Salted and salted and dried fish (hereafter clipfish) are among the most important export products in Norwegian seafood industry. Before consumption these products must be soaked in water (desalted) for several days. Different types of ready-to-use desalted products are becoming more and more normal to find in the main markets for there products. Norwegian producers of clipfish have lost shares in important markets the last years because they only to a little extent produce ready-to-use products. The main aim of this project was to develop high quality desalted products, both fresh and frozen, through profitable and sustainable process and product development. The main tasks in the project was to optimize desalting technology and methods, as well as develop new packing technologies and high-pressure treatment for prolonged shelf life of desalted products. In the project large pieces of lombos (app. 500 grams) and postas (app. 300 grams) with skin and bone were selected. The reason for this choice was the demand for this type of product in one of the producers` main markets.
Small scale desalting trials (app. 30 litre tanks) showed that the chosen fish pieces needed long time to become desalted. Using tradition methods, only postas were enough desalted within four days. A large difference was found in the salt content between outer layers and core samples of muscle. The outer layer contained too little salt while the core was too salty after four days of desalting. Weight yields decreased with increasing number of water exchanges during desalting. The reduction of water exchanges did not increase the muscle salt content considerably. Small scale trials were followed up by pilot scale desalting (app. 300 litre tanks) at the production plant. Frequent water exchanges resulted is desalted samples of postas and lombos after three and four days, respectively. The yield increase was low (17-18 %) and the outer layer was too much desalted while the core still was too salty. Increased water temperature during desalting did not increase the desalting speed, but a considerable higher bacterial load in the water was registered. Desalting without water exchanges resulted in a higher weight gain (app. 8 %). The outer layers were desalted properly while the core contained too much salt after desalting of postas and lombos for 3 three and four days, respectively. The increased weight gain recorded in desalting without water exchanges is probably due to swelling of muscle proteins. Both chilled storage and freezing/thawing evens the differences in salt content between cores and outer layer.
Several favourable aspects with desalting without or with fewer water exchanges; higher weight yields, less laborious and water demanding, increased efficiency, a more even distribution of salt and potentially higher sensory quality. Based on this, it is recommended to investigate the principle with desalting without (or a few) water changes in industrial scale desalting.
Desalted clipfish has a relatively short shelf life after the desalting process. To increase the shelf life the product can e.g. be frozen, packed in different ways and processed by high pressure processing (HPP). The desalted cod was treated by HPP at different pressure levels (400, 500 and 600 MP) and different holding times (2, 5 and 10 min). Combining HPP and different packaging regimes was also carried out. The results showed that a shelf life of minimum 50 days can be obtained by treating the desalted cod by HPP. Freezing-thawing experiments of desalted cod showed that exposing the desalted fish to CO2 before freezing gave a better shelf life after thawing compared to only freezing and then thawing.
The new knowledge that this project has generated will be important building blocks in the further development of a profitable and sustainable industrial production of ready-to-use clipfish products in Norway. Increasing the processing degree will elevate the income and competitiveness of this industry, but also contribute to growth in other industries as fisheries, process equipment companies and secure valuable jobs in the Norwegian districts.
Klippfisk er et av våre mest kjente eksportprodukt, hvor fremstillingen er basert på norsk råstoff fra bærekraftige, marine ressurser. Klippfisk står for rundt 2/3 av den årlige eksportverdien for salt- og klippfisk, og tilsvarer årlig hele 5 mrd. kroner. Store samfunnsendringer i de viktigste markedene Brasil og Portugal gjør at kunder i større grad enn før etterspør produkter som forenkler tilberedning av tradisjonell klippfisk. Norsk klippfiskindustri opplever nå sterk konkurranse fra lavkostland som Kina og Portugal, og har i løpet av de siste fem årene har tapt store markedsandeler til fordel for utvannede klippfiskprodukt fra disse landene. Næringen står foran en omstilling for å møte utfordringen. Brødrene Sperre AS står for rundt 14 % av den årlige produksjonen av salt- og klippfisk i Norge, og ønsker å utvikle prosesser for produksjon av industrielt utvannet salt- og klippfiskprodukt (CoPro) med norsk råstoff, i Norge. Dette krever ny kompetanse langs hele verdikjeden. Prosjektet har et tverrfaglig konsortium av relevante industriaktører og FoU-miljø. Prosjektet søker å utvikle lønnsomme og bærekraftige prosesser som kan gi produksjon av konkurransedyktige CoPro for nåværende og fremtidige marked. Det fokuseres på prosesser som industriell utvanning og innovativ pakketeknologi for å ivareta karakteristiske sensoriske parametere og samtidig lang holdbarhet. Det skal utføres pilotskalaforsøk for kartlegging av viktige parametere, før man i samarbeid med teknologileverandører (Optimarstette AS, Vartdal Plastindustri AS) kan utvikle prosesser for industriskalaproduksjon. Bacalaofabrikken AS bidrar med erfaring med småskalaproduksjon av CoPro for det norske markedet. For lønnsom drift vil automatisering av prosesser være viktig. FoU-partnere (Møreforsking AS, Nofima AS, ANFACO) har lang erfaring med ulike prosjekter på salt- og klippfisk og vil gjennomføre forskning i alle prosessledd, med førstehåndskunnskap om råstoffbehandling, utvannings- og pakketeknologi.