Are starch-thickened mixtures gels?

Good question, reader Nils, the answer to that is yes, though it’s a different sort of gelling process relative to a protein gel. In a protein gel the molecules that make up the network are bonded to each other chemically. The individual molecules bond end-to-end and side-to-side with one another inside a watery medium. The result is restricted flow and thickening. Starch gelling is a bit different. As starch molecules separate from the flour granules from which they came they get tangled up with each other. That tangle also restricts the flow of the water molecules around them and creates thickening. The key difference is that the starch molecules aren’t bonded to one another, or if they are only very weakly, and will wash away if the heating process goes on too long. In that case the flour granules in the mixture dissolve completely and the whole network collapses. Great question!

2 thoughts on “Are starch-thickened mixtures gels?”

  1. This is off the wall but it’s something I have thought about. I made the “family meal” one day by simmering last nights chicken and some veggies then turning it into a stew by adding a large amount of leftover mashed potatoes. It made a nice stew but I was left wondering if the thickening was because of the starch from the potatoes, just their bulk of (what I assume) some combination of the two. Do you think you have a clue?

    P.S. Not only did it work but the texture was silky & everyone said I should do it again.

    1. Hey Frankly!

      Potato starch makes a gel just like a grain starch does. The mashing probably created enough small particles of starch that they dispersed in the broth and…ta da!

      Nice idea…I may try that myself!


      – Joe

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