A non-disclosure agreement (NDA), also known as a confidentiality agreement (CA), confidential disclosure agreement (CDA), proprietary information agreement (PIA), or secrecy agreement, is a legal contract between at least two parties that outlines confidential material, knowledge, or information that the parties wish to share with one another for certain purposes, but wish to restrict access to or by third parties. It's a contract through which the parties agree not to disclose information covered by the agreement. An NDA creates a confidential relationship between the parties to protect any type of confidential and proprietary information or trade secrets. As such, an NDA protects nonpublic business information.
Reference: Non-disclosure agreement
This means that you can't use any of the material you have produced even if you remove company information on the material. So this is out of the question. But, you can change the material in such a way that it cannot be recognized as the original - or you can make new ones, which is even better.
The point in putting things into the portfolio is to show your knowledge and skills in this particular area. Not to show everything that you have done. Select the two best wireframes, the two best prototypes, the two best personas, the two best use cases and let it all be a nice thing to experience for the reader of the portfolio.
If you can add all things from the same project you gain by showing the actual process and progress of the project until the finished product. If that product is a web site - it is hopefully public, and you can show the end result based on your teamwork!
But the portfolios job is only to get you to the interview, passing everybody else, not coming to the interview. For that interview you need to be prepared, and know what to say on each project. What you contibuted to, how you made the product more useful and joyful for user and how that increased sales|visits|convertion rates. Think these things through as well - and I'm sure you will get yourself the job you want.