EFFECTS OF HEAT TREATMENT AND PEPSIN DIGESTION ON TRYPSIN INHIBITORY ACTIVITY AND OVOMUCOID ANTIGENICITY OF JAPANESE QUAIL EGG WHITE

Changes in trypsin inhibitory activity and ovomucoid antigenicity in the egg white of Japanese quail egg were observed after subjecting the quail egg to boiling, saúteing and microwave irradiation. Boiling for 10 min caused about 50% loss of the initial trypsin inhibitory activity. With respect to antigenicity, the boiling caused an initial increase followed by a drop to the original level. Saúteing for 3 min resulted in about 90% loss of the inhibitory activity and about 75% loss of the initial antigenicity. Microwave irradiation for 90 s resulted in about 85% loss of the inhibitory activity and about 80% loss of the initial antigenicity. After pepsin digestion of the egg white boiled for 10 min, 100% of the starting trypsin inhibitory activity was retained even after 24 h digestion, while the antigenicity decreased to about 10% of the initial activity. These results suggest that about 50% of the original trypsin inhibitory and 10% of the original antigenic activity remain after a 24 h pepsin digestion of the egg white boiled for 10 min. Thus, we concluded that intact ovomucoid or ovomucoid degradation products with some trypsin inhibitory activity and antigenicity were introduced into the small intestine after ingestion of the cooked egg white of Japanese quail.