“…A combination of trypsin-chymotrypsin (Rizzello et al, 2008), pepsin-pancreatin (Robert et al, 2004), pepsin-corolase PP (Quiros et al, 2005), pepsin-trypsin (Koo et al, 2006) or pepsin-trypsin-protease N (Hyoung et al, 2004) enzymes have been employed for this purpose. This procedure has been assayed with peptides isolated from sea cucumber (Zhao et al, 2009), rice (Kuba et al, 2009), oyster (Wang et al, 2008a), porcine hemoglobin , and wakame (Sato et al, 2002) hydrolysates. Resistance to intestinal digestion can also be demonstrated by the use of a model system such as Caco-2 cells.…”