Comparison of physicochemical and functional properties of duck feet and bovine gelatins

BACKGROUND Previous studies have indicated that duck feet are a rich source of gelatin extractable from avian sources. In this study, the physicochemical and functional properties of avian gelatin extracted from duck feet ( DFG ) with acetic acid were compared with those of commercial bovine gelatin ( BG ). RESULTS The yield of DFG obtained in this study was 7.01 ± 0.31%. High‐performance liquid chromatography analysis indicated that the imino acid content was slightly lower for DFG compared with BG ( P < 0.05). Differences in molecular size and amino acids between DFG and BG were also observed. The isoelectric points of DFG and BG were at pH 8 and 5 respectively, and the overall protein solubility of BG was higher than that of DFG . Gels prepared from BG exhibited higher bloom strength, viscosity and clarity and were darker in colour compared with DFG gels ( P < 0.05). The gelling and melting points of BG were 21.8 and 29.47 °C respectively, while those of DFG were 20.5 and 27.8 °C respectively. BG exhibited slightly better emulsifying and foaming properties compared with DFG . CONCLUSION Although some differences between DFG and BG were observed, the disparities were small, which indicates that DFG could be exploited commercially as an alternative source of gelatin. © 2016 Society of Chemical Industry