When searching through OST/PST files the email address is included if it's there. Here's an example of an email extracted with FileLocator Pro (email addresses altered):
From: John Brown <firstname.lastname@example.org>
To: Sarah Smith <email@example.com>
Received by: firstname.lastname@example.org
Sent: 31/12/2012 15:34:56
Subject: RE: Your recent proposal
Thanks for the email. etc.
As you can see if there is both a Display Name and Email the email is displayed in angled brackets.
If you're experiencing something different could you please add a screenshot to your question?