Re: Why doesn't tomato sauce come off plastic cookware?

The red color that sticks to the plastic cookware is called lycopene. It is the chemical that gives tomatoes their rich red color. The compound itself is a monstrous hydrocarbon with zillions of double bonds (if you want to look it up, it is (gamma, gamma)-carotene, aka lycopene, Merck Index 11th ed. entry 5492).

As for why it sticks to the cookware, I do not know of any studies that have been done, nor have I found any references. It is possible (and this is purely an educated guess) that, at high temperatures, this highly- unsaturated molecule may actually react with the plastic, perhaps by copolymerization with residual double bonds therein. It is also possible that, as it is a hydrocarbon, it simply possesses a high binding affinity with the hydrocarbon polymer that makes up most plastic cookware.

In either case, a good soaking with bleach will destroy the lycopene, and leave your cookware looking and smelling like new. Alternatively, you can make your tomato sauce entirely out of yellow tomatoes. This has a tendency to turn the stomachs of Italian purists, so be forewarned.