In-line cryogenic freezing: a tailored solution

Time is of the essence when it comes to freezing. Cryogenic freezing is a niche application in the food refrigeration market and refers mainly to the use of liquid nitrogen and liquid carbon dioxide as the refrigeration mediums. The colder temperatures of these cryogens enhance the quality of the food product by freezing it much faster than with traditional freezing methods. Faster freezing results in the formation of smaller ice crystals which causes less damage to the cellular structure and helps to retain the food product’s initial texture, colour and flavour attributes. In addition, cryogenic freezing contributes to higher yields by rapidly locking in the product’s moisture content so that there is very little weight loss from dehydration during the freezing process.

Integrating a cryogenic freezing solution into a new or existing production line involves a good understanding of the composition and properties of the food product that needs to be frozen, along with the production parameters and the production floor layout. Air Liquide has extensive technical knowledge and expertise, through its worldwide network of food cryogenic specialists and research laboratories, to be able to design the most cost-efficient cryogenic solution that is customized to meet the specific needs of each manufacturer. Air Liquide also offers an extensive range of cryogenic food processing equipment, in various models, widths and lengths, that can be perfectly matched with the food product, production volumes and amount of available floor space.

Cryogenic freezing equipment solutions are extremely flexible and can be easily customized based on the different characteristics of the food product. For example, the conveyor belt that is selected for a cryogenic freezer is chosen based on the type of food product that is being frozen. There are several different types of conveyor belts that are available, each with its own particular set of attributes: stainless steel mesh conveyor belts; stainless steel plate-link belts and food-grade polyester conveyor belts.

Stainless steel mesh belts are used for the majority of the cryogenic food freezing applications since they are available in different mesh opening sizes which can minimize any product losses in the cryogenic freezer while still allowing the cold gases to circulate more evenly around the food product for better freezing efficiencies. However, there are instances where the product is too small (ie, grated cheese, cooked pizza toppings) for even a very fine mesh opening conveyor belt. In these particular cases, the product can clog up the belt mesh or even fall through the mesh openings, creating unnecessary product losses inside the freezer. In order to avoid these kinds of issues, a stainless steel plate-link or polyester belt is better suited for these types of products since these are ‘solid-type’ belt materials that will ensure that the product stays on the conveyor and is carried through the freezer without any losses.

Food products with fragile, soft or sticky characteristics (ie, marinated chicken breasts, chocolate-coated products), can quite often stick to stainless steel conveyor belts, either leaving belt marks on the product or making it difficult to remove the product without any damage or deformation. Using a solid non-metal belt material like Air Liquide’s food-grade polyester belt, is a great alternative. This belt is saturated with liquid nitrogen using an innovative, patented liquid nitrogen belt wetting technique that enhances the overall freezing process. The bottom surface of the product, when placed onto the polyester belt, freezes immediately which prevents any sticking to the belt so that belt marking is reduced, and product deformation or damage is eliminated.

Air Liquide has been providing innovative solutions to the food industry throughout the world for over 50 years. Every solution is specifically designed for each food processor using Air Liquide’s ALIGAL^TM food-grade gases, state-of-the-art application equipment and food cryogenic technical support services. Air Liquide customers benefit from being able to produce value-added, high quality food products at a competitive cost.

For more information, please visit: https://industry.airliquide.com.au/industries/food.

Top image caption: Typical cryogenic freezer installation layout