Earlier in this thread, at Reply 9 at http://www.pizzamaking.com/forum/index.php/topic,6758.msg58413.html#msg58413,
in response to a post by marc (widespreadpizza), there was a discussion of a supposed "mysterious ingredient" use in the Papa John's dough. Off and on, including recently at the thread at http://www.pizzamaking.com/forum/index.php/topic,13725.msg137596.html#msg137596,
there have been other attempts to resolve the mystery. As I noted earlier today at Reply 11 in that thread, I believe I have solved the mystery.
Solving the mystery was actually quite simple. I just called Papa John's, at the telephone number (1-888-404-7537) that I have used before to speak to someone at PJs about their products. I ended up being connected to Diane Helms. I had spoken to her before and assumed that she was just a customer service rep but one with a good working knowledge of the ingredients that go into their products and the related nutrition information. As it turns out, she is the PJ manager of domestic R&D. I even later found a photo of her at http://www.dnj.com/article/B2/20110507/BUSINESS/305080035/Papa-John-s-gains-heat-up-pizza-race.
(Note: See EDIT below for a working link of a photo of Ms. Helms).
I asked Diane about the reference by John Schnatter (the founder and CEO of PJs) in the PJ Facebook video at http://www.newlocaltv.com/media-center.html?videoid=76
to a particular kind of seed used to make the PJ flour. As previously noted, the reference is at about 3:15 in the video. I asked Diane what John Schnatter was saying about that seed. She said it is the Platte River seed. She went on to explain that that seed was developed specifically for PJs in order to achieve a particular flavor in the finished crust, a point she emphasized a few times during our conversation. The flour itself is a proprietary flour that is milled specifically for PJs, and whichever miller does the milling for PJs is not permitted to sell the flour to anyone else. It is exclusive to PJs. Diane believes that the name Platte River was given to the flour by people who were involved in coming up with the particular seed used to make the flour. It is not something that someone can go and ask for and expect to end up with the PJ flour. For what it is worth, a quick Google search shows that there is apparently a Platte River in Nebraska. Nebraska happens to be one of the growing areas for hard red spring wheat.
I also asked Diane about the protein content of the PJ flour. I specifically mentioned that at one time PJs promoted their flour as being a "high-gluten" flour. She said that that was still true. When I said that to me "high gluten" meant around 14% protein, she said "Well, it isn't quite that high". As I have mentioned before, I have suspected that PJ's flour was in the 13.0-14% range. I think that that may also be true of many of the large pizza chains. For one thing, it tends to lend itself better to a delivery type pizza than a pure high-gluten flour that can lead to an overly chewy and leathery crust when it cools down during delivery.
EDIT (8/10/12): For a replacement link showing a photo of Ms. Helms, see http://www.comparechains.com/team/.
EDIT 2 (10/25/13): Replaced the Facebook video link with another video link
EDIT 3 (6/8/14): For additional commentary on the Schnatter video, see http://louisville.eater.com/archives/2013/08/19/papa-john-revealed-some-of-his-pizza-ingredients-in-2010.php