions were as follows: the injector and interface temperatures were held at 250 \({}^{\circ}\)C and 305 \({}^{\circ}\)C respectively, and helium at a constant pressure of 117 kPa (16.9 psi) was used as the carrier gas. The oven temperature was initially held at 50 \({}^{\circ}\)C for 5 min, increased from 50 \({}^{\circ}\)C to 300 \({}^{\circ}\)C at a rate of 4 \({}^{\circ}\)C/min, and then held at 300 \({}^{\circ}\)C for 30 min. Mass spectra were recorded at an ionization energy of 70 eV, with data acquisition in Scan mode. The temperatures of the ion source and the quadrupole mass analyzer were kept at 230 \({}^{\circ}\)C and 150 \({}^{\circ}\)C, respectively. A reference sample of known composition was periodically analyzed in order to verify the sensitivity of the SPME-GC/MS experiments, as in previous studies [34]. Identification of the headspace components was carried out using several commercial standard compounds acquired from Sigma-Aldrich (St. Louis, MO, USA). When standard compounds were not available, the identification was performed by matching the spectra obtained, higher than 85%, with those of commercial libraries (Wiley W9N08, Mass Spectral Database of the National Institute of Standards and Technology), or with spectra provided by the scientific literature, as in previous studies [34]. The semiquantification of the compounds was based on the area counts of the base peak (Bp) of the mass spectrum of each compound divided by \(10^{6}\).