A Shimadzu ion exclusion column (Shim-pack SCR-101H,
7.9 mm × 30 cm) was operated at 30 °C for carbohydrates and alcohols
and 50 °C for acids. Perchloric acid (100 mM)was used as the eluent at a
flow rate of 0.6 mL/min. The acids were detected via UV absorbance
(210 nm), while the alcohols and carbohydrates were detected via RID
(Miguel, Santos, Duarte, Almeida, & Schwan, 2012). All samples were analyzed
in triplicate, and individual compounds were identified based on
the retention time of standards injected using the same conditions. The
sample concentrations were determined using an external calibration
method. Calibration curves were constructed by injecting different concentrations
of the standards under the same conditions of sample analysis
and the areas obtained were plotted a linear curve whose equation
was used to estimate the concentration of the compounds in the sample.