## 2 Materials and Methods
### Analytical Methods
#### 2.3.2 Fatty Acids Composition  
For fatty acids (FAs) composition analysis, lipid extraction was performed with solvents after suitable preparation of the samples (WBC) according to I.D.F. [14]. The fat residue extracted was stored in amber vials, exposed to a stream of N\({}_{2}\) and frozen at \(-\)20 \({}^{\circ}\)C until analysis. Fatty acids were methylated according to [PERSON] et al. [15] with some modifications. Briefly, cheese lipid extract of 100 mg was methylated in a screw-cap Pyrex culture tube with the addition of 2 mL of 0.5 M sodium methylate at 50 \({}^{\circ}\)C for 30 min, followed by 2 mL of 140 g L\({}^{-1}\) boron trifluoride in methanol (BF3) at 50 \({}^{\circ}\)C for 30 min. Fatty acid methyl esters (FAMEs) were recovered in hexane (2 mL). Each sample (1 \(\mu\)L) was injected by Shimadzu GC-2014 GC AOC-20i autosampler into a Shimadzu gas chromatograph (model GC-17A, Columbia, MD, USA), equipped with a flame ionization detector (FID), and analyzed in duplicate. Separation of fatty acid methyl esters was achieved on a SP-2560 fused silica capillary column (75 m \(\times\) 0.18 mm I.D., 0.14 \(\mu\)m; Supelco Inc., Bellefonte, PA, USA). Helium (purity N5) was used as a carrier gas with a flow rate of 1 mL-min\({}^{-1}\) at a split ratio of 1:50 with constant flow control. The injection and detector temperatures used were 250 \({}^{\circ}\)C and 270 \({}^{\circ}\)C, respectively. The oven temperature program was as follows: the initial temperature was held at 75 \({}^{\circ}\)C for 5 min after injection, then programmed to increase at 5 \({}^{\circ}\)C/min to 150 \({}^{\circ}\)C, to hold for 5 min, and then to increase to 220 \({}^{\circ}\)C at 7 \({}^{\circ}\)C/min and hold for 20 min. Fatty acid peaks were recorded and integrated using a Shimadzu GC solution software (Shimadzu Corporation, Kyoto, Japan). Individual fatty acids were identified by their retention times and their comparison with known fatty acid methyl ester standards (Supelco 37 Component FAME Mix, purchased from Sigma-Aldrich, Taufkirchen, Germany). Amounts of fatty acids were expressed as a weight percentage of total methyl esters of fatty acid (g\(\cdot\)100 g\({}^{-1}\) of total FAMES). 3.3 Analysis of Volatile Compounds by Solid-Phase Microextraction (SPME) and Gas Chromatography-Mass Spectrometry (GC-MS)  
Volatile compounds of WBC at the 60 th, 90 th, and 180 th day of ripening were determined using solid-phase microextraction (SPME) combined with GC/MS. Cheese samples (4 g) were homogenized with 2 mL of saturated Na\({}_{2}\)SO\({}_{4}\) aqueous solution and 100 \(\upmu\)L of an internal standard (IS) aqueous solution containing 0.77 g L\({}^{-1}\) cyclohexanone (Sigma-Aldrich Quvmica, Alcobendas, Spain). Aliquots (3 g) of the homogenates were placed into 22 mL vials sealed with PTFE/silicone septa (Supelco, Bellefonte, PA, USA) through which the SPME syringe needle (bearing a 50/30 \(\upmu\)m DVB/CAR/PDMS fiber Supelco, Bellefonte, PA, USA) was introduced. The samples were stirred continuously on a stir plate revolving at 750 rpm. Fiber was exposed to the headspace above the sample for 30 min at 65 \({}^{\circ}\)C. The absorbed volatiles were immediately desorbed at 250 \({}^{\circ}\)C for 3 min, in splitless mode, into the injection port of a GC-MS system (Shimadzu GC-17 A, MS QP5050). Volatile compounds were separated by a capillary column HP-INNOWax 60 m, 0.25 mm i.d., 0.25 \(\upmu\)m film thickness (J&W Scientific, Agilent Technologies Palo Alto, CA, USA). The temperatures for the ion source, quadrupole, and interface were set at 230, 150, and 280 \({}^{\circ}\)C, respectively. The oven temperature was held at 45 \({}^{\circ}\)C for 5 min, increased to 150 \({}^{\circ}\)C at a rate of 5 \({}^{\circ}\)C min\({}^{-1}\), then raised at 7 \({}^{\circ}\)C min\({}^{-1}\) to 220 \({}^{\circ}\)C, and held at 250 \({}^{\circ}\)C for 20 min. Helium was used as carrier gas at a flow rate of 1.0 mL min\({}^{-1}\). Electron impact ionization of MS was used at a voltage of 70 eV with a scan range from 40 to 500 \(m/z\).