Dp 8020 pump

Specific rotations were measured using a DIP-360 digital polarimeter (JASCO, Easton, PA, USA). Nuclear magnetic resonance (NMR) spectra were recorded on a JEOL ECX 400 FT-NMR spectrometer (JEOL, Tokyo, Japan) at room temperature. Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) experiments were performed using a Waters Xevo G2-XS Q-TOF mass spectrometer (Waters, Milford, MA, USA). Column chromatography was performed on Silica Gel 60 (Nacalai Tesque, Kyoto, Japan, 230–400 mesh) and YMC ODS-A gel (YMC Co. Ltd., Kyoto, Japan, 50 µm). Thin-layer chromatography (TLC) was performed on TLC Silica Gel 60F254 (Merck, Damstadt, Germany) and TLC Silica Gel 60 RP-18 F254S (Merck, Damstadt, Germany) plates. The spots were visualized by spraying with 10% aq. sulfuric acid followed by heating. High-performance liquid chromatography (HPLC) was performed using a UV-8020 UV-VIS detector (Tosoh Corp., Tokyo, Japan), DP-8020 pump (Tosoh Corp., Tokyo, Japan), and DP-8020 degasser (Tosoh Corp., Tokyo, Japan). An XBridge BEH C18 Column (Waters, Milford, MA, USA, 130 Å, 3.5 µm, 10 mm × 250 mm) was used for preparative purposes.

Rice flour samples (20 mg) were suspended in 1.6 mL of distilled water in a 15 mL centrifuge tube and gelatinized with 400 µL of 5 M NaOH for 30 min at 37 °C. Then, 2 mL of distilled water and 2 mL of eluent (0.2% NaCl/0.05 M NaOH) were added to each sample, followed by filtration through a 5 µm Durapore polyvinylidene fluoride (PVDF) membrane (Merck, Darmstadt, Germany). A 5 mL aliquot of the filtrate was used in a 4-column system (Toyopearl HW75S × 2-HW65S-HW55S; 2.2 cm diameter, 30 cm × 4; Tosoh Corp., Tokyo, Japan) that was pre-equilibrated with the eluent, and carbohydrates were detected using an RI detector (RI-8020; Tosoh Corp.). The columns were incubated at 40 °C, and the samples were eluted at a flow rate of 1 mL/min using a DP-8020 pump (Tosoh Corp.).