Fish Products and Byproducts Technology

Unit 9 - Fish meal and fish oil

9.5.2. Dry reduction/rendering process
The dry reduction process is principally applied to the conversion of fish or fish offal of low fat content. It is a batch process and is easier to manipulate than the wet rendering which is a continuous process. The essential steps in dry reduction process are as follows:

• Fish are coarsely ground in a hacker or grinder
• The hacked fish are cooked in a steam jacketed cooker with a stirrer.
• The cooker also acts as a drier and is usually referred as cooker/ drier. Presser and separate drier or optional extras with this type of plant the cooker/drier may be operated at atmospheric pressure or under slight vacuum to facilitate drying.

Advantages and disadvantages of Dry reduction process