INDUSTRIAL THAWING OF BLOCK FROZEN FISH PRODUCTS - TO IMPROVE QUALITY, YIELD AND CAPACITY

摘要

The fact that supply of fresh raw material often is dependent on seasonal variations, weather conditions, quotes and regulations, has been a great incentive to use frozen raw material in the fish process industry. The raw material is often frozen in plate freezers or carton boxes, leading to brick shaped blocks of frozen raw material. Thawing of these blocks represent challenges, both in terms of handling and in thermal aspects. The blocks tend to freeze together forming larger units. This means that the thawing must last significantly longer than theoretically necessary. An important mean to reduce the thawing time and to improve the quality is to split the blocks as soon as possible. This work investigates the effect of some factors (thawing media temperature, salt content in thawing media, agitation, initial temperature of the block), and suggests how this knowledge can be used to improve existing thawing processes.