Gluten gone bad
I have a gluten question:
What could have possibly happened to the gluten structure during the first rise of my bread today?
This was a cinnamon/raisin bread which I've done many, many times with dry commercial yeast (recipe from RL Beranbaum's "The Bread Bible"), but this time, tried with a starter. My first attempt at this was more successful, but something strange happened today.
After the first rise, I noticed on the (one and only) stretch and fold that the consistency was a bit off, the stretchy, elasticity of the dough was not the same. Subsequently after an hour in the fridge (recipe calls for this prior to shaping), it seemed there was very little gluten support, as the dough just seemed to have no elasticity and easily broke apart when stretching and shaping. Something happened, and I'm not sure what??
I've done a lot of reading so far on this site. Possible culprits that I can come up with are perhaps, some lactobacilli species in my starter that may have enzyme activity against the gluten, or perhaps the dry milk powder (use Bob's Red Mill) having the same enzyme activity? The initial mix seemed adequate. I don't think I overmixed.
Temp of first rise was mid 70's, this took about 7 hours (consistent with my first successful attempt at this recipe).
Any ideas would be greatly appreciated.
(I'm allowing it to rise as much as possible, and I'll bake it anyways, but the surface of the proofing loaf is split in several locations, and I doubt it has the ability to rise much more)