Not really.
If you take fresh food, put in a plastic bag and pop it into the freezer, the food stays fresh for many months. The plastic bag is required to prevent ice crystals coming into contact with the food. If ice crystals come into contact with the food, you get what is called a ‘freezer burn’. Freezer burn breaches the ‘skin’ of the food and damages the food as well so that when it is de-frozen, the food becomes mushy, spoilt and virtually inedible. If food is properly protected prior to inserting into the freezer, it would be like putting it into a nutritional time-warp.
This means that all nutrients that were present in the food at the time of freezing stay virtually the same.
Remember the operative word here is ‘fresh’. Food that is purchased at the local supermarket might have already been through some freezer earlier also, heaven knows how long it has been sitting on the shelf. So by ‘fresh’ I mean as in caught / slaughtered an hour earlier.
The sooner it enters cold storage, the better the nutritional value.
Often times, fish is caught in the high seas and directly deep-frozen on board the ship. When it arrives on the dock it is transferred to an onshore deep-freeze facility and from there via refrigerated trucks to the super markets. Throughout this journey, the fish needs to remain frozen it must never reach room temperature.
So, as long as it remains frozen, the ‘cold chain’ is said to have been maintained – all is good.
If frozen food is de-frozen and put on the super market shelves then it cannot be refrozen after reaching your home – it needs to be consumed.
What about frozen fruits and veggies?
Fruits and veggies have large water content. As we know, water expands when frozen. So if you put fruits and veggies in a freezer, it will expand the water in the food and damage the cell walls in the fruit or vegetable. When you de-freeze it, the frozen water within the fruit or vegetable melts and renders the food useless.
Can frozen foods be better than fresh?
Yes, if the food is instantly frozen before it begins to decompose. However, from a taste point-of-view, freshly caught fish tastes better than frozen fish. The reason for this is that there usually is a time lag before the fish is frozen – time enough for the fish to begin decomposing. The process gets arrested the moment the fish enters the freezer.