Abstract
We measured pepsin-like protease activity, hydrochloric acid (HCl) concentration, and pH in freshly collected gastric juice (GJ) from farmed Pacific bluefin tuna (Thunnus orientalis) to demonstrate the experimental conditions required for in vitro artificial gastric digestion. A positive correlation was confirmed between HCl concentration and pepsin-like protease activity (r =0.847). This suggests that the oxynticopeptic cells in bluefin tuna secrete pepsinogens, together with HCl. Thus, we concluded that the conditions for simulated in vitro gastric digestion are around 17 mg tyrosine liberated/ml GJ/30 min incubation of pepsin-like protease activity and 0.04% HCl.
