## 3 Results
### XANES  
XANES spectra of the fruit, pericarp, and seeds were measured around the sulfur K-edge, and the results are shown in Figures 1-3 [16], respectively.  
Figure 1: Sulfur K-edge XANES spectra of the _Bixa orellana_ fruit (Sample 1). Linear Combination Fitting and components are plotted together with experimental data.  
Figure 2: Sulfur K-edge XANES spectra of the _Bixa orellana_ pericarp (Sample 2). Linear Combination Fitting and components are plotted together with experimental data.  
The three spectra have a strong resemblance in shape, with three characteristic features around 2471 eV, 2474 eV, and 2480 eV. Intensity differences are observed in the main features from one spectrum to the other. With the objective of determining the sulfur functional groups that account for each feature, the sulfur K-edge spectrum of reference compounds was measured in identical experimental conditions for a set of standards covering the main functional groups of sulfur in different oxidation states. These spectra were then used to perform a best fit analysis of the sample spectra. Spectral compositions were determined using a Linear Combination Fitting technique in ATHENA [23] software. The best fit was determined by fitting several combinations of standards and choosing the combination that provided better fitting parameters; these combinations were achieved using the same software algorithm. When more than one standard with the same sulfur functional group was available, the fitting was tested by changing the standards to determine which standard better fitted the spectra. The set of standards comprised reference compounds including thiols (as cysteine and reduced glutathione), thioether (as methionine), disulfide (as cysteine and oxidized glutathione), sulfoxide (as dimethyl sulfoxide), sulfone (as L-methionine sulfone), sulfonic acid (as cysteic acid), organic sulfate (as chondro sulfate), and inorganic sulfate (as zinc sulfate), measured under the same conditions. The contribution of these functional groups to each spectrum and the standard used in the fitting are presented in Table 2[16].  
For all three spectra, the feature at 2480 eV is the most intense and is explained by the presence of at least two highly oxidized groups: inorganic sulfate and sulfonic acid. The feature at 2474 eV indicates the predominance of one intermediate oxidized species,  
\begin{table}
\begin{tabular}{l l c c c c} \hline \hline
**Compound** & **Functional Group** & **Oxidation State**[26; 27; 28] & **Sample 1** & \multicolumn{2}{c}{**Sample 2**} \\ \hline  & & & **Whole Fruit** & **Pericarp** & **Seed** \\  & & **\%** & **\%** & **\%** & **\%** \\ \hline Oxidized glutathione & disulfide & 0.2 & 12.9 \(\pm\) 2.0 & 6.6 \(\pm\) 2.4 & 18.2 \(\pm\) 1.7 \\ Methionine & thioether & 0.5 & 18.2 \(\pm\) 1.8 & 14.9 \(\pm\) 2.2 & 24.8 \(\pm\) 1.6 \\ DMSO & sulfoxide & 2 & 10.2 \(\pm\) 0.7 & 8.6 \(\pm\) 0.9 & 11.0 \(\pm\) 0.5 \\ Cysteic acid & sulfonic acid & 5 & 9.6 \(\pm\) 0.5 & 9.3 \(\pm\) 0.6 & 3.1 \(\pm\) 0.5 \\ Inorganic sulfate & inorganic sulfate & 6 & 48.2 \(\pm\) 0.5 & 61.0 \(\pm\) 0.6 & 43.0 \(\pm\) 0.5 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Results of LCF of _Bixa orellana_ fruit, pericarp, and seeds.  
Figure 3: Sulfur K-edge XANES spectra of _Bixa orellana_ seeds (Sample 2). Linear Combination Fitting and components are plotted together with experimental data.  
such as a sulfoxide group. Finally, in the feature at 2471 eV, contributions from thioether (methionine) and disulfide (oxidized glutathione) were observed in all spectra.