Chemistry Reference
In-Depth Information
MTGase has been used widely in restructured fish products to reduce the salt required
due to its ability in protein cross-linking. Usually a decrease in salt level to below 2% has
a negative effect on the functional and mechanical properties of meat product. Sufficient
amount of salt is required for protein solubilization. Salt at 1.5% is considered to be the
minimum level needed for gel development.
115
Tellez-Luis
et al
.
116
found that low salt
restructured silver carp products with improved mechanical and functional properties can
be successfully prepared using MTGase (3 g kg
−
1
) and 1% NaCl. Additionally, MTGase at
3gkg
−
1
could be used to improve the mechanical properties of restructured product from a
mixture of striped mullet and Mexican flounder (1:1) at both levels of salt (1% and 2%).
117
MTGase has been proven as a potential gel-enhancing agent, which improves gel strength
of surimi produced from low quality lizardfish. Low quality is usually the result of long iced
storage time. During handling and storage, fish muscle proteins undergo both denaturation
and degradation, leading to poor gel formation.
118
Some fish species with formaldehyde form-
ing ability such as lizardfish are susceptible to protein denaturation. As a consequence, gel
formation is generally decreased with increasing storage or handling time. Benjakul
et al
.
119
found that MTGase was a powerful gel enhancer of mince from lizardfish stored in ice for
different times. However, the gel enhancing ability was greater in surimi produced from fresh
lizardfish (see Fig. 10.7).
Fig. 10.7
Breaking force and deformation of mince gel from lizardfish stored in ice for different times
without and with MTGase addition (0.6 U g
−1
sample) and set under different conditions. Different letters
within the same treatment or different capital letters within the same storage time indicate significant
differences (P
<
0.05). Bars represent standard deviation from five determinations. (Reprinted from Ref.
[119].)
