Sodium carbonate anhydrous

For total polyphenol index (TPI) determination, Folin–Ciocalteu reagent was purchased from Merck (Darmstadt, Germany) and anhydrous sodium carbonate was supplied by Panreac (Barcelona, Spain).
Folin–Ciocalteu reagent, anhydrous sodium carbonate, and gallic acid, for total polyphenol index (TPI) determination, were purchased from Merck (Darmstadt, Germany), Panreac (Barcelona, Spain) and Sigma-Aldrich (Saint Louis, MO, USA), respectively.
For organic acid analyses, ethylenediaminetetraacetic acid (EDTA), 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol (Bis-Tris), and trifluoroacetic acid (TFA) were purchased from Sigma-Aldrich (Saint Louis, MO, USA). Standards for calibration were supplied by Panreac (Barcelona, Spain), Sigma-Aldrich (Saint Louis, MO, USA) and Scharlab (Barcelona, Spain).
UHPLC grade acetonitrile from Panreac (Barcelona, Spain), acetic acid from Merck (Darmstadt Germany) were used to prepare the UHPLC phases. Standards for calibration were purchased from Sigma-Aldrich (Saint Louis, MO, USA). Deionized water from EMD Millipore (Bedford, MA, USA) was used to prepare the chromatography phases, reagents and standards for calibration.

Malonic acid (99% purity), anhydrous sodium carbonate and potassium iodide at commercial grade were purchased from Panreac (Barcelona, Spain). Trichloroisocyanuric acid (95% purity) was purchased from TCI Chemicals (Zwijndrecht, Belgium). Food-grade cellulose was obtained from ESSECO (San Martino di Trecate, Italy). Sodium hydroxide (97% purity), sodium phosphate monobasic (99% purity), sodium citrate, Cyt C, Lys, α-LA and BSA were purchased from Sigma Aldrich (Darmstadt, Germany). Methanol (ACS reagent), isopropanol (ACS reagent) and acetic acid (glacial) were purchased from Supelco (Bellefonte, PA, USA). Citric acid was obtained from BDH Chemicals (Poole, UK). Sodium phosphate dibasic dodecahydrate was purchased from José M. Vaz Pereira (Lisbon, Portugal).

All the used HPLC solvents were from Scharlab (Barcelona, Spain). All the used phenolic standards were from Sigma-Aldrich (Madrid, Spain), with the exception of malvidin-3-glucoside (enyn-chloride, Extrasynthese, Genay, France). Among the chemicals for spectrophotometric analysis, the Folin–Ciocalteu reagent, Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), gallic acid, and quercetin were supplied by Sigma-Aldrich (Madrid, Spain); glacial acetic acid, anhydrous sodium carbonate, and aluminum chloride 6-hydrate were supplied by PanReac AppliChem (Barcelona, Spain).

Protocatechuic acid and gallic acid were purchased from Sigma-Aldrich (Steinheim, Germany). Folin–Ciocalteu reagent, sodium carbonate anhydrous, ethyl alcohol 96%, and acetic acid glacial were purchased from PanReac AppliChem, Barcelona, Spain. All the aromatic standards were supplied by Sigma (Sigma Aldrich, Merck Life Science, Barcelona, Spain). Vanillin 99%, guaicol 98%, eugenol 98%, benzaldehyde ≥ 99%, nonenal 97%, phenylacetaldehyde ≥ 90%, phenylethyl alcohol ≥ 98%, benzyl alcohol ≥ 99%, camphor 96%, borneol 97%, 4-terpineol ≥ 96%, α-terpineol 90%, γ-nonalactone ≥ 98%, nonanoic acid ≥ 97%, vanillic acid ≥ 97%, octanoic acid ≥ 99%, dodecanoic acid 98%, benceneacetic acid ≥ 99%, furfural 99%. Dichlorometane anhydrous 99.8%, pentane anhydrous ≥ 99%, acetonitrile anhydrous ≥ 99.8%, phosphate buffered saline (PBS), potassium peroxodisulfate ≥ 99%, 6-hidroxy-2,5,7,8-tetramethyl-chromane-2-carboxylic acid 97% (Trolox), and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) were also purchased from Sigma Aldrich, Merck Life Science, Barcelona, Spain.

Methanol (Fisher Scientific, Loughborough, UK), and formic acid (Panreac, Barcelona, Spain), both high-performance liquid chromatography (HPLC) grade, were used for extraction and chromatographic analysis. Ultra-pure water was obtained from a Milli-Q water purifier system from Millipore (Bedford, MA, USA) and hydrochloric acid (Panreac, Barcelona, Spain; “for analysis” grade) was employed to adjust the pH of the solvents for the extraction.
For the anthocyanin quantification, the standard cyanidin chloride was acquired with a purity higher than 95% from Sigma–Aldrich Chemical Co. (St. Louis, MO, USA) whereas for total phenolic compounds analysis, Folin–Ciocalteu reactive (EMD Millipore, Darmstadt, Germany), sodium carbonate anhydrous (Panreac, Barcelona, Spain), and gallic acid standard ≥ 99% (Sigma–Aldrich Chemical Co., St. Louis, MO, USA) were used.

Analytical-grade reagents and purified water from a Milli-Q system (Merck, Madrid, Spain) were employed in all procedures. Sodium carbonate anhydrous, aluminum chloride 6-hydrate, sodium hydroxide pellets, and sodium nitrite were supplied by Panreac (Barcelona, Spain). Dimethyl sulfoxide (DMSO, ≥99.9%), 2 N Folin-Ciocalteu reagent, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Ethanol (EtOH), acetonitrile (ACN), methanol (MeOH), and formic acid (FA) of MS quality were provided by Scharlab (Barcelona, Spain). The phenolic standards, dihydroxy-benzoic acid (≥97.0%), caffeic acid (≥98.0%), p-coumaric acid (≥98.0%), trans-ferulic acid (98%), gallic acid monohydrate (≥98.0%), kaempferol (≥97.0%), myricetin (≥96.0%), quercetin (≥95.0%), rutin trihydrate (≥95.0%), and resveratrol (≥99.0%) were supplied by Sigma-Aldrich (Madrid, Spain). The analytical standard, hesperidin (≥98.0%) was provided by European Pharmacopoeia. Phenolic stock solutions (200 mg·L⁻¹) were prepared in MeOH, 80:20 (v/v) ethanol-water mixture (for quercetin), or 5% (v/v) DMSO aqueous solution (for hesperidin). These solutions were stored in the dark at 4 °C or −80 °C for up to two months (of myricetin, hesperidin, trans-ferulic, and caffeic acid). Fresh working standard solutions were prepared daily by diluting the stock solutions as required.