Freezing Technology

3.4.1. Brining

To minimize drip loss, fillets/steaks of fish are immersed in brine for a short time and this process is known as firming of fillets/steaks. There are several advantages in this type of firming.

1. When fish fillets are dipped in strong brine, the proteins in the outer surface of the fillet gets coagulated due to which firming takes place.
2. The layer of salted out proteins insulates the muscle tissues from the negative influence of outside factors.
3. It favours the retention and preservation of natural extractives and flavour compounds.
4. It minimized drip loss.

Effect of salt concentration in brine and brining time

The treatment of fish fillets with brine is a precision operation. When the salt concentration is less than 5% proteins get solubilized and lost in salt solution. If it is more than 15%, tissue proteins coagulate due to “salting out” of the proteins and the texture becomes tough. If the duration of dip treatment is more, the product becomes salty. Therefore, brining treatment should be done in right concentration for a brief period of time.

Method of brining: Before the treatment with brine, the fillets are washed properly, because brine treatment on a clean surface is more effective. Salt concentration in brine should be 10-12% (sp. gr. 1.07 to 1.09). Brining temperature should be less than 15^OC. In dip treatment the brining time is 1 to 2 min. However, there is scope to change the salt concentration and duration of time for treatment depending on species of fish. The brine should be changed after every dip treatment. Addition of antimicrobials such as sodium benzoate, benzoic acid, parabens, sodium nitrite and antioxidants like ascorbic acid can be added to brine in order to maximize its effectiveness. However in fatty fish bringing promotes fat oxidation in it and hence the results are not encouraging.

Effect of salt concentration in brine and brining time

The treatment of fish fillets with brine is a precision operation. When the salt concentration is less than 5% proteins get solubilized and lost in salt solution. If it is more than 15%, tissue proteins coagulate due to “salting out” of the proteins and the texture becomes tough. If the duration of dip treatment is more, the product becomes salty. Therefore, brining treatment should be done in right concentration for a brief period of time.

Method of brining: Before the treatment with brine, the fillets are washed properly, because brine treatment on a clean surface is more effective. Salt concentration in brine should be 10-12% (sp. gr. 1.07 to 1.09). Brining temperature should be less than 15^OC. In dip treatment the brining time is 1 to 2 min. However, there is scope to change the salt concentration and duration of time for treatment depending on species of fish. The brine should be changed after every dip treatment. Addition of antimicrobials such as sodium benzoate, benzoic acid, parabens, sodium nitrite and antioxidants like ascorbic acid can be added to brine in order to maximize its effectiveness. However in fatty fish bringing promotes fat oxidation in it and hence the results are not encouraging.