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Why does boiling water always seem to release and become the colors of whatever vegetables I am boiling?

For example, beet root and red cabbage both vividly color hot water.

I'd assume it's something to do with collisions with water particles breaking down cell walls and releasing anthocyanin, but how would this work on a cellular level? I.e., how does boiling water succeed in breaking through (correct assumption?) cell walls?

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    $\begingroup$ Cell walls are permeable to small molecules. $\endgroup$
    – WYSIWYG
    Oct 17, 2016 at 18:34
  • $\begingroup$ I'd like to add that it depens on the solvebt too. anthocyanins are water soluble and hence beetroot gives the purple color when boiled in water. Similarly, boiling a carrot in water wont gove orange. Boiling a carrot in oil would. Carotenes are fat soluble. $\endgroup$
    – Polisetty
    Oct 17, 2016 at 22:13
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    $\begingroup$ take a look at this answer: chemistry.stackexchange.com/questions/61138/… your question is exactly the same $\endgroup$
    – KingBoomie
    Oct 18, 2016 at 14:44
  • $\begingroup$ @RickBeeloo Really? I don't believe you $\endgroup$
    – minseong
    Oct 18, 2016 at 19:14
  • $\begingroup$ You posted it yourself @theonlygusti $\endgroup$
    – KingBoomie
    Oct 18, 2016 at 20:19

1 Answer 1

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Why boiling water releases dyes from vegetables:

  • In general, one would need a solvent to extract compounds from the vegetables. Water is a solvent for the coloured pigments. In air or oil, the same pigments are less or even not at all soluble.
  • Hot water can damage cells. Proteins, which give structure to cells and membranes, denature at hot temperatures. Cell walls, by the way, are much more robust than membranes.
  • But even in cold water, some pigments can pass through membranes or membrane channels by diffusion. This will only take more time.

There are possibly other factors that are more case (vegetable) specific.

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  • $\begingroup$ Would the cell walls break down in boiling water? I.e., which of your listed factors contributes most significantly towards the final dye extraction? $\endgroup$
    – minseong
    Oct 17, 2016 at 19:57
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    $\begingroup$ Not the cell wall (fibrous structure), but cell membranes (oil bi-layer). With boiling water I assume it to be the most significant factor. $\endgroup$
    – setempler
    Oct 19, 2016 at 7:19

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