We like tomato sauce, but one must be careful with what to put into the dishwasher, to not have plastic bowls, storage boxes or other things dyed red…Why is tomato sauce this potent in coloring plastic. It’s like it’s in the fabric of the plastic itself after it comes out of the dishwasher…why not the same effect with strawberries or raspberries? And is there a way to prevent this?
Edit: Wow, this got some momentum…I see a lot of people like tomato sauces. Thanks for the awards as well!
In: Chemistry
As other folks have already mentioned, the pigments are different. In fact, there are three types of red pigment you’ll commonly see in plant foods: anthocyanins (most common), carotenoids (tomatoes, peppers, turmeric), and betalains (mostly in beets).
If you cook a dish with red cabbage, say, you will see the color stays in the water based part of the food, and avoids any oil drops you see. Also, the color will shift to bluish (even greenish!) unless you add a lot of acid, which will shift it back to red. Both of these behaviours are characteristic of anthocyanins, though the color range depends on which variation you have.
If, on the other hand, you have a tomato sauce, then the oil droplets will turn red or orange, because the underlying pigment is more waxy/oily. Similarly, some plastics (especially polyethylene and polypropylene) are basically solid waxes/oils, so the pigment happily dissolves in them. Many carotenoids will shift between pale, yellow, and red depending on conditions but blue shades not so much.
Finally, beets! The red stuff in beets is different yet again. It also has a strong preference for water, so won’t stain plastic. They don’t color shift as dramatically as anthocyanins. Also your body doesn’t metabolize them as aggressively, so they turn your pee and poop red if you eat a lot. Betalains are only common in one order of plants, I think. So beets/poke/amaranth and maybe cactus.
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