Influence of different processing methods on anti-trypsin activity in bovine colostrum

Abstract

Trypsin-inhibitory activity represents a general characteristic of the first bovine colostrum. The objectives of this study were to establish a test to determine anti-trypsin activity and test the hypothesis that freezing, acidification, and heat treatment would alter anti-trypsin activity compared with untreated bovine colostrum. A photometric assay was established to determine anti-trypsin activity. The activity was expressed in milligrams of inhibited trypsin per milliliter of colostrum. In experiment 1, anti-trypsin activity was compared in untreated and frozen colostrum of the same sample. In 40 untreated colostrum samples, the trypsin-inhibition (0.80 mg/mL) corresponded to that observed in frozen samples (0.79 mg/mL). In experiment 2, we compared the antitrypsin activity of 99 samples of frozen colostrum (0.85 mg/mL) with aliquots subjected to acidification (0.84 mg/mL), heat treatment at 60°C for 60 min (0.65 mg/mL), and heat treatment at 63.5°C for 30 min (0.61 mg/mL). Acidification did not significantly affect trypsin inhibition. Both heat treatment protocols significantly reduced anti-trypsin activity.