I have been learning about the practice of pre-gelatinization (scalding) of rye in the preparation of high-percentage rye breads.  One thing confuses me, however, with regards to the intended effect this has on the final dough. As I understand it, pre-gelatinization is a process typically used to make starches, in a given grain, MORE accessible to amylase (for example in brewing) In a wheat flour & water mixture the amylase starts to denature at temperatures above about 150Fl. In brewing (where diastatic malt is ADDED) careful control of this temperature during the mash can determine the ratio of alpha to beta amylase and thus fermentable vs. unfermentable sugars (for brewer's yeast). 

However in the case of rye, I understand that rye amylase is more heat-stable. I would think gelatinization is precisely the OPPOSITE of what one should be striving for  since the integrity of the pentosans in the rye is the major factor in preserving structure and preventing gumminess. Making them MORE vulnerable to amylase, earlier on in the 'production' process should surely be avoided? While the acidity of the rye sour should control the effects of amylase somewhat, one is still left with the question as to why scalding is done at all? A sweeter end result perhaps? 

All of which leads me to think that scalding the rye, in order to be effective, must be carried out at a fairly high temperature in order to denature the rye amylase...but what temperature might that be?  What proportion of the total rye flour (say in a 100% rye bread) should/could be scalded? Are there additional benefits from scalding rye that I am missing here?

If anyone has knowledge in this area, I'd be most appreciative of your input.

Thanks

FP