## 3 Results and Discussion
### Polyphenolic Profile by UPLC-ESI-MS Analysis
Peaks 7 (Rt = 15.82 min) and 25 (Rt = 24.76 min) correspond to methyl-6-gingerol and methyl-8-gingerol, respectively, based on the adduct [M+Na]\({}^{+}\) at m/z 331.1985 (C\({}_{18}\)H\({}_{28}\)O\({}_{4}\)Na) and 359.2364 (C\({}_{20}\)H\({}_{32}\)O\({}_{4}\)Na), and the presence of the dehydrated form [M+H-H\({}_{2}\)O]\({}^{+}\) at m/z 291.1988 and 319.2360. The MS2 spectrum of methyl gingerols reveals a fragmentation pattern similar to gingerols with fragments at m/z 191 and 151 (Figure 4) [11]. The third group is composed by shogaols, compounds that correspond to the dehydrated form of gingerols, conversion that is mainly produced at higher temperature [25]. Among shogaols, peaks 11 (Rt = 18.27 min), 20 (Rt = 23.34 min) and 28 (Rt = 27.94 min) present pseudomolecular ions [M+H]\({}^{+}\) at m/z 277.1795 (C\({}_{17}\)H\({}_{25}\)O\({}_{3}\)), 305.2117 (C\({}_{19}\)H\({}_{29}\)O\({}_{3}\)) and 333.2430 (C\({}_{21}\)H\({}_{33}\)O\({}_{3}\)) and were tentatively assigned to 6-shogol, 8-shogol and 10 shogol, respectively. The breaking of the benzyl bond produces the fragment seen at m/z 137 (Figure 5) [24]. Another group of compounds are gingerdiols, the ketone reduction products of gingerols [11]. Gingerdiols present two hydroxyl groups (\(-\)OH groups) that dehydate and provide adducts [M+H-2(H\({}_{2}\)O)]\({}^{+}\) and [M+H-H\({}_{2}\)O]\({}^{+}\), the first one being the predominant  
Figure 4: Fragmentation pathway for methylgingerol compounds 7 (\(n=6\)), 25 (\(n=8\)). Figure 5: Fragmentation pathway for shogol compounds 11 (\(n=6\)), 20 (\(n=8\)), 28 (\(n=10\)). Figure 3: Fragmentation pathway for gingerol compounds 1 (\(n=4\)), 3 (\(n=6\)), 10 (\(n=8\)), 23 (\(n=10\)), 30 (\(n=12\)). adduct for peaks 6 (Rt = 15.72 min) and 17 (Rt = 21.23 min) at m/z 289.2173 (C\({}_{19}\)H\({}_{29}\)O\({}_{2}\)) and 317.2378 (C\({}_{21}\)H\({}_{33}\)O\({}_{2}\)), respectively, corresponding to 8-gingerdiol (C\({}_{19}\)H\({}_{32}\)O\({}_{4}\)) and 10-gingerdiol (C\({}_{21}\)H\({}_{36}\)O\({}_{4}\)). These peaks present likewise the adducts [M+H-H\({}_{2}\)O]\({}^{+}\) at m/z 307.2273 and 335.2504, and [M+Na]\({}^{+}\) at m/z 347.2245 and 375.2632, respectively. Peak 2 (Rt = 11.71 min) presents an adduct [M+H-H\({}_{2}\)O]\({}^{+}\) at 279.1975 (C\({}_{17}\)H\({}_{27}\)O\({}_{3}\)) and was tentatively identified as 6-gingerdiol (C\({}_{17}\)H\({}_{28}\)O\({}_{4}\)), also showing adducts [M+H-2(H\({}_{2}\)O)]\({}^{+}\) and [M+Na]\({}^{+}\) at m/z 261.1873 and 319.1875, respectively. Gingerdiols did not fragment via C4-C5 cleavage, which may indicate that the ketone group on C-3 is critical for the fragmentation pathway [24]. The main fragments found were due to dehydration and the fragment at m/z 137 corresponds to the benzyl moiety (Figure 6). A related group corresponds to dehydrogingerdiones. Peaks 19 (Rt = 22.53 min), 27 (Rt = 27.37 min) and 34 (Rt = 31.37 min) were tentatively identified as 1-dehydro-6-gingerdione, 1-dehydro-8-gingerdione and 1-dehydro-10-gingerdione with a pseudo-molecular ion [M+H]\({}^{+}\) at m/z 291.1494 (C\({}_{17}\)H\({}_{23}\)O\({}_{4}\)), 319.1909 (C\({}_{19}\)H\({}_{27}\)O\({}_{4}\)) and 347.220 (C\({}_{21}\)H\({}_{31}\)O\({}_{4}\)), respectively. These dehydrogingerdiones present a double bond between C1 and C2, yielding a fragment ion at m/z 177 due the keto group on the alkyl chain that causes fragmentation on the protonated molecules (Figure 7) [24]. In turn, the group of acetoxy gingerols includes peaks 12 (Rt = 18.42 min), 21 (Rt = 23.40 min) and 29 (Rt = 27.99 min) with sodium adduct ions [M+Na]\({}^{+}\) observed at m/z 359.1815 (C\({}_{19}\)H\({}_{28}\)O\({}_{5}\)Na), 387.2239 (C\({}_{21}\)H\({}_{32}\)O\({}_{5}\)Na) and 415.2560 (C\({}_{23}\)H\({}_{36}\)O\({}_{5}\)Na) respectively, corresponding to acetoxy-6-gingerol, acetoxy-8-gingerol and acetoxy-10-gingerol.