223
immersion in hot water or alkaline solution. It is applied to soften dried squid before
cooking (Zhao et al. 2017). The softening process of dried squid can be carried out
by various dehydration methods. Immersion in alkaline solution is considered the
most effective and common method to promote softening. Alkaline application
destroys various bonds that stabilize the fibre structure, causing structural change
and enhancing water absorption. Appropriate alkaline application is required to
soften the dried squid structure. Alkaline selection and concentration should be
appropriate. Strong alkaline solution damages fibre structure, while weak alkaline
solution increases inter-fibre space and water absorption of muscle fibres (Benjakul
et al. 2000). In a previous study, softening of dried squid in different conditions was
tried to compare raw squid with dried squid. In this study, the necessity of softening
in three stages, namely pre-soaking, alkaline-soaking, and post-soaking, has been
determined to swell dried squid to its original form. The same researchers have
reported that soaking in alkaline solution may cause leakage of low molecular
weight compounds; especially free amino acids, trimethylamine oxide, sarcoplasmic proteins, and myofibrillar proteins (Kugino et al. 1993). In another study,
Benjakul et al. (2000) examined the effect of alkaline application on the textural
properties of squid, and for this purpose they treated the dried squid with different
proportions of sodium hydroxide and sodium carbonate. It has been reported that
the most effective application in terms of appearance and textural properties is
0.15 mol/kg sodium carbonate with a squid/alkaline solution ratio of 1:10 (w/v) for
20 h. In china dried squid are usually softened in water and then the same water is
used for making soup. The remaining softened squid are soaked in alkaline solution
and then soaked in water again. The softened squid become swollen and their mantles become thicker than those of fresh squid (Konishi et al. 2003) (Fig. 3.10).
Brown discolouration change caused by sugar-amino reactions called “maillard
reaction” during processing and subsequent storage in dried squid products is an
important quality problem. It is reported that the sensitivity of squid species to
browning varies according to the species and that neon flying squid and Atlantic
short finned squid species are more sensitive than others. High content of amino
acids, which are the precursors of the maillard reaction, have been shown as the
reason why these squid species are more sensitive to browning (Haard and Arcilla
1985). It has been reported that during drying at 35 °C, the maillard reaction is
observed related to the decrease in proline and taurine amino acids in the squid
(Illex argentinus) mantle and the browning is increased (Tsai et al. 1991). O 2 , light,
heat and water activity are other factors that promote browning. Drying temperature
is an important factor and drying in hot air causes more browning than drying in
cold air (Fu et al. 2007). The water activity of seasoned squid products is usually
between 0.70 and 0.75. In this Aw range, lysine, histidine, and glycine in dried squid
constitute 75% of the total free amino acids and show high browning rates compared to other amino acids. Browning accelerates at 23 °C storage temperature and
increases with the increase in temperature. Since browning increases during prolonged storage of dried squid products, colour is used as an indicator of storage
history. Excessive browning is considered an undesirable situation for consumers
(Yean et al. 1998). It has been reported that air drying temperature affects the
3.2 Cephalopods
immersion in hot water or alkaline solution. It is applied to soften dried squid before
cooking (Zhao et al. 2017). The softening process of dried squid can be carried out
by various dehydration methods. Immersion in alkaline solution is considered the
most effective and common method to promote softening. Alkaline application
destroys various bonds that stabilize the fibre structure, causing structural change
and enhancing water absorption. Appropriate alkaline application is required to
soften the dried squid structure. Alkaline selection and concentration should be
appropriate. Strong alkaline solution damages fibre structure, while weak alkaline
solution increases inter-fibre space and water absorption of muscle fibres (Benjakul
et al. 2000). In a previous study, softening of dried squid in different conditions was
tried to compare raw squid with dried squid. In this study, the necessity of softening
in three stages, namely pre-soaking, alkaline-soaking, and post-soaking, has been
determined to swell dried squid to its original form. The same researchers have
reported that soaking in alkaline solution may cause leakage of low molecular
weight compounds; especially free amino acids, trimethylamine oxide, sarcoplasmic proteins, and myofibrillar proteins (Kugino et al. 1993). In another study,
Benjakul et al. (2000) examined the effect of alkaline application on the textural
properties of squid, and for this purpose they treated the dried squid with different
proportions of sodium hydroxide and sodium carbonate. It has been reported that
the most effective application in terms of appearance and textural properties is
0.15 mol/kg sodium carbonate with a squid/alkaline solution ratio of 1:10 (w/v) for
20 h. In china dried squid are usually softened in water and then the same water is
used for making soup. The remaining softened squid are soaked in alkaline solution
and then soaked in water again. The softened squid become swollen and their mantles become thicker than those of fresh squid (Konishi et al. 2003) (Fig. 3.10).
Brown discolouration change caused by sugar-amino reactions called “maillard
reaction” during processing and subsequent storage in dried squid products is an
important quality problem. It is reported that the sensitivity of squid species to
browning varies according to the species and that neon flying squid and Atlantic
short finned squid species are more sensitive than others. High content of amino
acids, which are the precursors of the maillard reaction, have been shown as the
reason why these squid species are more sensitive to browning (Haard and Arcilla
1985). It has been reported that during drying at 35 °C, the maillard reaction is
observed related to the decrease in proline and taurine amino acids in the squid
(Illex argentinus) mantle and the browning is increased (Tsai et al. 1991). O 2 , light,
heat and water activity are other factors that promote browning. Drying temperature
is an important factor and drying in hot air causes more browning than drying in
cold air (Fu et al. 2007). The water activity of seasoned squid products is usually
between 0.70 and 0.75. In this Aw range, lysine, histidine, and glycine in dried squid
constitute 75% of the total free amino acids and show high browning rates compared to other amino acids. Browning accelerates at 23 °C storage temperature and
increases with the increase in temperature. Since browning increases during prolonged storage of dried squid products, colour is used as an indicator of storage
history. Excessive browning is considered an undesirable situation for consumers
(Yean et al. 1998). It has been reported that air drying temperature affects the
3.2 Cephalopods