Chromafil xtra mv 20 25

The extraction of organic acids and sugars was performed and analyzed according to the method described by Mikulic-Petkovsek et al. [55 (link)]. Frozen rosehips (0.5 g), from which the seeds had been previously removed, were finely crushed, and 1.5 mL of bidistilled water was added. The samples in plastic centrifuge tubes were placed on a shaker (Unimax 1010, Heidolph Instruments, Hamburg, Germany) for half an hour. The extracts were centrifuged at 10,000× g for 7 min at 4 °C (Eppendorf Centrifuge 5810 R, Hamburg, Germany). The supernatant was filtered into a labeled vial through a syringe filter (Chromafil Xtra MV-20/25, Macherey Nagel, Dueren, Germany). Until further analysis, the samples were stored in a freezer at −20 °C. The extraction was performed in triplicate. We used a UV detector set to 210 nm for separating organic acids, a Rezex ROA column (Phenomenex, Torrance, CA, USA) heated to 65 °C, and a mobile phase containing 4 mM sulfuric acid at a flow rate of 0.6 mL/min. Sugars were also separated at 65 °C on a Rezex (Phenomenex, Torrance, CA, USA) RCM monosaccharide Ca + (2%) column (300 mm × 7.8 mm). The flow rate was 0.6 mL/min continuously, 30 min total run time, and bidistilled water as the mobile phase. Carbohydrates were detected using a refractive index (RI) detector.

For the analysis of the sugars, organic acids, and phenolic compounds, the method described in previous protocols was used [16 (link),17 (link),18 (link)]. All the treatments, i.e., the various juices, were filtered using 0.2 µm cellulose filters (Chromafil Xtra MV-20/25; Macherey-Nagel, Düren, Germany) into vials for the subsequent analysis of the sugars and organic acids. For the analysis of the phenolic compounds, 0.2 µm polyamide filters (Chromafil AO-20/25; Macherey-Nagel, Düren, Germany) were used for filtration. The vials containing the filtered samples were stored at −20 °C until further analysis of the organic acids, sugars, and phenolic compounds. The ascorbic acid was extracted in a 1:1 ratio, whereby 1 mL of apple juice was mixed with 1 mL of 2% metaphosphoric acid.