Sodium nitrate

Methylene blue (> 99%, MW 319.89 Da) was purchased from Aqua-Med® (Łódź, Poland). Thiamine hydrochloride (99%, MW 337.27 Da), biotin (> 99%, MW 244.31 Da), vitamin B12 (> 98%, MW 1355.37 Da) were supplied by Sigma-Aldrich (St. Louis, MO, USA). Hydrogen peroxide (30%, MW 34.01 Da), sodium nitrate (> 99%, MW 84.99 Da), sodium dihydrogen phosphate monohydrate (> 99%, MW 137.99 Da), sodium molybdate dihydrate (> 99%, MW 241.95 Da), manganese (II) chloride tetrahydrate (> 99%, MW 197.91 Da), and cobalt (II) chloride hexahydrate (> 99%, DW 237.93 Da) were obtained from Chempur® (Piekary Śląskie, Poland). Zinc sulfate heptahydrate (> 99%, MW 287.54 Da), iron (III) chloride hexahydrate (> 99%, MW 270.32 Da), EDTA disodium dihydrate (> 99%, MW 372.24 Da), and copper (II) sulfate pentahydrate (> 99%, MW 249.68 Da) were purchased from Scharlab (Barcelona, Spain). Nonahydrate sodium metasilicate (44–47.5% total solids, MW 284.19 Da) was supplied by Acros Organics, ThermoFisher Scientific (Waltham, MA, USA). Sodium hydroxide, hydrohloric acid and standard buffered solutions pH 2.0, 7.0 and 10.0 were purchased from Sigma-Aldrich. Deionized water was obtained by using a Milli-Q® purification system (Millipore Co., Bedford, MA, USA).

Thiamine hydrochloride (99%, MW 337.27), biotin (>99%, MW 244.31), vitamin B12 (>98%, MW 1355.37), and α-Cyano-4-hydroxycinnamic acid (>99%, MW 189.17), 4-Nitrophenol (>99%, MW 139.11) were supplied by Sigma-Aldrich (St. Louis, MO, USA). Hydrogen peroxide (30%, MW 34.01), sodium nitrate (>99%, MW 84.99), sodium dihydrogen phosphate monohydrate (>99%, MW 137.99), sodium molybdate dihydrate (>99%, MW 241.95), manganese (II) chloride tetrahydrate (>99%, MW 197.91), and cobalt (II) chloride hexahydrate (>99%, DW 237.93) were obtained from Chempur^® (Piekary Śląskie, Poland). Zinc sulfate heptahydrate (>99%, MW 287.54), iron (III) chloride hexahydrate (>99%, MW 270.32), EDTA disodium dihydrate (>99%, MW 372.24), and copper (II) sulfate pentahydrate (>99%, MW 249.68) were purchased from Scharlab (Barcelona, Spain). Sodium metasilicate nonahydrate (44–47.5% total solids, MW 284.19) were supplied by Acros Organics, ThermoFisher Scientific (Waltham, MA, USA). Deionized water was obtained by using a Milli-Q^® purification system (Millipore Co., Bedford, MA, USA). Standards of D-glucose (>99%), D-alanine (>99%) and cesium triiodide (>99%) were purchased from Sigma-Aldrich (Steinheim, Germany). Standard mixture of triacylglycerols (TG internal standard, Ultimate SPLASH^TM) was purchased from Avanti Polar Lipids (Alabaster, AL, USA).

2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH), 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), methanol, water and galic acid was purchased from Sigma-Aldrich (St. Louis, MO, USA). Folin–Ciocalteu’s phenol reagent, sodium carbonate (Na₂CO₃) and sodium nitrate were purchased from Chempur (Piekary Slaskie, Poland). Ultrapure water (resistivity 18.2 MΩ cm), obtained from a Milli-Q purification system (Millipore, Bedford, MA, USA), was used for all analyses. Teff flour, sorghum groats, lecithin, olives and beeswax were purchased at local stores.