226
Tenderization has been achieved for some cephalopod species (Loligo vulgaris,
Octopus vulgaris, Sepia officinalis) frozen at −45 °C and stored at −18 °C for
30 days (Gokoglu et al. 2018). The decreases in hardness and chewiness values
measured by the tissue analyser device were determined after freezing, and the sensory texture scores supported these results. On the other hand, there are researchers
who report otherwise. These researchers reported that the water holding capacity
decreased with the freezing and as a result, a harder and drier structure appeared
(Stanley and Hultin 1982; Mackie 1993; Ueng and Chow 1998). It was thought that
this hardening after freezing may have caused partial dehydration, inorganic salts,
and the oxidation of lipids and the production of formaldehyde.
Heating is another method used to tender cephalopods. Heat treatment is applied
by various cooking methods such as boiling, frying, baking, sous-vide cooking. It is
reported that cephalopod muscles soften after cooking (Otwell and Haman 1979;
Stanley and Hultin 1982; Kolodziejska et al. 1987; Kugino and Kugino 1995; Ando
1996, 1997). Hardness connective tissue protein is associated with collagen. During
the cooking process, the heat turns collagen into gelatin, which provides the muscle
to soften. It is shown as the main cause of softening as the destruction of muscle
cells during heat treatment (Kugino and Kugino 1995). In a study, a significant softening was found in the mantle muscle after 30% gelatinization of collagen by cooking in five squid species (Ando 1996).
As in fish and land animals, the meats of the cephalopods can also be tenderized
with certain enzymes. Enzymes such as papain, bromelain and ficin from plants
have been used as meat tenderizers (Ha et al. 2012; Ketnawa and Rawdkuen 2011;
Koak et al. 2011; Navaeena et al. 2004). Plant proteases are superior to bacterial
enzymes because there are safety problems, such as pathogenicity, to bacterial
enzymes. These enzymes break down muscle proteins when mixed with meat.
These enzymes also hydrolyze collagen and elastin proteins. Decreased hardness
and shear force values of some cephalopod species (L. vulgaris, O. vulgarsi, S. officinalis) treated with papain and bromelain were detected. It has been determined
that enzyme applications cause a decrease in gumminess and chewiness values
besides hardness (Gokoglu et al. 2017b). Seven different enzymes (Alcalase,
Neutrase, Flavourzyme, Protamex, Collupulin, Alphalase, and Bromelain) have
been injected to squid (Dosidicus gigas) body. Six other enzymes, except flavourzyme, were found to be effective in softening jumbo squid. In addition to the
enzyme type, it has been determined that enzyme concentration is also effective,
and high concentrations cause tissue destruction and result in the loss of the shape
of the squid. Therefore, enzyme concentrations should be optimized (Eom
et al. 2015).
Cephalopod muscles can be softened by mechanical means. The traditional way
to overcome the toughness of octopus has been the repeated “beating” of the freshly
caught octopus on the rocks of the sea. This procedure has been adopted by the
industry, and the mechanical beating of the octopus has been carried out in special
tumbling equipment where the octopus is tumbled in water (Gokoglu et al. 2017a).
The tumbling process is reported to have a positive effect on softening (Krause et al.
1978a, b; Lachowicz et al. 2003). Another positive effect of tumbling is that it
3 Molluscan Shellfish
Tenderization has been achieved for some cephalopod species (Loligo vulgaris,
Octopus vulgaris, Sepia officinalis) frozen at −45 °C and stored at −18 °C for
30 days (Gokoglu et al. 2018). The decreases in hardness and chewiness values
measured by the tissue analyser device were determined after freezing, and the sensory texture scores supported these results. On the other hand, there are researchers
who report otherwise. These researchers reported that the water holding capacity
decreased with the freezing and as a result, a harder and drier structure appeared
(Stanley and Hultin 1982; Mackie 1993; Ueng and Chow 1998). It was thought that
this hardening after freezing may have caused partial dehydration, inorganic salts,
and the oxidation of lipids and the production of formaldehyde.
Heating is another method used to tender cephalopods. Heat treatment is applied
by various cooking methods such as boiling, frying, baking, sous-vide cooking. It is
reported that cephalopod muscles soften after cooking (Otwell and Haman 1979;
Stanley and Hultin 1982; Kolodziejska et al. 1987; Kugino and Kugino 1995; Ando
1996, 1997). Hardness connective tissue protein is associated with collagen. During
the cooking process, the heat turns collagen into gelatin, which provides the muscle
to soften. It is shown as the main cause of softening as the destruction of muscle
cells during heat treatment (Kugino and Kugino 1995). In a study, a significant softening was found in the mantle muscle after 30% gelatinization of collagen by cooking in five squid species (Ando 1996).
As in fish and land animals, the meats of the cephalopods can also be tenderized
with certain enzymes. Enzymes such as papain, bromelain and ficin from plants
have been used as meat tenderizers (Ha et al. 2012; Ketnawa and Rawdkuen 2011;
Koak et al. 2011; Navaeena et al. 2004). Plant proteases are superior to bacterial
enzymes because there are safety problems, such as pathogenicity, to bacterial
enzymes. These enzymes break down muscle proteins when mixed with meat.
These enzymes also hydrolyze collagen and elastin proteins. Decreased hardness
and shear force values of some cephalopod species (L. vulgaris, O. vulgarsi, S. officinalis) treated with papain and bromelain were detected. It has been determined
that enzyme applications cause a decrease in gumminess and chewiness values
besides hardness (Gokoglu et al. 2017b). Seven different enzymes (Alcalase,
Neutrase, Flavourzyme, Protamex, Collupulin, Alphalase, and Bromelain) have
been injected to squid (Dosidicus gigas) body. Six other enzymes, except flavourzyme, were found to be effective in softening jumbo squid. In addition to the
enzyme type, it has been determined that enzyme concentration is also effective,
and high concentrations cause tissue destruction and result in the loss of the shape
of the squid. Therefore, enzyme concentrations should be optimized (Eom
et al. 2015).
Cephalopod muscles can be softened by mechanical means. The traditional way
to overcome the toughness of octopus has been the repeated “beating” of the freshly
caught octopus on the rocks of the sea. This procedure has been adopted by the
industry, and the mechanical beating of the octopus has been carried out in special
tumbling equipment where the octopus is tumbled in water (Gokoglu et al. 2017a).
The tumbling process is reported to have a positive effect on softening (Krause et al.
1978a, b; Lachowicz et al. 2003). Another positive effect of tumbling is that it
3 Molluscan Shellfish