Abstract:

The effect of inoculation with Bacillus licheniformis on gel properties of grass carp myofibrillar protein during
subsequent storage at different temperatures was investigated. The results showed that gel properties were greatly affected
by Bacillus licheniformis, resulting in severely damaged gel structure. At 4 and 25 ℃，with the extension of storage time,
gel strength, hardness, elasticity and whiteness showed a falling trend, and the control group presented a more significant
decrease than the blank group. The total number of colonies in the two groups increased significantly, and the free water
content of myofibrillar protein gels increased gradually with storage period, especially significantly in the control group,
which in turn showed poorer water retention capacities. Moreover, the microstructure of gels was damaged and became more
loose and porous, which was initially dense, as observed by FE-SEM. In addition, sodium dodecyl sulfate-polyacrylamide
gel electrophoresis (SDS-PAGE) results showed that myosin heavy chain (MHC) and actin were gradually degraded. The
control group displayed a higher degree of structure and protein degradation than the blank group. Bacillus licheniformis
grew better at 25 ℃, leading to more serious damage to the gel than at 4 ℃.

Key words: Bacillus licheniformis, grass carp, myofibrillar protein, gel properties