Have you ever wondered why store brought and frozen fish have a pungent fishy odour?
Water in the ocean is about 3% salt by weight. The amount of dissolved mineral including sodium chloride in the fish cells is less than 1%. In order to balance the saltiness in the seawater, ocean creatures fills their cells with amino acids and amines. There are 20 amino acids that make up proteins. The shellfish are filled with amino acid glycine, which is sweet and glutamic acid in the form monosodium glutamate, which is savory and filling. Whereas, the fish has some amino acid but it is mostly dominated with trimethylamine oxide. Now, when fish gets killed the bacteria and enzyme in the fish triggers an oxidation-reduction reaction. This results in trimethylamine and later in to ammonia causing the fish to have strong odour, as it gets older.
On other hand have you thought why fish gets cooked in jiffy getting transformed from translucent to opaque, I can’t wait to write on it, but it we shall leave it for next fish post.
Since my childhood I have been a fish lover, especially when it gets cooked in tangy tamarind sauce. I have tweaked this recipe by not completely using the tamarind juice but by substituting half of it with tomato. Keep it as weekend lunch with good warm rice, I bet you will fall in love!
Before I get back to you on the science behind cooking time, please make sure not to over cook the fish, there is a fine line between almost done to over cooked. Turnoff the heat a bit in advance as you know your pot, pan and the sauce is still boiling hot! That is good enough to cook your fish just right!
Reference: On Food and Cooking: The Science and Lore of the Kitchen – By Harold McGee