For the enzymatic digestion, α-Amylase from Bacillus sp. (A4862-250ML, liquid form), Lipase from Aspergillus niger (62301, powder), Papain from Carica papaya (10108014001 Roche, Basel, Switzerland, stock concentration 100 mg/10 mL, suspension form) and sodium dodecyl sulphate (SDS, liquid form) were supplied by Sigma-Aldrich (Darmstadt, Germany) such as sucrose and zinc chloride (ZnCl2) used for the gradient density separation.
For the filtration step, the membrane filters were made by Whatman®, Sigma-Aldrich (Darmstadt, Germany) (filters of cellulose nitrate 12 μm and aluminum oxide (Anodisc) 0.1 μm were used).