A Dramatic Breakthrough in Fish Meal Production from Industrial Fish and from Human Consumption Fish Processing Waste and Rejects

The process by which 6 million MT of fish meal and 1 million MT of fish oil are produced each year has seen little fundamental change in the past 50 years. In fact, a significant proportion of industrial processing still uses 50-year-old technology.

The main improvements made have been in more gentle drying of the presscake, together with the incorporation of the whole of the stickwater, as concentrate, in the feed to the dryer. The finished product “whole meal” represents the proximate analysis of the whole fish raw material after the removal of the optimum amount of free oil in the stickwater by centrifuge. The only significant controllable variables in the fish meal and fish oil proximate analysis have been determined by the freshness of the raw material, and its degree of autolysis.

With the introduction of Tandem Stream processing by AKT International Pty. Ltd., an extremely flexible processing system becomes possible, with control of the proximate analysis of the finished products.

This is made possible by the use of the new flash evaporator with a centrifugal fluid bed dryer for liquids, including stickwater, solubles, or hydrolysates. This unit is integrated into the dehydrator and operates in tandem (parallel) with a separate stream handling moist solids such as presscake, and decanter solids, bones, and scales. The dehydration in this second stream is performed by the long established and well known KIX flash dryer.

The products of the Tandem Stream process are the two dry, finely divided meals from the KIX flash dryer and the KIX fluid bed flash evaporator respectively. These two meals may be combined to a homogeneous mixture in any desired proportions, thus allowing the proximate analysis, particularly as regards protein, ash and soluble protein to be controlled precisely. If desired, the two streams may be packaged and sold separately, as a premium high protein/low ash/high water soluble meal, and a higher ash/lower protein/lower water soluble protein meal respectively.

It has been found that the lipids in these meals are partially encapsulated within the protein, thus significantly reducing the amount of antioxidant which has to be used for the same shelf life.

In the fish meal industry worldwide, there is new emphasis on by-product recovery from material emanating out of the human consumption processing of fish. The new Tandem Stream process is uniquely suited to the effective processing of “waste” from human consumption processing, and most importantly with 100% recovery. The comprehensive flexibility of the Tandem Stream KIX process is even more clearly demonstrated here than in the industrial process. This flexibility is possible both before and after the oil separation and dehydration processes.

By-product raw material (cuttings, reject whole fish, heads, tails, and viscera) can be subject to partial or complete hydrolysis or autolysis, with screening or centrifuging of the hydrolysate or autolysate before the dehydration processes. This allows even more distinct end products to be produced—bone meal, whole meal, dehydrated hydrolysate, blends. It should be noted that the KIX flash evaporator product is subject to even lower thermodynamic exposure than in spray drying.

It is clear that the KIX Tandem Stream process can be applied both in traditional industrial fish meal processing, and in the by-product process discussed above. With the increased emphasis on sustainability and responsible management of all fisheries, by-product fish meals will become increasingly important, and the KIX Tandem Stream process is ideally suited to the scale of operation of by-product recovery. As the system is modular, any scale of operation can be accommodated.

Apart from full flexibility, exceptional product quality and digestibility, the KIX Tandem Stream plants are simple, very compact, and low in capital cost.

Further details:

     AKT International Pty. Ltd.
     GPO Box 3122
     Sydney NSW 2001

     Phone/Fax  +61-2-9929-2177
     e-mail:  sydney@akt-kix.com
     En Español:  castellano@akt-kix.com

John S. Kilpatrick
October 2006