1 1 kestotetraose

Carbohydrate analysis via high-performance anion exchange chromatography (HPAEC) was performed to determine inulin profiles, and to quantify glucose, fructose, sucrose, 1-kestotriose, 1,1-kestotetraose and 1,1,1-kestopentaose. Measurements were operated on a Dionex ICS-3000 system with the Chromeleon 6.60 software (all components from Dionex). The extraction of total soluble carbohydrates was described in detail by Kusch et al. (2009) (link). In brief, aliquots of the final supernatant were dried in a speedvac concentrator (Bachofer, Reutlingen, Germany). Subsequently, sugar pellets were dissolved in HPLC water (VWR Prolabo) to 10 mg/ml. Final sugar concentration of 0.2 mg/ml and 0.5 mg/ml for taproot and shoot organs respectively were subjected to carbohydrate analysis via HPAEC-PAD. For peak identification, glucose (Merck, Darmstadt, Germany), fructose (Applichem), sucrose (Applichem), 1-kestotriose, 1,1-kestotetraose, 1,1,1-kestopentaose (all Wako Chemicals) and RaftilineST (Orafti, Tienen, Belgium) were used as external standards.

Total soluble carbohydrates were extracted as described by Wei et al. [42 (link),43 (link)]. Quantification of glucose, fructose, sucrose, raffinose, stachyose, 1-kestotriose, 1,1-kestotetraose, 1,1,1-kestopentaose, and recording of profiles for inulin and levan, were performed by HPAEC-PAD as described by Wei et al. [41 (link)]. For peak identification, glucose (Merck, Darmstadt, Germany), fructose (Sigma-Aldrich), sucrose (Applichem), 1-kestotriose, 1,1-kestotetraose, 1,1,1-kestopentaose (all Wako Chemicals), raffinose (Sigma-Aldrich), and starchyose (Sigma-Aldrich) were used as standards.

The extraction of total soluble carbohydrates was described in detail by Kusch et al. (2009a (link)). Recovery rates for inulin and oligofructans ranged from 92 to 97% as determined by adding defined standard compounds before tissue extraction. Aliquots of the final supernatant were dried in a speedvac concentrator (Bachofer, Reutlingen, Germany). Subsequently, samples were dissolved in HPLC water (VWR Prolabo). High-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was performed to determine inulin profiles, and to quantify glucose, fructose, sucrose, 1-kestotriose (GF2), 1,1-kestotetraose (GF3) and 1,1,1-kestopentaose (GF4). Measurements were made with a Dionex ICS-5000 system with Chromeleon 7.2 software (all components from Dionex). For peak identification, glucose (Merck, Darmstadt, Germany), fructose (Applichem), sucrose (Applichem), 1-kestotriose, 1,1-kestotetraose, 1,1,1-kestopentaose (all Wako Chemicals) and RaftilineST (Orafti, Tienen, Belgium) were used as external standards.