Abstract: Proteins from silver carp muscle were extracted by the pH-shift method and used for a comparative investigation into heat-induced gel properties between them and water-washed surimi. Myosin heavy chain was more dramatically degraded, and actin decreased in proteins extracted under acidic conditions when compared to water-washed surimi. The highest actin level was found in proteins resulting from alkali extraction. Heat-induced gelation caused partial degradation of myosin heavy chain in proteins extracted under alkali conditions. The gelation temperature and storage modulus G＇ of pH-shift isolated proteins were lower than those of water-washed surimi. Weight loss was considerably higher in heat-induced gels of proteins extracted under acidic conditions in comparison with water-washed surimi and those extracted under alkali conditions, between which no significant difference existed (P＜0.05). Both proteins indicated a significant decrease in water-holding capacity when compared with water-washed surimi (P＜0.05). Proteins extracted under alkali conditions had the lowest gel strength (46.81 N × mm), but no significant difference between proteins resulting from alkali extraction and water-washed surimi (P＜0.05). Based on these results, we draw the conclusion that alkali extraction is a more suitable method for protein extraction from silver carp muscle.

Key words: silver carp, surimi, pH-shift method, gel properties