The chemical composition, encompassing free sugars and organic acids was evaluated following procedures previously described by Barros et al. [20 (link)].
Free sugars were analyzed by HPLC coupled to a refraction index detector (Knauer, Smartline system 1000). The compounds were identified by chromatographic comparisons with authentic standards (D(−)-fructose, D(+)-sucrose, D(+)-glucose, D(+)-trehalose, and D(+)-raffinose pentahydrate) which were purchased at Sigma-Aldrich (St. Louis, MO, USA), as also melezitose (PanReac AppliChem ITW Reagents Co., Darmstadt, Germany) which was applied as the internal standard (IS) and used in the quantification method. Data was analyzed using Clarity 2.4 software (DataApex, Podohradska, Czech Republic), and the results were expressed in g/100 g fw.
Organic acids were evaluated using an Ultra-Fast Liquid Chromatography (UFLC, Shimadzu 20A series, Kyoto, Japan) coupled to a diode array detector. Organic acids standards (L(+)-ascorbic acid, citric acid, malic acid, oxalic acid, shikinic acid, succinic acid, fumaric acid, and quinic acid; Sigma-Aldrich, St. Louis, MO, USA) were used for identification by performing chromatographic comparisons with the peaks of the samples. These standards were also used for quantification relying on the external standard methodology. Results were expressed g/100 g fw.
Free sugars were analyzed by HPLC coupled to a refraction index detector (Knauer, Smartline system 1000). The compounds were identified by chromatographic comparisons with authentic standards (D(−)-fructose, D(+)-sucrose, D(+)-glucose, D(+)-trehalose, and D(+)-raffinose pentahydrate) which were purchased at Sigma-Aldrich (St. Louis, MO, USA), as also melezitose (PanReac AppliChem ITW Reagents Co., Darmstadt, Germany) which was applied as the internal standard (IS) and used in the quantification method. Data was analyzed using Clarity 2.4 software (DataApex, Podohradska, Czech Republic), and the results were expressed in g/100 g fw.
Organic acids were evaluated using an Ultra-Fast Liquid Chromatography (UFLC, Shimadzu 20A series, Kyoto, Japan) coupled to a diode array detector. Organic acids standards (L(+)-ascorbic acid, citric acid, malic acid, oxalic acid, shikinic acid, succinic acid, fumaric acid, and quinic acid; Sigma-Aldrich, St. Louis, MO, USA) were used for identification by performing chromatographic comparisons with the peaks of the samples. These standards were also used for quantification relying on the external standard methodology. Results were expressed g/100 g fw.