We have a hard problem with CTab procedure in plants. We usually extract DNA from Oaks, Pines, Platanus spp., and Oregano (Polyominthia spp.) and like 1-2 months ago the final product its a "milky solution" when its freezed at -20ºC. The problem doesn't stop here, because when we charge the "milky" samples to an agarose gel 1% it doesn't run, and of course doesn't work at all. We use this protocol for like 7 or 8 years ( Doyle & Doyle protocol), so we already had good results with all type of plants we usually use, and right now is not working.
So, we made new CTab buffer and changed all the reagents and we still have the same issue.
I added an image of few samples we had, they are freezed and when you unfreeze them, they are transparent.