*2.2. Characterization of Simple Sugars by HPLC-Refractive Index*

The simple sugars profile was measured as described by Heredia-Olea et al. [30] and Alonso-Gómez et al. [31] with slight modifications. The samples were filtered through a polyvinylidene fluoride (PVDF) syringe filter (0.2 µm) and injected into high-performance liquid chromatography (HPLC) equipment (Waters HPLC Breeze model, Waters, Milford, MA, USA) with a refractive index detector

(Waters 2414) kept at 50 ◦C. The chromatographic separation was achieved using an ion-exclusion column Phenomenex Rezex ROA-organic acid h+ (250 × 4.6 mm, 8 µm particle size, Phenomenex, Torrance, CA, USA) at 60 ◦C. The mobile phase consisted of a 5 mM H2SO<sup>4</sup> solution with a 20 min isocratic flow rate of 0.4 mL min−<sup>1</sup> and with an injection volume of 10 µL. Glucose, maltose, and fructose quantifications were performed with calibration curves of HPLC-grade standards (Sigma-Aldrich, St. Louis, MO, USA).

Calibration curves for glucose (1–25 mg mL−<sup>1</sup> ), maltose (0.5–5 mg mL−<sup>1</sup> ), and fructose (1–25 mg mL−<sup>1</sup> ) of HPLC-grade standards (Sigma-Aldrich, St. Louis, MO, USA) were constructed for quantification purposes (data not shown).
