What are the differences between Individually Quick Freezing and Slow Freezing?
IQF is a technology that allows the freezing on an individual piece of product separately from the others. Due to this, the quality of the finished IQF product is superior compared to that of a product frozen by cold store freezing.
The main difference is the size and quantity of the frozen product; cold store freezing is used for large volumes of bigger sized products such as whole chicken or packed meat. IQF, on the other hand, is ideal for freezing smaller products such as small fruit, fruit cubes, vegetables, shrimp, cheese, pasta, etc. IQF technology implies placing the product inside a freezer that makes better use of thermodynamics by continuously moving the product. IQF freezes the product faster to the core.
Using IQF technology will significantly reduce the ice formation on the product, due to the fact that the product is frozen fast. This leads to much smaller ice crystals compared to cold Store Freezing. Slow freezing causes large ice crystals to form, and this affects the integrity of the products’ cells, stretching the membrane. The larger the crystals, the more damage the product will suffer. The deterioration is irreversible, meaning that the texture of the product will not return to a more natural state after thawing. With IQF there is minimal formation of ice crystals, and this will help the product keep its texture until first defrost.
Products from cold storage freezing also experience a lot of drip loss, loss of texture and nutrients after the first thaw. These are not the only issues caused by ice crystals. Another problem caused by this ice formation is dehydration. Due to the length of the freezing process, the product suffers from water loss through sublimation (when water turns to gas from solid form), speeding up the freezing process can help the reduction of dehydration, this is why by using IQF technology, the dehydration rate is somewhere between 0.3% to 2% whereas with cold storage freezing the dehydration rate is frequently somewhere between 7% - 11%, this is a direct loss of the quality of the product.
The loss in color is another characteristic frequent of cold storage freezing. Even if the color is more vibrant that of the frozen product with cold storage freezing; when it thaws, the product loses its’ vibrant color and gets a more grayish tone. This discoloration can be avoided. The signs of quality freezing with IQF technology is a rather pale and white colored product when frozen that returns to have a natural look when thawed.
With IQF technology the product has a more natural color and texture that stays relatively unchanged after the first defrost.
When we put our food in the freezer we notice that it tends to stick together when frozen. This issue is also observed in cold storage freezing when products form large ice formation around themselves and get stuck to each other requiring more force to disconnect them. This also depends a lot on the size and the stickiness of the products. During the IQF process, the products are frozen much faster and separate from each other, which do not allow them to stick together and will remain like that until first defrost.
By using IQF technology, the products keep their initial shape without any damage to the surface, and have a higher shelf life. This is because the product does not get exposed to as much air in the IQF freezer.
One of the most important aspects of freezing with IQF technology is food safety. With a modern in-line process and an IQF freezer, it is possible to achieve up to zero contact between the product and the workers in comparison with Cold Store where due to extensive manual handling and exposure there is a considerable risk for contamination when freezing products.
IQF Shrimp have a shelf life of 18 months. (Nissui Marine Resources)
You can defrost frozen shrimp quickly by submerging it in cold water. Alternatively, you can place frozen shrimp in a covered bowl and allow them to thaw in your refrigerator overnight.
Overall using the IQF instead of cold storage freezing is more cost efficient. The benefits are:
1. Better quality products
2. Better texture
3. The final product has more nutrients
4. Better aspect
5. Virtually no loss in taste compared to fresh product.