Sodium acetate trihydrate

Methanol and water used was of HPLC (High-Performance Liquid Chromatography) gradient grade and was purchased from Chem-Lab NV (Zedelgem, Belgium). There were used single element standard solutions 1000 mg/L, of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, K, Na, Ca and Mg (Sigma Chem, St. Louis, MO, USA). For trace metal analysis, all glassware and plastic containers used were washed properly, first with nitric acid and then with ultra-pure water, in order to ensure that any contamination does not occur. All the other chemicals and reagents were of analytical grade.
The DPPH (2,2-diphenyl-1-picrylhydrazyl) and (+)-catechin were from Sigma Aldrich, St. Louis, MO, USA, whereas TPTZ (2,4,6-tripyridyl-s-triazine) and aluminum chloride-6-hydrate were obtained from Alfa Aesar, GmbH&GoKG, Karlsruhe, Germany. ABTS (2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), Trolox ((S)-(-)-6-hydroxy-2,5,7,8- tetramethylchroman-2-carboxylic acid), and gallic acid were from J&K Scientific GmbH, Pforzheim, Germany. Folin-Ciocalteu reagent, sodium acetate trihydrate and sodium hydroxide (HPLC grade) were obtained from Chem-Lab NV, Zedelgem, Belgium. Iron (III) chloride hexahydrate, sodium carbonate, and sodium nitrite was from Merck, KGaA, Darmstadt, Germany. All the other chemicals used were of analytical grade.

Pectinase from Aspergillus aculeatus (Pectinex® Ultra Clear, a blend of pectinases, hemicellulases and arabinases with activity of 8600 PGNU/g) and (Pectinex® Ultra SP-L, a blend of pectinases, hemicellulases and beta-glucanases with activity of 3300 PGNU/g), cellulase from Trichoderma reesei (Celluclast® 1.5L, a cellulase aqueous solution with activity of ≥700 units/g) were obtained from Sigma Aldrich (Darmstadt, Germany). Information about the optimal conditions of these enzymes as declared by the producer can be found in Table 1. Microcrystalline cellulose Avicel® PH-101, pectin from citrus peel, 3,5-dinitro salicylic acid, D-(+)-galacturonic acid monohydrate and D-(+)-glucose were purchased from Sigma Aldrich (Darmstadt, Germany). Sodium carbonate anhydrous, citric acid, sodium hydroxide, and L (+)-potassium sodium tartrate tetrahydrate were purchased from VWR Chemicals (Leuven, Belgium), while di-sodium hydrogen phosphate anhydrous, sodium acetate trihydrate, and acetic acid 99–100 % were obtained from Chem-Lab (Zedelgem, Belgium).Table 1

Conditions range of activity of the used enzymes as declared by the producer.

Enzyme	pH range of activity	Temperature range of activity
Pectinex® Ultra Clear	1.8–3.0	25–40 °C
Pectinex® Ultra SP-L	2.8–6.5	15–55 °C
Celluclast® 1.5L	4.0–6.0	50–60 °C