32
et al. 2004). Progression of lipid oxidation leads to undesirable odour and taste formation. Frozen prawn (Macrobrachium rosenbergii) was sensorial acceptable during storage for 8 weeks at −20 °C. Odour and flavour was in excellent up to 4th
weeks. After 12th week, there were losses in bright appearance, natural odour, and
flavour (Siddiqui et al. 2011). However, Rahman et al. (2000) determined that two
shrimp species, giant freshwater prawn (Macrobrachium rosenbergii) and marine
tiger shrimp (Panaeus monodon), were in acceptable condition for colour, odour,
appearance, and texture until the 5th day of ice storage.
2.1.3 Shrimp/Prawn Processing and Preservation
2.1.3.1 Alive Transportation of Shrimps
With the increasing purchasing power, consumers started to be more selective about
quality when buying shrimps. Most consumers want to provide shrimps alive. Live
shrimps show a better quality and flavour. Live shipping has become one of the
major applications in the shrimp industry to increase the value and to keep the freshness of the final product. Since the autolysis begins rapidly after the death of
shrimps, the quality of the food made with shrimp depends on the freshness.
If shrimps are to be marketed live, special care must be taken to reduce stress and
minimize harvest damage as far as possible to ensure long-term post-harvest survival. There are several ways to keep shrimps alive. These; still water, balance system, closed circulation system, open circulation system, plastic bags with or without
oxygen and use of iced/iceless sawdust. Size and species of shrimp and length of
travel are important factors to consider before choosing the ideal transportation
method. The most recommended of these methods is the use of sawdust. For this
purpose, chilled sawdust is used. This method is easy and inexpensive (Iranto and
Giyatmi 1997).
Temperature and dissolved oxygen are the two main parameters which must be
checked constantly and improved prior and during transportation. The basic principle of live transport of shrimps is to reduce the temperature to slow down metabolic activity. The water temperature is reduced to a limit where the animal’s
metabolic rate is minimized, so that storage and transport in this case does not cause
an increase in metabolic rate. This creates an anaesthetic effect on shrimp. Cold
anesthetized shrimp movements are minimal, no stress occurs, weight loss is virtually absent and does not produce faeces as there is no food intake (Schoemaker
1991). After the shrimps are moved to their destination, the temperature is brought
to ambient temperature and the anaesthesia effect removes. Generally, temperatures
below 14 °C and above 35 °C are fatal for shrimps. Some species can tolerate
12 °C. Richards-Rajadurai (1989) reported that P. monodon could not tolerate
12–14 °C but was suitable for M. japonicus. During experimental live storage under
cold anaesthesia, it was found that farmed P. monodon lived better at 16 °C than at
2 Crustacean Shellfish
et al. 2004). Progression of lipid oxidation leads to undesirable odour and taste formation. Frozen prawn (Macrobrachium rosenbergii) was sensorial acceptable during storage for 8 weeks at −20 °C. Odour and flavour was in excellent up to 4th
weeks. After 12th week, there were losses in bright appearance, natural odour, and
flavour (Siddiqui et al. 2011). However, Rahman et al. (2000) determined that two
shrimp species, giant freshwater prawn (Macrobrachium rosenbergii) and marine
tiger shrimp (Panaeus monodon), were in acceptable condition for colour, odour,
appearance, and texture until the 5th day of ice storage.
2.1.3 Shrimp/Prawn Processing and Preservation
2.1.3.1 Alive Transportation of Shrimps
With the increasing purchasing power, consumers started to be more selective about
quality when buying shrimps. Most consumers want to provide shrimps alive. Live
shrimps show a better quality and flavour. Live shipping has become one of the
major applications in the shrimp industry to increase the value and to keep the freshness of the final product. Since the autolysis begins rapidly after the death of
shrimps, the quality of the food made with shrimp depends on the freshness.
If shrimps are to be marketed live, special care must be taken to reduce stress and
minimize harvest damage as far as possible to ensure long-term post-harvest survival. There are several ways to keep shrimps alive. These; still water, balance system, closed circulation system, open circulation system, plastic bags with or without
oxygen and use of iced/iceless sawdust. Size and species of shrimp and length of
travel are important factors to consider before choosing the ideal transportation
method. The most recommended of these methods is the use of sawdust. For this
purpose, chilled sawdust is used. This method is easy and inexpensive (Iranto and
Giyatmi 1997).
Temperature and dissolved oxygen are the two main parameters which must be
checked constantly and improved prior and during transportation. The basic principle of live transport of shrimps is to reduce the temperature to slow down metabolic activity. The water temperature is reduced to a limit where the animal’s
metabolic rate is minimized, so that storage and transport in this case does not cause
an increase in metabolic rate. This creates an anaesthetic effect on shrimp. Cold
anesthetized shrimp movements are minimal, no stress occurs, weight loss is virtually absent and does not produce faeces as there is no food intake (Schoemaker
1991). After the shrimps are moved to their destination, the temperature is brought
to ambient temperature and the anaesthesia effect removes. Generally, temperatures
below 14 °C and above 35 °C are fatal for shrimps. Some species can tolerate
12 °C. Richards-Rajadurai (1989) reported that P. monodon could not tolerate
12–14 °C but was suitable for M. japonicus. During experimental live storage under
cold anaesthesia, it was found that farmed P. monodon lived better at 16 °C than at
2 Crustacean Shellfish