During the past two years, the Spanish Marine Investigation Institute of Vigo (MII) has been developing a conservation method by use of liquid ice to preserve the marine species of commercial value. The liquid ice is to increase the quality and freshness of chilled fish, preserving it for a longer period of time than traditional techniques.
Fish products are highly perishable, mainly because of the deterioration process it experiences one the fish has been caught and therefore retrieved from its natural environment. The purpose of the study is to develop a better preservation method which would resolve this process, said MII coordinator of the project, Santiago Aubourg.
â€The research and development of emerging technologies to preserve fish products is one of the most important existing challenges for food technologistsâ€, he said.
Traditionally, fish was chilled by adding ice flakes. During the last years, refrigeration techniques have advanced greatly with the addition of salt to the ice-water mix, reaching temperatures below 0 degrees C. Liquid ice consists of clear round spherical crystals, which are finely dispersed in an anti-freeze solution. It is produced by a process, which continuously stirs the generated ice so that it is suspended in the form of microscopic crystals in the solution. The ice-water proportion can vary between 20 and 40 %, depending on the size of the marine species to be preserved. Besides the great advantage of preserving products below 0 degrees C, thermal conductivity through liquid ice is higher than through ice flakes. Its versatile production techniques also enables a combination other preserving agents.
The results show that fish is preserved for a 10-day longer period when using liquid ice compared to when using ice flakes.