Effects of pepsin digestion at different temperatures and times on properties of telopeptide-poor collagen from bird feet

This study was conducted to evaluate the effect of pepsin digestion at different temperatures (4, 12, 18 and 24 degrees C) and times (24, 36, 48 and 72 h) on properties of telopeptide-poor collagen from bird feet (TPCBF). The yield, SDS-PAGE, in vitro fibrillogenesis and denaturation temperature of the TPCBF from different treatments were determined. The results showed that the TPCBF yield increased as temperature and time increased. The yield of lots treated at 4 degrees C were significantly lower than those of the treatments at 12, 18 and 24 degrees C. In the SDS-PAGE electrophoretogram, the low molecular fragments of samples treated at 12, 18 and 24 degrees C were higher than those at 4 degrees C. The fibrillogenesis rate of lots at different temperatures decreased as treated time increased. The denaturation temperatures of the samples treated at 24 degrees C for 48 and 72 h were significantly lower than those of the treatments at 4, 12 and 18 degrees C, for all times. These changes could be related to telopeptide removal and lost molecular integrity of collagen by pepsin digestion at a high temperature and long time of treatment. However, the optimum conditions of pepsin treatment should be controlled at 12 degrees C for 24 h due to the best fibril-forming capacity, high denaturation temperature and an acceptable yield shown in this study. (c) 2005 Elsevier Ltd. All rights reserved.