61
ture and time sufficient to cause coagulation of fish proteins. Hot smoking is usually
sufficient to kill parasites, destroy non-spored bacterial pathogens, and eliminate the
spores related to human health (FAO 2013). Hot smoking is the process of smoking
the fish at 70–80 °C and thus cooking the fish. In order to stabilize the smoked product at room temperature, it is reported that the water activity (aw) of the hot smoked
fish products should be less than 0.85 (Arason et al. 2014) Cold method is smoking
of salted fish without exceeding the temperature of 33 °C by avoiding of cooking of
meat and coagulation of proteins. The applied temperature is usually 12–15 °C
(Gokoglu 2002). Cold smoking takes longer than hot smoking but provides higher
efficiency and better protects the original textural properties than hot smoked products (Arason et al. 2014).
Almost any type of hard wood can be used for smoke production. The use of
resinous wood is not suitable as it causes a bitter taste in the product. The choice of
wood depends on the desired odour and taste in the final product. The most preferred wood type is oak. Oak, ash, beech, alder, acacia, poplar, apple, willow,
orange, and lemon trees are stated to be the most suitable trees for smoking.
Coniferous trees are not suitable for smoking. Coniferous trees cause the unpleasant
terpentine taste and odour (Gokoglu 2002).
Liquid smoke solutions, which have been produced with the distillation of the
wood and then concentrated to a certain extent, have been used for many years to
give aroma to the meat and fish (Hattula et al. 2001; Arason et al. 2014). Concentrated
smoke is dissolved in a solvent and can be used directly in products. The product is
immersed in a liquid smoke solution. Liquid smoke solution transfers smoke to the
product (Wheaton and Lawson 1985). Compared to conventional smoking methods,
the use of liquid smoke has advantages such as lower cost, less environmental damage, easy availability, and variety of application methods (Hattula et al. 2001).
Moreover, obtaining a uniform smoke aroma is faster and easier than conventional
cold and hot smoking (Varlet et al. 2007). Polycyclic aromatic hydrocarbons (PAHs)
are important carcinogenic compounds formed in smoke that can accumulate on the
surface of smoked foods and then pass into the product. Purification of these compounds is possible by obtaining the natural smoke in either a generator or by condensation of its natural smoke. Liquid smoke is an aqueous solution of natural
smoke condensate and is separated from the tar phase which is inconvenient for
health. In the case of liquid smoke, low concentration of low molecular weight PAH
compounds occur.
In a study in which shrimp (M. reosenbergii) was smoked using liquid smoke,
shrimps were divided into two groups. A group of shrimps were removed from the
head and shells, and the second group of shrimps was removed only from the head.
After that, the shrimps were salted in 30% saline and then smoked using the traditional and liquid smoke methods. At the end of this study, it was reported that flavour and aroma specific for smoked shrimp were more detected in the shrimp
smoked by the traditional method. Shrimp exposed to liquid smoke was characterized by an artificial and bitter taste. In beheaded shrimps treated with liquid smoke,
the characteristic shrimp flavour was more visible (Portella et al. 2011).
2.1 Shrimps/Prawns
ture and time sufficient to cause coagulation of fish proteins. Hot smoking is usually
sufficient to kill parasites, destroy non-spored bacterial pathogens, and eliminate the
spores related to human health (FAO 2013). Hot smoking is the process of smoking
the fish at 70–80 °C and thus cooking the fish. In order to stabilize the smoked product at room temperature, it is reported that the water activity (aw) of the hot smoked
fish products should be less than 0.85 (Arason et al. 2014) Cold method is smoking
of salted fish without exceeding the temperature of 33 °C by avoiding of cooking of
meat and coagulation of proteins. The applied temperature is usually 12–15 °C
(Gokoglu 2002). Cold smoking takes longer than hot smoking but provides higher
efficiency and better protects the original textural properties than hot smoked products (Arason et al. 2014).
Almost any type of hard wood can be used for smoke production. The use of
resinous wood is not suitable as it causes a bitter taste in the product. The choice of
wood depends on the desired odour and taste in the final product. The most preferred wood type is oak. Oak, ash, beech, alder, acacia, poplar, apple, willow,
orange, and lemon trees are stated to be the most suitable trees for smoking.
Coniferous trees are not suitable for smoking. Coniferous trees cause the unpleasant
terpentine taste and odour (Gokoglu 2002).
Liquid smoke solutions, which have been produced with the distillation of the
wood and then concentrated to a certain extent, have been used for many years to
give aroma to the meat and fish (Hattula et al. 2001; Arason et al. 2014). Concentrated
smoke is dissolved in a solvent and can be used directly in products. The product is
immersed in a liquid smoke solution. Liquid smoke solution transfers smoke to the
product (Wheaton and Lawson 1985). Compared to conventional smoking methods,
the use of liquid smoke has advantages such as lower cost, less environmental damage, easy availability, and variety of application methods (Hattula et al. 2001).
Moreover, obtaining a uniform smoke aroma is faster and easier than conventional
cold and hot smoking (Varlet et al. 2007). Polycyclic aromatic hydrocarbons (PAHs)
are important carcinogenic compounds formed in smoke that can accumulate on the
surface of smoked foods and then pass into the product. Purification of these compounds is possible by obtaining the natural smoke in either a generator or by condensation of its natural smoke. Liquid smoke is an aqueous solution of natural
smoke condensate and is separated from the tar phase which is inconvenient for
health. In the case of liquid smoke, low concentration of low molecular weight PAH
compounds occur.
In a study in which shrimp (M. reosenbergii) was smoked using liquid smoke,
shrimps were divided into two groups. A group of shrimps were removed from the
head and shells, and the second group of shrimps was removed only from the head.
After that, the shrimps were salted in 30% saline and then smoked using the traditional and liquid smoke methods. At the end of this study, it was reported that flavour and aroma specific for smoked shrimp were more detected in the shrimp
smoked by the traditional method. Shrimp exposed to liquid smoke was characterized by an artificial and bitter taste. In beheaded shrimps treated with liquid smoke,
the characteristic shrimp flavour was more visible (Portella et al. 2011).
2.1 Shrimps/Prawns