myosin;
secondary structure;
gel property;
microstructure;
pH;
D O I:
10.1016/j.meatsci.2008.02.014
中图分类号:
TS2 [食品工业];
学科分类号:
0832 ;
摘要:
Secondary structures, gelation properties and their relationships in porcine myosin were studied by circular dichroism, dynamic rheological measurement and scanning electron microscopy. Gelling of porcine myosin involved a change in myosin conformation with protein-protein and protein-water interactions. The gelation properties were strongly pH and temperature dependent. Near the pI (pH 5.5 and 6.0), porcine myosin could spontaneously coagulate at 15 degrees C resulting partially from the presence of more beta-sheets. Myosin at pH 6.5-9.0 began to form a gel at temperatures greater than 38 degrees C. Heating caused alpha-helices to partially turn into beta-sheets and random coils. Subsequently, myosin aggregated and formed a gel network. The gel strength decreased and the water-holding capacity (WHC) increased with increasing pH. Correlation analysis indicated that both the unfolding of alpha-helices and the formation of beta-sheets favored the gelation of porcine myosin. A high beta-sheet fraction prior to heating resulted in a low WHC of resultant gel. A compact and uniform gel was also obtained at pH 6.5. (C) 2008 Elsevier Ltd. All rights reserved.