Rezex rcm monosaccharide

The analysis was performed on the Thermo Finnigan Surveyor HPLC system equipped with an IR (infrared) detector for sugar analysis and UV (ultraviolet/visible light) detector for organic acids. (Thermo Scientific, San Jose, CA, USA). For sugars, a Rezex RCM monosaccharide (30 × 0.78 cm; Thermo Scientific, San Jose, CA, USA) column and for organic acids and ascorbic acid Rezex ROA an organic acid column (30 × 0.78 cm; Phenomenex, Torrance, CA, USA) were used. Both columns were heated to 65 °C, except for ascorbic acid where the column was heated to 25 °C. The adjustment of the HPLC system was based on Zamljen, et al. [12 (link)]. For the analysis of sugars an isocratic method was used with the mobile phase consisting of bidistilled water. For the analysis of organic acids and ascorbic acid an isocratic method was used with the mobile phase consisting of 4 mM H₂SO₄ in bidistilled water. The results were expressed in g/kg dry weight (DW) for sugars, organic acids and ascorbic acid. The chromatographic data for sugars are presented in Figure S1 and chromatographic data for organic acids are presented in Figure S2A. The chromatographic data for ascorbic acid are presented in Figure S2B.

For extraction of sugars and organic acids, 0.05 g of powder was weighed and poured over with 2 ml of bidistilled water. Only edible parts (pericarp and placenta) were used for total sugars and organic acids analysis. Samples were then shaken on an orbital shaker for 30 min. After shaking, they were placed in a cooled centrifuge in which the samples were rotated at 10,000 rpm for 8 min. Samples were filtered through 25 µl cellulose filters (Chromafil A-25/25; Macherey–Nagel, Düren, Germany) and saved at – 20 °C until analysis on the Thermo Finnigan Surveyor HPLC system (Thermo Scientific, San Jose, USA). Two columns were used for the analysis: for sugars (Rezex RCM-monosaccharide (30 × 0.78 cm; Thermo Scientific, San Jose, USA)) and for organic acids (Rezex ROA organic acid column (30 × 0.78 cm; Phenomenex, Torrance, USA). Extraction method and HPLC settings were based on Zamljen et al.^{12 (link)} The results are reported in g/kg dry weight (DW) for sugars, citric, malic and quinic acid and in mg/100 g DW for succinic, fumaric and oxalic acid. All sugars and organic acids (including ascorbic acid) were determined only in edible parts (pericarp and placenta).