From cooked shrimp compounds

Identification and Formation of Characteristic Volatile Compounds from Cooked Shrimp... 

Various kinds of heterocycles and two unsaturated methylketones were identified as characteristic components in the volatiles from cooked small shrimps. Without exception, they were all thermally generated compounds. Some volatile components from cooked small shrimps were in common with those of other animal protein foodstuffs like meat however, various types of compounds found in another foodstuffs were composed of the volatiles from specific shrimp species. Both the precursors and the formation pathways for the typical aroma compounds have already been elucidated, even though it is difficult to explain the different constituents of the volatile components among shrimp species. In future, it will be necessary to investigate the key factors which define the possible pathway to form characteristic volatiles in each foodstuff. 

Lobster and shrimp dine on carotenoid-containing plankton, and the compounds become concentrated in their shells. Here the carotenoids are bound up with protein molecules, and the carotenoid-protein complex has a dark green color. When the protein is heated, it is denatured. In other words, it breaks down and disassociates from the reddish pigment, astaxanthin, which then becomes visible. To a smaller extent this is also evident in cooked carrots, which become more orange than they were before. This was another experiment my daughter and I decided to try. We cooked up some fresh carrots to see if they would become more orange. They did, but the effect was not as pronounced as it was with the shrimp, because carrots have little protein. 

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