Potassium chloride (kcl)

All chemicals and reagents used in the experiments were of per analysis and HPLC grade. Folin–Ciocalteu reagent, potassium chloride, sodium hydrogencarbonate, potassium hydrogenphosphate, magnesium chloride hexahydrate, sodium chloride, ammonium carbonate, sodium hydroxide, and petroleter were supplied from Kemika d.d. (Zagreb, Croatia). Anhydrous sodium carbonate and sodium nitrite were acquired from Gram-Mol d.o.o. (Zagreb, Croatia). Sodium molybdate (>98%) was supplied from abcr Gmbh (Karlsruhe, Germany). Methanol, acetonitrile, concentrated hydrochloric acid (37%, v/v), sodium hydroxide, and formic acid were purchased from Carlo Erba Reagents (Val de Reuil, France). Secondary analytical standards, i.e., echinacoside (>98%) and verbascoside (>98%), were obtained from Biosynth s.r.o. (Bratislava, Slovakia), whereas caffeine was supplied from Fluka (Taufkirschen, Germany). Theobromine (min. 99%), human salivary α–amylase XII-A (Enzyme Commission number: 3.2.1.1.; 1149 U mg⁻¹ protein), pepsin from porcine gastric mucosa (474 U mg⁻¹ protein), pancreatin from porcine pancreas (4×USP), and bile bovine salts (unfractionated) were provided from Sigma Aldrich (St. Louis, MO, USA).

Tart cherries were purchased at a local market, pits were removed, and flesh was used for the preparation of jams. The following chemicals were used: Potassium chloride, sodium acetate, hydrochloric acid, methanol, sodium carbonate, sodium bisulfite, Folin-Ciocalteu reagent were purchased from Kemika (Zagreb, Croatia). Trolox, 2,2’-azinobis (3-ethylbenzothiazoline sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazil (DPPH) were purchased from Sigma-Aldrich (St. Louis, MO, USA).

In this study, the following reagents and standards were used: aluminium chloride, quercetin dihydrate, gallic acid monohydrate, potassium persulfate, Trolox, 2,2-azinobis(3-ethylbenzothiazoline sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazil (DPPH), 2,4,6-tripyridyl-s-triazine (TPTZ) were obtained from Sigma-Aldrich (St. Lois, MO, USA); HPLC standards (gallic and caffeic acid, (+)-catechin hydrate, (−)-epicatechin, rutin hydrate, quercetin) were purchased from Sigma-Aldrich Chemie Gmbh (Steinheim, Germany), and malvidin 3-glucoside from Extrasynthese (Genay, France). Folin–Ciocalteu reagent, sodium nitrite, sodium carbonate, sodium hydroxide, potassium bisulphite, sodium acetate, potassium chloride and hydrochloric acid were purchased from Kemika (Zagreb, Croatia); sodium acetate trihydrate, ferric chloride hexahydrate, and ammonium acetate were purchased from Gram-Mol (Zagreb, Croatia); copper(II) chloride from Acros Organics (New Jersey, NJ, USA); HPLC grade methanol and neocuproine from Merck (Darmstadt, Germany) and phosphoric acid (HPLC grade) were obtained from Fluka (Buchs, Switzerland).