# Utilization of Yacon Damaged Roots as a Source of FOS-Enriched Sweet-Tasting Syrup
## 2 Materials and Methods
### Chemical Composition
#### 2.4.2 Carbohydrate Composition  
The neutral sugars composition of EtSn and EtRe was determined following the Saeman acid hydrolysis, reduction, and acetylation steps for the conversion of the monosaccharides to alditol acetates. Gas chromatography with a flame ionization detector (GC-FID, Perkin Elmer-Claus 400, PerkinElmer Inc., Shelton, CT, USA) equipped with a DB-225 (J&W Scientific-Agilent Technologies, Santa Clara, CA, USA) column was used for quantification purposes. 2-deoxyglucose was used as an internal standard [22]. The \(m\)-Phenylphenol method was used to determine colorimetrically the uronic acids (UA) [23].  
The free glucose (Glc) and fructose (Fru), sucrose (Suc), fructoligosaccharides (FOS), and inulin content in the syrup samples were determined by high-performance anion-exchange chromatography/pulsed amperometric detection (HPAEC-PAD) using a Dionex ICS-600 system equipped with a DC oven and SP, controlled by Chromeleon 7.3 software (Thermoscientific Dionex - Waltham, MA, USA). Carbohydrates were detected using an electrochemical detector in integrated amperometry mode with an AgCl reference electrode and a conventional electrode. The carbohydrate separation was performed using a Dionex CarboPac PA100 pre-column (50 mm \(\times\) 4 mm) and a Dionex CarboPac PA100 analytical column (250 mm \(\times\) 4 mm). The eleuents used were eluent A--MilliQ water (resistance of \(\approx\)18 M\(\Omega\).cm), eluent B--500 mM NaOH (prepared from a 50% sodium hydroxide solution, MERCK), and eluent C--1 M sodium acetate (sodium acetate, Thermo Scientific(tm) Dionex(tm)-Waltham, MA, USA) with 100 mM NaOH. The eleuents were filtered through a 0.2 nylon filter um and degassed under vacuum with sonication for 30 min. Afterwards, the eleuents were transferred to 2 L Thermo Fisher Dionex plastic bottles and placed under a nitrogen atmosphere. The column and detector temperatures were 30 \({}^{\circ}\)C. The initial equilibrium was performed with 12.0% solvent B and 0.5% solvent C. After injecting 25 \(\upmu\)L of sample into the column, the compounds were eluted at a flow rate of 1 mL.min\({}^{-1}\) by the following method: An initial step of A:B:C 87.5:12.0:0.5 (\(v/v/v\)) for 5 min; a gradient from 87.5:12.0:0.5 to 61:24:15 from 5 to 50 min; followed by a 0:25:75 gradient from 50 to 105 min. After a gradient of 0:0:100 for 5 min, kept for 10 min to remove impurities,the eluent proportion was returned to the initial conditions and held for an equilibration time of 20 min. Glc, Fru, Suc, kestose, kestotetraose, inulotriose, and kestopentaeose were used as standards for quantification. FOS solely composed of Fru units (inulo-type FOS) were quantified as inulotriose equivalents. FOS containing the sucrose unit (kesto-type FOS), presenting a degree of polymerization (DP) between 5-9, and inulins (DP \(\geq\) 10) were quantified as kestopentaeose equivalents. The FOS and inulin average degree of polymerization (DP) was determined by accounting for the sum of the product between the relative proportion of each FOS/inulin and the respective DP.  
To determine other polysaccharides composing the polymeric material, yacon syrups were dialyzed with a cut-off membrane of 12 kDa (Medicell). Before dialysis, syrup samples were previously diluted in water and centrifuged at 20,000\(\times\)\(g\) (Thermo Scientific Multifuge X1R) for 10 min for the removal of particulate material. The polymeric material of the syrups was freeze-dried and subjected to neutral sugar and uronic acid analysis.