Vinegar mixed in pretzel dough?
I've been scouring the internet and books trying to find, what I'd call "trade secrets" of pretzel making. The basic properties of the pretzel taste is about contrast in pH. Which, is why a strong alkalie solution is used to dip the pretzels, imparting its wonderful flavor on the crust, so it will act in contrast with an acidic crumb taste.
I came across a recipe which used vinegar mixed in with the dough. I don't really understand why they'd use vinegar, except to act in contrast to the flavor of the crust. I got to thinking, if this was a similar flavor to what's expected when making sourdough soft pretzels. It imparts a certain tang to the crumb. Does this make sense to anyone? Do you think there will be adverse effects from using vinegar? What does it do to the gluten structure? What kind of reactions does it have with other ingredients- yeast, sourdough, fats, sweetners, salt, milk, etc.?
The recipe is as follows:
Flour 8 lb.- 128 oz. - 100%
Water 4 lb.- 64 oz.- 50%
Yeast 4 0z.- 3.1%
Salt 3 oz.- 2.3%
Sugar 3 oz.- 2.3%
Shortnening 2 oz.- 1.6%
Vinegar 0.5 oz.- .4%
Powdered milk 0.5 oz.- .4%
I also don't know when they'd introduce vinegar to the mix, considering this is a recipe I found while searching patents. This is the link to the patent, if curious. http://www.google.com/patents/US3876815?printsec=abstract&dq=3876815&ei=a_RlUamXL-nM2gXRsYHADQ#v=onepage&q=3876815&f=false 
I plan on giving this a try with or without advice, but I figured it's smarter to seek knowledge first. I don't know when I plan on making pretzels next, considering I'm in the middle of heavily researching a new recipe, but sooner or later I will post my results and conclusions. Maybe for national pretzel day, which is April 26th, if anyone was curious.
Thanks in advance for any information.