104
hand increased sensory acceptance and prevented lipid hydrolysis, on the other
hand increased trimethylamine formation (Garcia‐Soto et al. 2015). Similar good
results were obtained with soft-shell lobster (Homarus americanus) treated with
sodium tripolyphosphate (STP) prior to freezing. Lobsters previously were injected
with STP then cooked in a steam cooker followed by frozen with liquid nitrogen. As
a result, it was determined that STP treatment increases the shelf life of lobsters,
preserves texture colour and flavour properties, and reduces drip loss (Calder
et al. 2005).
In another study, the crayfish (Astacus leptodactylus) caught from the reservoir
lake of Aras dam were immediately transported to the laboratory with ice, washed
with water, their tail peeled, and their tail fillets removed. Fillets placed in polyamide bags were packaged by exposure to air and stored at −18 °C for 6 months in a
freezer. The results showed that freshwater crayfish tail fillets packaged in air can be
stored maximum 5 months at −18 °C (Fard et al. 2015).
Unfavourable conditions may occur in freezing of lobsters in the shell, such as
toughening in meat, off-flavour in storage, and difficulty in separating meat after
thawing. In lobster, blue or black discoloration is one of the most troublesome problems. After freezing or during frozen storage, blueing may occur. This phenomenon
may even occur after it has been thawed and subsequently exposed to air or shortly
after cooking. This bluish black change can be caused by biuret type reactions
between copper pigments and heat denatured protein. Other discoloration problems
found in lobster meats are yellowing and fading of the red or orange-red carotenoid.
Both indicate oxidation during processing or prolonged storage. Air exposure time,
temperature, freezing and storage conditions are effective on this change. Frozen
lobsters gradually lose their juice during freezing and frozen storage. This leads to
textural changes. In addition, protein denaturation during freezing and storage leads
to textural changes (Noomhorm and Vongsawasdi 2004).
Canning of Lobsters
Boiling is the first stage of processing lobsters for canning. Live lobsters are placed
in a basket and then placed in boiling water. Boiling water usually contains 3% salt.
After 10–30 min of boiling, the lobsters are cooled in 2–6% chilled brine. Boiling
time varies according to lobster size. Once the lobsters have cooled sufficiently,
claws and tails are severed. After the body shell is opened, the stomach, liver and
coral are removed, and the body is removed from the shell. The claws are broken,
and the meat is taken as whole as possible. Tails are split and intestines are pulled.
In the canning process, lacquered tin cans are used to package lobsters. Usually, the
arm meat and tails are placed at the bottom of the can, while the claws meat is
placed on top. Then a small amount of salt is added. If the lobsters are to be packaged in cold boxes, the cans must be heated before closing. Heating is carried out by
passing the cans through an exhaust tunnel, thereby achieving a temperature of
60 °C in the centre of the cans. Vacuum sealing of the cans is recommended using a
mechanical vacuum container sealing machine (Anonymous 2016).
2 Crustacean Shellfish
hand increased sensory acceptance and prevented lipid hydrolysis, on the other
hand increased trimethylamine formation (Garcia‐Soto et al. 2015). Similar good
results were obtained with soft-shell lobster (Homarus americanus) treated with
sodium tripolyphosphate (STP) prior to freezing. Lobsters previously were injected
with STP then cooked in a steam cooker followed by frozen with liquid nitrogen. As
a result, it was determined that STP treatment increases the shelf life of lobsters,
preserves texture colour and flavour properties, and reduces drip loss (Calder
et al. 2005).
In another study, the crayfish (Astacus leptodactylus) caught from the reservoir
lake of Aras dam were immediately transported to the laboratory with ice, washed
with water, their tail peeled, and their tail fillets removed. Fillets placed in polyamide bags were packaged by exposure to air and stored at −18 °C for 6 months in a
freezer. The results showed that freshwater crayfish tail fillets packaged in air can be
stored maximum 5 months at −18 °C (Fard et al. 2015).
Unfavourable conditions may occur in freezing of lobsters in the shell, such as
toughening in meat, off-flavour in storage, and difficulty in separating meat after
thawing. In lobster, blue or black discoloration is one of the most troublesome problems. After freezing or during frozen storage, blueing may occur. This phenomenon
may even occur after it has been thawed and subsequently exposed to air or shortly
after cooking. This bluish black change can be caused by biuret type reactions
between copper pigments and heat denatured protein. Other discoloration problems
found in lobster meats are yellowing and fading of the red or orange-red carotenoid.
Both indicate oxidation during processing or prolonged storage. Air exposure time,
temperature, freezing and storage conditions are effective on this change. Frozen
lobsters gradually lose their juice during freezing and frozen storage. This leads to
textural changes. In addition, protein denaturation during freezing and storage leads
to textural changes (Noomhorm and Vongsawasdi 2004).
Canning of Lobsters
Boiling is the first stage of processing lobsters for canning. Live lobsters are placed
in a basket and then placed in boiling water. Boiling water usually contains 3% salt.
After 10–30 min of boiling, the lobsters are cooled in 2–6% chilled brine. Boiling
time varies according to lobster size. Once the lobsters have cooled sufficiently,
claws and tails are severed. After the body shell is opened, the stomach, liver and
coral are removed, and the body is removed from the shell. The claws are broken,
and the meat is taken as whole as possible. Tails are split and intestines are pulled.
In the canning process, lacquered tin cans are used to package lobsters. Usually, the
arm meat and tails are placed at the bottom of the can, while the claws meat is
placed on top. Then a small amount of salt is added. If the lobsters are to be packaged in cold boxes, the cans must be heated before closing. Heating is carried out by
passing the cans through an exhaust tunnel, thereby achieving a temperature of
60 °C in the centre of the cans. Vacuum sealing of the cans is recommended using a
mechanical vacuum container sealing machine (Anonymous 2016).
2 Crustacean Shellfish