11.8 Applications
255
Although much of the enzymes which act on the fish protein to produce fish sauce
are the endogenous enzymes, some bacterial activity, particularly in the first 3 weeks,
does result in the production of fatty acids and other metabolites which contribute
to the distinct flavor of fish sauce (Kim et al. 2002). These are likely the halophiles
which can survive the high salinity. The activity of trypsin and chymotrypsin is
significantly reduced during the process due to the high salinity; however, the activity of these enzymes is still important to the production of fish sauce. Proteolytic
enzymes remain at maximal activity throughout the process. The level of activity
of the microorganisms or enzymes is also dependent on the species of fish and the
conditions.
The activities of these enzymes can be accelerated by either increasing the pH to
alkaline conditions, reducing the pH to higher acidity which accelerates hydrolysis
or increasing the temperature to 45 °C which is high enough to accelerate the process
but without denaturing the enzyme. At the varied pH, certain enzymes which promote
the breakdown of the fish proteins will be enhanced. For example, at higher pH and
lower salinity trypsin, chymotrypsin and alkaline proteinase are more active. These
methods could reduce the fermentation time by about 80%; however, taste of the
resulting sauce is often inferior to that at longer period.
Fish protein hydrolysate is produced by treating the fish with only proteolytic
enzymes. The proteolytic enzymes specifically act on the peptide bonds. In the process of production of fish protein hydrolysate, other enzymes are inactivated in order
to ensure only the proteolytic enzymes act on the fish protein. This results in the
production of soluble protein which is then separated, concentrated and dried.
Enzymes can also be used to process the wastewater from cooking or processing of fish and marine invertebrates into fish products such as sauces and protein
hydrolysate. This further aids the optimal utilization of the aquatic resources.
11.8.7 Caviar Production
Caviar is one of the high-value food products from fish. It is produced from the
roe of primarily sturgeon and other fishes such as herring, salmon, cod, trout and
catfish. The key challenge in caviar production is the separation of the roe from the
connective tissue which links it to the parent body. The process of removing the roe
from the connective tissue is referred to as riddling (Kim et al. 2002). This leads to
higher cost of production in terms of time and man power. The time and complexity of
this process can be reduced by using proteolytic enzymes. The enzymes break down
the connective tissue leaving behind the eggs used for caviar. Using this method
compared to conventional riddling method can achieve up to 20% improvement in
yield (Kim et al. 2002). The yield is a measure of how much of the roe is successfully
riddled without damage to the egg. The process is quite delicate; if not carefully done,
the egg is damaged; and typically, over half of the eggs are damaged in the riddling
process. The enzyme method minimizes the mechanical stress on the egg, resulting
in hire successful riddling. This has significant economic impact on the producer as
255
Although much of the enzymes which act on the fish protein to produce fish sauce
are the endogenous enzymes, some bacterial activity, particularly in the first 3 weeks,
does result in the production of fatty acids and other metabolites which contribute
to the distinct flavor of fish sauce (Kim et al. 2002). These are likely the halophiles
which can survive the high salinity. The activity of trypsin and chymotrypsin is
significantly reduced during the process due to the high salinity; however, the activity of these enzymes is still important to the production of fish sauce. Proteolytic
enzymes remain at maximal activity throughout the process. The level of activity
of the microorganisms or enzymes is also dependent on the species of fish and the
conditions.
The activities of these enzymes can be accelerated by either increasing the pH to
alkaline conditions, reducing the pH to higher acidity which accelerates hydrolysis
or increasing the temperature to 45 °C which is high enough to accelerate the process
but without denaturing the enzyme. At the varied pH, certain enzymes which promote
the breakdown of the fish proteins will be enhanced. For example, at higher pH and
lower salinity trypsin, chymotrypsin and alkaline proteinase are more active. These
methods could reduce the fermentation time by about 80%; however, taste of the
resulting sauce is often inferior to that at longer period.
Fish protein hydrolysate is produced by treating the fish with only proteolytic
enzymes. The proteolytic enzymes specifically act on the peptide bonds. In the process of production of fish protein hydrolysate, other enzymes are inactivated in order
to ensure only the proteolytic enzymes act on the fish protein. This results in the
production of soluble protein which is then separated, concentrated and dried.
Enzymes can also be used to process the wastewater from cooking or processing of fish and marine invertebrates into fish products such as sauces and protein
hydrolysate. This further aids the optimal utilization of the aquatic resources.
11.8.7 Caviar Production
Caviar is one of the high-value food products from fish. It is produced from the
roe of primarily sturgeon and other fishes such as herring, salmon, cod, trout and
catfish. The key challenge in caviar production is the separation of the roe from the
connective tissue which links it to the parent body. The process of removing the roe
from the connective tissue is referred to as riddling (Kim et al. 2002). This leads to
higher cost of production in terms of time and man power. The time and complexity of
this process can be reduced by using proteolytic enzymes. The enzymes break down
the connective tissue leaving behind the eggs used for caviar. Using this method
compared to conventional riddling method can achieve up to 20% improvement in
yield (Kim et al. 2002). The yield is a measure of how much of the roe is successfully
riddled without damage to the egg. The process is quite delicate; if not carefully done,
the egg is damaged; and typically, over half of the eggs are damaged in the riddling
process. The enzyme method minimizes the mechanical stress on the egg, resulting
in hire successful riddling. This has significant economic impact on the producer as