38
in tanks in the fish hold. In the previous study, prawn (Metapenaeus dobsoni) was
chilled in two ways, chilling with icing and chilled sea water. In the icing, washed
shrimps were packed with crushed ice. The second group of prawns were kept in a
closed sea water system cooled to 1.7–3.8 °C. The prawn held in chilled sea water
have been found to be superior in general appearance, firmness of the meat and
absence of external damage in shell and flesh as compared with those in ice. On the
other hand, melanosis has been considerably inhibited. Better results with chilled seawater have been obtained in terms of microbiological (Nayar et al. 1962).
Acidic Electrolyzed Water (AEW) Ice
Another alternative cooling method is acidic electrolyzed water (AEW) ice. In a
study investigating the effect of acidic electrolyzed water ice on preserving the quality of shrimp (Litopenaeus vannamei), it has been reported that AEW ice is more
effective in inhibiting the formation of total volatile basic nitrogen (TVBN) and
bacterial growth compared to tap water ice (Lin et al. 2013; Wang et al. 2014). On
the other hand, it has also been reported that acidic electrolyzed water ice can inhibit
the shrinkage in muscle fibres of shrimps (Wang et al. 2015).
Superchilling
Super chilling is a process in which the temperature of a food product is reduced to
1–2 °C below the initial freezing point of the product. The initial freezing point of
the food is between −0.5 and −2.8 °C. Generally, super chilling is positioned
between freezing and refrigeration, where the ambient temperature is set below the
initial freezing point. Super chilling produces ice on the surface, which absorbs the
heat in the interior. This means that there is no need for external icing around the
product in transport or storage for shorter periods of time. For long-term storage of
the super-chilled product, storage at super-chilling temperatures will be necessary.
Microbial growth is the most important factor limiting the shelf life and quality of
foods. Microbial activity decreases at super cooling temperatures and most bacteria
cannot grow (Kaale et al. 2011). Super-chilling (2 °C) and refrigeration (5 °C) were
applied to shrimp (Penaeus japonicus) and their effects on the quality of shrimp
were compared. Better results were obtained with super-chilled samples, compared
to refrigerated ones. Colour, hardness was better maintained, and K value suppressed in case of super-chilling (Ando et al. 2004).
Combination of Chilling with Other Preservation Methods
Chilling was applied together with other preservation methods to increase the quality and the shelf life of shrimps. One of these applications is the cold storage of
shrimps packaged in a modified atmosphere. Lannelongue et al. (1982) reported
2 Crustacean Shellfish
in tanks in the fish hold. In the previous study, prawn (Metapenaeus dobsoni) was
chilled in two ways, chilling with icing and chilled sea water. In the icing, washed
shrimps were packed with crushed ice. The second group of prawns were kept in a
closed sea water system cooled to 1.7–3.8 °C. The prawn held in chilled sea water
have been found to be superior in general appearance, firmness of the meat and
absence of external damage in shell and flesh as compared with those in ice. On the
other hand, melanosis has been considerably inhibited. Better results with chilled seawater have been obtained in terms of microbiological (Nayar et al. 1962).
Acidic Electrolyzed Water (AEW) Ice
Another alternative cooling method is acidic electrolyzed water (AEW) ice. In a
study investigating the effect of acidic electrolyzed water ice on preserving the quality of shrimp (Litopenaeus vannamei), it has been reported that AEW ice is more
effective in inhibiting the formation of total volatile basic nitrogen (TVBN) and
bacterial growth compared to tap water ice (Lin et al. 2013; Wang et al. 2014). On
the other hand, it has also been reported that acidic electrolyzed water ice can inhibit
the shrinkage in muscle fibres of shrimps (Wang et al. 2015).
Superchilling
Super chilling is a process in which the temperature of a food product is reduced to
1–2 °C below the initial freezing point of the product. The initial freezing point of
the food is between −0.5 and −2.8 °C. Generally, super chilling is positioned
between freezing and refrigeration, where the ambient temperature is set below the
initial freezing point. Super chilling produces ice on the surface, which absorbs the
heat in the interior. This means that there is no need for external icing around the
product in transport or storage for shorter periods of time. For long-term storage of
the super-chilled product, storage at super-chilling temperatures will be necessary.
Microbial growth is the most important factor limiting the shelf life and quality of
foods. Microbial activity decreases at super cooling temperatures and most bacteria
cannot grow (Kaale et al. 2011). Super-chilling (2 °C) and refrigeration (5 °C) were
applied to shrimp (Penaeus japonicus) and their effects on the quality of shrimp
were compared. Better results were obtained with super-chilled samples, compared
to refrigerated ones. Colour, hardness was better maintained, and K value suppressed in case of super-chilling (Ando et al. 2004).
Combination of Chilling with Other Preservation Methods
Chilling was applied together with other preservation methods to increase the quality and the shelf life of shrimps. One of these applications is the cold storage of
shrimps packaged in a modified atmosphere. Lannelongue et al. (1982) reported
2 Crustacean Shellfish