Cooling & Freezing
The cooling and freezing of food products occurs at various points in the manufacturing process. Depending on the product and time and space capacities, this can be done continuously or batch wise. The objectives of the cooling process can be varied: for the hardening of product surfaces, for cooling above the freezing point or for the freezing of the products.
Although freezing is by far one of the best methods for conserving food products, improper slow freezing or an irregular drop in temperature can lead to the creation of large ice crystals and damage to cell walls and muscle fibres. When later defrosted, the food loses a part of the cell liquid and thus suffers loss in nutritional value, taste and consistency. The freezing speed depends, on the one hand on the nature of the product and on the other on the conditions in the freezer. The product itself influences the freezing speed through water content, ingredients, starting temperature, product density and shape, surface type and heat conductivity.
A high freezing rate of more than 5 cm/h is achieved with liquid nitrogen (LN2) or liquid carbon dioxide (LCO2) as a freezing medium, so that the cell structure of the frozen food is preserved through the fine-crystalline freezing of the water portion. This means that after defrosting no losses in cell liquid content occur. A further advantage is the prevention of dehydration and thus undesirable weight loss during the freezing process through rapid freezing of the product surface.
- Higher product turnover through short freezing times
- High quality of frozen products
- No dehydration losses
- Fast operation
- Low investment costs
- Takes up little space
- High plant
- Low maintenance and repair costs (simple plant construction)
Messer, in co-operation with renowned hardware manufacturers, offers an extensive range of freezers for cryogenic freezing, such as tunnel freezers and spiral freezers as well as cabinet freezers.