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Sun Drying
Traditionally, sea cucumbers are dried using the sun drying technique. However, it
is not possible to use this method continuously. Because it is weather dependent
method and improper weather conditions can cause the product to deteriorate (Ram
2017). In this method, which is based on drying sea cucumber under the sun, capital
and operating costs are low. There are no energy, labour or machine costs. Free solar
energy is used and does not require experienced labour. Water is usually removed by
evaporation (Chong et al. 2015). In the traditionally used sun drying method, sea
cucumber is boiled and then salted, and dried for 3–5 days with solar radiation.
However, this process has negative aspects such as being time consuming, contaminated, and causing loss of many active ingredients (Duan et al. 2007). Moreover,
there is a risk of being invaded by various animals (Chong et al. 2015).
Hot Air Drying
Due to the above-mentioned disadvantages of the sun drying method, the hot airdrying method is a simple and popular method used as an alternative to the sun
drying method. However, it has been reported that hot air-drying causes large product deformations and thermally induced deterioration (Duan et al. 2010; Ratti 2001).
Also in hot air drying, hot air accelerates the drying of the sea cucumber surface and
causes a surface hardening and so this hardening prevents the transfer of moisture
from the body wall and can cause serious cracking of the surface and poor sea
cucumber quality (Moon et al. 2014).
Freeze Drying
The greatest advantage of freeze-dried sea cucumbers is that they are ready to eat
after simple rehydration. Moreover, they can be kept fresh without any additive or
preservative. The whole processing procedure is carried out below the freezing
point under vacuum (no oxygen), with minimal loss of bioactive components, and
lower final moisture content. With their colour, shape, and nutrients preserved, these
sea cucumbers will have the same taste as fresh sea cucumbers after rehydration
(Mao et al. 2015).
In a study, it has been shown that freeze drying method can be used for seafood
(Yun et al. 2006). Although this method is an excellent method, it has been reported
that takes a long processing time and energy consumption and investment expenses
are high (Ratti 2001). Duan et al. (2010) developed a microwave freeze drying technique for sea cucumber (Stichopus japonicus). They reported that the microwave
freeze dryer reduces the drying time by half the conventional freeze drying process
and offers a quality product similar to freeze-dried and for this reason can replace
the microwave freeze drying method with the conventional freeze drying method.
Although microwave freeze drying can significantly increase the drying speed, in
this technology, it is reported that the naturally in homogeneous distribution of the
4 Echinoderms
Sun Drying
Traditionally, sea cucumbers are dried using the sun drying technique. However, it
is not possible to use this method continuously. Because it is weather dependent
method and improper weather conditions can cause the product to deteriorate (Ram
2017). In this method, which is based on drying sea cucumber under the sun, capital
and operating costs are low. There are no energy, labour or machine costs. Free solar
energy is used and does not require experienced labour. Water is usually removed by
evaporation (Chong et al. 2015). In the traditionally used sun drying method, sea
cucumber is boiled and then salted, and dried for 3–5 days with solar radiation.
However, this process has negative aspects such as being time consuming, contaminated, and causing loss of many active ingredients (Duan et al. 2007). Moreover,
there is a risk of being invaded by various animals (Chong et al. 2015).
Hot Air Drying
Due to the above-mentioned disadvantages of the sun drying method, the hot airdrying method is a simple and popular method used as an alternative to the sun
drying method. However, it has been reported that hot air-drying causes large product deformations and thermally induced deterioration (Duan et al. 2010; Ratti 2001).
Also in hot air drying, hot air accelerates the drying of the sea cucumber surface and
causes a surface hardening and so this hardening prevents the transfer of moisture
from the body wall and can cause serious cracking of the surface and poor sea
cucumber quality (Moon et al. 2014).
Freeze Drying
The greatest advantage of freeze-dried sea cucumbers is that they are ready to eat
after simple rehydration. Moreover, they can be kept fresh without any additive or
preservative. The whole processing procedure is carried out below the freezing
point under vacuum (no oxygen), with minimal loss of bioactive components, and
lower final moisture content. With their colour, shape, and nutrients preserved, these
sea cucumbers will have the same taste as fresh sea cucumbers after rehydration
(Mao et al. 2015).
In a study, it has been shown that freeze drying method can be used for seafood
(Yun et al. 2006). Although this method is an excellent method, it has been reported
that takes a long processing time and energy consumption and investment expenses
are high (Ratti 2001). Duan et al. (2010) developed a microwave freeze drying technique for sea cucumber (Stichopus japonicus). They reported that the microwave
freeze dryer reduces the drying time by half the conventional freeze drying process
and offers a quality product similar to freeze-dried and for this reason can replace
the microwave freeze drying method with the conventional freeze drying method.
Although microwave freeze drying can significantly increase the drying speed, in
this technology, it is reported that the naturally in homogeneous distribution of the
4 Echinoderms