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Freezing is the process of reducing/removing humidity from a defined area or product. What your airconditioners do is exactly the same (You now know the reason why your air conditioner is continuously dripping water)

This holds good for fish freezing also. Since the process of freezing by design removes the humidity or water content and in order to ensure that the fish being frozen does not become dry in this process and the juices of the meat remain intact, it is completely draped in polythene cover with out any gaps to see that no chilled air comes in contact with the fish. Even after the freezing process, the fish is actually stored in a fully wrapped polythene cover. It is a common sight to find fish stored in cold stores becoming dry because the polythene cover is torn. (This is referred to as freeze burns, which it is not)

However, this measure is good for the time of freezing, but when fish is stored in cold stores at temperatures less than -18 degrees centigrade for prolonged periods of time, it is not fool proof enough. The temperature in cold store does not remain constant and is prone to fluctuations say for example when a product is being loaded into the cold store and unloaded, the doors of the store are kept open for long periods of time resulting in increase in the temperature. Once the doors are closed, the compressors start working to bring down the temperature to the desired level. In this process moisture in the store is sucked out and if the products are unprotected (not covered with polythene or card board) they will become dry. The more such temperature fluctuations, higher the probability of the product becoming dry. So, in order to ensure retention of the moisture content in the fish even while stored in the cold stores, a technique called glazing is used. Glazing is nothing but creating a layer of ice around the product. The product is dipped in water soon after it is frozen. Owing to low humidity due to the low temperature on the surface of the frozen product, water is absorbed by the product and since the product temperature is around -40 immediately becomes ice forming an outer layer. Now longer the dip in the water higher the glaze. A simple and quick one time dip should give the product a weight gain of 5%, Two dips would give a weight gain of 10% and so on.

It is not uncommon to find Vietnam Basa with 20% glaze and some prawns at 20 or 30 percent glaze.

Now there are two kinds of glazing. 1) Protective Glaze 2)Commercial Glaze.

Protective glaze generally does not exceed 5% and is intended to retain moisture in the product Commercial glaze on the other hand is intended to make the product appear less costlier than that of competitors.

Sample this example. If a zero glazed product cost Rs. 100, 10% glazed product would cost 90 and a 20% one would cost 80 and if the buyer is unaware he would think that the product which is 80 is cheaper while it actually is not.

Once the product is thawed, what remains is the actual weight.