## Materials and Methods
### Chemical Composition  
Physicochemical analyses were performed according to methods established by the Association of Official Analytical Chemists [38] as follows: pH was determined using pH meter, tittatable acidity was determined by titration with 0.1 N NaOH, and total soluble solid was determined using a digital refractometer.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Name** & **Inulin (\%)** & **Bocaitiva Powder-Pulp (\%)** \\ \hline CONT & - & - \\ IN3.5 & 3.5 & - \\ BO3.5 & - & 3.5 \\ BO7.0 & - & 7.0 \\ BO + IN & 3.5 & 3.5 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Treatment of kefir-fermented soymilk.  
Vitamin C content was determined using oxalic acid, dichlorophenol indophenol (DCFI), and a standard ascorbic acid solution as the extracting solvent, as described by [PERSON] and [PERSON] [39]. Briefly, 5 g of the sample was homogenized in 50 mL oxalic acid 2% and filtered through Whatman No. 4 filter paper. A total of 10 mL of aliquots were titrated with 0.2% dichlorophenol-indophenol. Results were expressed as milligrams of reduced ascorbic acid per 100 g of sample.  
Carotenoid content was determined by extracting 5 g of the macerated sample and 3 g of celite with 30 mL of acetone and filtering the sample. This extract was mixed with 50 mL of petroleum ether and placed in a separating funnel, and the mixture was washed with distilled water three times. The lower phase (water) was discarded, and the upper phase was collected and mixed with anhydrous sodium sulfate. The volume was adjusted to 25 mL, and the absorbance was read on a spectrophotometer at 450 nm [40].  
The crude extract used to determine total phenolic compounds and antioxidant activity was determined according to the method described by [PERSON] et al. [41]. Briefly, 1 g of the sample was homogenized with 40 mL of 50% methanol and incubated in the dark for 60 min. Then, the mixture was filtered and the supernatant was transferred to a 100 mL volumetric flask. The residue from the first extraction was mixed with 40 mL of 70% acetone and incubated in the dark for 60 min. The mixture was filtered, the supernatant was combined with the first extraction, and the volume was adjusted to 100 mL with distilled water.  
Total phenolic compounds were determined by mixing 200 \(\mu\)L of the prepared crude extract with 1.9 mL of Folin-Ciocalteu reagent diluted 10 fold with distilled water and 1.9 mL of aqueous sodium carbonate (Na\({}_{2}\)CO\({}_{3}\)) solution. After incubation for 120 min in the dark, the absorbance was measured at 725 nm using ferulic acid as a standard. The results were expressed in grams of ferulic acid equivalents per gram of sample.  
Antioxidant activity was determined using the ABTS and DPPH methods. The DPPH method was performed as described by [PERSON] et al. [42], with the modifications reported by [PERSON] et al. [43]. Briefly, a 0.1 mL aliquot was mixed with 3.9 mL of DPPH radical (0.06 mM). Methyl alcohol was used as a blank to calibrate the spectrophotometer and as a control. Absorbance was determined at 515 nm.  
In the ABTS assay, ABTS radical cations (ABTS\(\bullet\)+) were generated in the reaction between 5 mL ABTS aqueous solution (7 mM) and 88 mL potassium persulfate solution (140 mM) to reach the final concentration of 2.45 mM. The mixture was left in the dark for 14 h at room temperature and diluted with ethanol until absorbance of 0.7 \(\pm\) 0.02 at 734 nm. Sample extracts (30 mL) were added to 3 mL ABTS radical solution in the dark, and absorbance was measured at 734 nm after 6 min.  
The results of the ABTS and DPPH assays were expressed as \(\mu\)M TEAC (Trolox equivalent antioxidant capacity) per 100 g of sample.