Immunologially Applicability for Foods of Short Chain Peptides Derived from Sardines

Short chain peptides with the average chain length of 2.67 prepared from sardine protein have reductive effects on blood pressure, and are expected to be a physiologically functional foodstuff. The short chain peptides were found to be negative in the active systemic anaphylaxis (ASA) test in guinea pigs sensitized by oral administrations of the short chain peptides. Negative results were also obtained in the homologous passive cutaneous anaphylaxis (PCA) test, which was done against sera from guinea pigs sensitized by oral administration of the short chain peptides. The short chain peptides have a potent angiotensin I converting enzyme (ACE) inhibitory activity, this enzyme catalyses the activation of angijotensin II and inactivation of bradykinin. The bradykinin is able to stimulate macrophages, to enhance lymphocyte migration, and to increase secretion of lymphokines. The short chain peptides favor bradykinin activity, which showed concentrated pigment coloration in the PCA test by subcutaneous sensitization. These results suggest that the short chain peptides have no antigenicity by oral administration, and are usable in foods.