EFFECTS OF ACID AND ALKALI TREATMENT ON THE PROPERTIES OF PROTEINS RECOVERED FROM WHOLE GUTTED GRASS CARP (CTENOPHARYNGODON IDELLUS) USING ISOELECTRIC SOLUBILIZATION/PRECIPITATION

摘要

The objective of this study was to investigate the properties of proteins from whole gutted grass carp using isoelectric solubilization/precipitation. The solubility of grass carp muscle protein was the lowest at pH 5 and the highest either at pH 3 or 12. The acid and alkali treatments could significantly increase the protein yield and decrease the fat content, while the alkali treatment led to higher protein yield than the acid treatment. The gels from protein isolates from alkali treatment or surimi from conventional water washing had higher breaking force and deformation than those of acidic treatment. The storage modulus (G') indicated that the grass carp muscle proteins underwent denaturation during acid and alkali treatments. Protein isolates from both alkali and acid treatments showed the similar rheological patterns. This study showed that the acid or alkali treatments may be used to produce surimi from grass carp using isoelectric solubilizaion/ precipitation.