Commercial Freezing Methods
An Explanation of Modern Quick Freezing Processes for Fruits, Vegetables, Etc.
The quality of commercially frozen foods is higher than foods at home for several reasons. A commercial freezer is capable of freezing foods in a matter of minutes. As a result, the food retains its taste, texture, and color, as well as its nutritional value. Also, commercial freezers are much colder than home freezers. In addition, some produce is grown especially for freezing. These vegetable and fruit varieties are chosen because they best retain their quality during the freezing process.
Quick-freezing processes currently in use include the following:
• Multi-Station Plate Forster – Trays holding individual packages of food are placed on hollow metal shelves inside of the Forster cabinet. These metal shelves are then cooled to below-zero temperatures. This system has the ability to maintain close contact by squeezing the packages between the shelves under steady, slight pressure even while the produce expands as much as ten percent.
This method is used for many of the frozen foods available in 10-ounce packages and for boil-in-bag vegetables.
• Air-Blast Freezing Tunnels – The packaged product is placed on trays which are pushed through a freezing tunnel. The belt may be arranged in a spiral while the cold air passes down through the belt. French fries and many IQF (individually quick frozen) products are frozen by this process.
• Fluidized Bed Freezers – In these freezers, cold air is blown up with such force that individual pieces of the product (for example, lima beans, diced carrots, peas) are agitated and float in the stream of cold air.
• Immersion Freezing – Unpackaged products, such as corn-on-the-cob and peas are quickly frozen by being immersed in a refrigerated bath of halocarbon, a liquid approved by the Food & Drug Administration for use in food processing.
• Freeze Flo Process – This is a patented natural process that among other things prevents foods from freezing solid. Freeze Flo involves isolating and controlling the moisture of water content of a product by tightly binding it to natural substances, such as protein, sugar, salt or unsaturated vegetable oils, so that the product is no longer free to crystallize. This process is currently being used for juice concentrates, fruit pies, cream and fruit fillings, filled doughnuts, eclairs and a variety of other desserts.
National Frozen & Refrigerated Foods Association www.nfraweb.org
Courtesy of U.S. Cold Storage