Food processing: quick freezing

The two basic ways to achieve the freezing of foods are quick and slow freezing. The technical features of the quick freezing process are ultra rapid freezing at very low temperatures (-30 to -40 ° C) designed to bring the inside the product to a temperature of -18°C as quickly as possible. Rapidly frozen foods have a much longer storage life than foods stored in cold stores.

The products that are generally preserved by quick freezing are meat, fish, some vegetables such as peas, spinach, cauliflower, carrots, beans etc.

When the quick freezing process is used, these liquids solidify to form extremely fine crystals of ice, and the cellular structure is left intact, whereas, in the ordinary freezing process, where low temperatures are reaching more slowly, the texture of the product is altered.

In quick freezing, large quantity of food can be frozen in a short period of time.

Quick freezing is a method of increasing the shelf-life of perishable foods by subjecting them to conditions of temperature low enough to inhibit the oxidative, enzymatic and microbial changes, which are responsible for the changes in flavor and color of foods.

Quick freezing is ideal for producing good quality frozen foods. The food freezes immediately and keeps its shape and appearance.

Quick freezing is obtained by one of the following methods:
*Freezing Tunnel or Blast Freezer
*By Direct Contact with Metal Plate Surfaces maintained at Low Temperatures
*By immersion in (or by Spraying)  a Low Temperature Liquid
Food processing: quick freezing